xref: /freebsd/contrib/bmake/bmake.cat1 (revision 0b46a53a2f50b5ab0f4598104119a049b9c42cc9)
1BMAKE(1)                FreeBSD General Commands Manual               BMAKE(1)
2
3NNAAMMEE
4     bbmmaakkee - maintain program dependencies
5
6SSYYNNOOPPSSIISS
7     bbmmaakkee [--BBeeiikkNNnnqqrrSSssttWWwwXX] [--CC _d_i_r_e_c_t_o_r_y] [--DD _v_a_r_i_a_b_l_e] [--dd _f_l_a_g_s]
8           [--ff _m_a_k_e_f_i_l_e] [--II _d_i_r_e_c_t_o_r_y] [--JJ _p_r_i_v_a_t_e] [--jj _m_a_x___j_o_b_s]
9           [--mm _d_i_r_e_c_t_o_r_y] [--TT _f_i_l_e] [--VV _v_a_r_i_a_b_l_e] [--vv _v_a_r_i_a_b_l_e]
10           [_v_a_r_i_a_b_l_e==_v_a_l_u_e] [_t_a_r_g_e_t ...]
11
12DDEESSCCRRIIPPTTIIOONN
13     bbmmaakkee is a program designed to simplify the maintenance of other
14     programs.  Its input is a list of specifications as to the files upon
15     which programs and other files depend.  If no --ff _m_a_k_e_f_i_l_e option is
16     given, bbmmaakkee looks for the makefiles listed in _._M_A_K_E_._M_A_K_E_F_I_L_E___P_R_E_F_E_R_E_N_C_E
17     (default `_m_a_k_e_f_i_l_e', `_M_a_k_e_f_i_l_e') in order to find the specifications.  If
18     the file `_._d_e_p_e_n_d' exists, it is read, see mkdep(1).
19
20     This manual page is intended as a reference document only.  For a more
21     thorough description of bbmmaakkee and makefiles, please refer to _P_M_a_k_e _- _A
22     _T_u_t_o_r_i_a_l (from 1993).
23
24     bbmmaakkee prepends the contents of the MAKEFLAGS environment variable to the
25     command line arguments before parsing them.
26
27     The options are as follows:
28
29     --BB      Try to be backwards compatible by executing a single shell per
30             command and by making the sources of a dependency line in
31             sequence.
32
33     --CC _d_i_r_e_c_t_o_r_y
34             Change to _d_i_r_e_c_t_o_r_y before reading the makefiles or doing
35             anything else.  If multiple --CC options are specified, each is
36             interpreted relative to the previous one: --CC _/ --CC _e_t_c is
37             equivalent to --CC _/_e_t_c.
38
39     --DD _v_a_r_i_a_b_l_e
40             Define _v_a_r_i_a_b_l_e to be 1, in the global scope.
41
42     --dd [--]_f_l_a_g_s
43             Turn on debugging, and specify which portions of bbmmaakkee are to
44             print debugging information.  Unless the flags are preceded by
45             `-', they are added to the MAKEFLAGS environment variable and are
46             passed on to any child make processes.  By default, debugging
47             information is printed to standard error, but this can be changed
48             using the FF debugging flag.  The debugging output is always
49             unbuffered; in addition, if debugging is enabled but debugging
50             output is not directed to standard output, the standard output is
51             line buffered.  The available _f_l_a_g_s are:
52
53             AA       Print all possible debugging information; equivalent to
54                     specifying all of the debugging flags.
55
56             aa       Print debugging information about archive searching and
57                     caching.
58
59             CC       Print debugging information about the current working
60                     directory.
61
62             cc       Print debugging information about conditional evaluation.
63
64             dd       Print debugging information about directory searching and
65                     caching.
66
67             ee       Print debugging information about failed commands and
68                     targets.
69
70             FF[++]_f_i_l_e_n_a_m_e
71                     Specify where debugging output is written.  This must be
72                     the last flag, because it consumes the remainder of the
73                     argument.  If the character immediately after the FF flag
74                     is `+', the file is opened in append mode; otherwise the
75                     file is overwritten.  If the file name is `stdout' or
76                     `stderr', debugging output is written to the standard
77                     output or standard error output respectively (and the `+'
78                     option has no effect).  Otherwise, the output is written
79                     to the named file.  If the file name ends with `.%d', the
80                     `%d' is replaced by the pid.
81
82             ff       Print debugging information about loop evaluation.
83
84             gg11      Print the input graph before making anything.
85
86             gg22      Print the input graph after making everything, or before
87                     exiting on error.
88
89             gg33      Print the input graph before exiting on error.
90
91             hh       Print debugging information about hash table operations.
92
93             jj       Print debugging information about running multiple
94                     shells.
95
96             LL       Turn on lint checks.  This throws errors for variable
97                     assignments that do not parse correctly, at the time of
98                     assignment, so the file and line number are available.
99
100             ll       Print commands in Makefiles regardless of whether or not
101                     they are prefixed by `@' or other "quiet" flags.  Also
102                     known as "loud" behavior.
103
104             MM       Print debugging information about "meta" mode decisions
105                     about targets.
106
107             mm       Print debugging information about making targets,
108                     including modification dates.
109
110             nn       Don't delete the temporary command scripts created when
111                     running commands.  These temporary scripts are created in
112                     the directory referred to by the TMPDIR environment
113                     variable, or in _/_t_m_p if TMPDIR is unset or set to the
114                     empty string.  The temporary scripts are created by
115                     mkstemp(3), and have names of the form _m_a_k_e_X_X_X_X_X_X.  _N_O_T_E:
116                     This can create many files in TMPDIR or _/_t_m_p, so use with
117                     care.
118
119             pp       Print debugging information about makefile parsing.
120
121             ss       Print debugging information about suffix-transformation
122                     rules.
123
124             tt       Print debugging information about target list
125                     maintenance.
126
127             VV       Force the --VV option to print raw values of variables,
128                     overriding the default behavior set via
129                     _._M_A_K_E_._E_X_P_A_N_D___V_A_R_I_A_B_L_E_S.
130
131             vv       Print debugging information about variable assignment and
132                     expansion.
133
134             xx       Run shell commands with --xx so the actual commands are
135                     printed as they are executed.
136
137     --ee      Let environment variables override global variables within
138             makefiles.
139
140     --ff _m_a_k_e_f_i_l_e
141             Specify a makefile to read instead of one of the defaults listed
142             in _._M_A_K_E_._M_A_K_E_F_I_L_E___P_R_E_F_E_R_E_N_C_E.  If _m_a_k_e_f_i_l_e is `-', standard input
143             is read.  If _m_a_k_e_f_i_l_e starts with the string `.../', bbmmaakkee
144             searches for the specified path in the rest of the argument in
145             the current directory and its parents.  Multiple makefiles may be
146             specified, and are read in the order specified.
147
148     --II _d_i_r_e_c_t_o_r_y
149             Specify a directory in which to search for makefiles and included
150             makefiles.  The system makefile directory (or directories, see
151             the --mm option) is automatically included as part of this list.
152
153     --ii      Ignore non-zero exit of shell commands in the makefile.
154             Equivalent to specifying `-' before each command line in the
155             makefile.
156
157     --JJ _p_r_i_v_a_t_e
158             This option should _n_o_t be specified by the user.
159
160             When the --jj option is in use in a recursive build, this option is
161             passed by a make to child makes to allow all the make processes
162             in the build to cooperate to avoid overloading the system.
163
164     --jj _m_a_x___j_o_b_s
165             Specify the maximum number of jobs that bbmmaakkee may have running at
166             any one time.  If _m_a_x___j_o_b_s is a floating point number, or ends
167             with `C', then the value is multiplied by the number of CPUs
168             reported online by sysconf(3).  The value of _m_a_x___j_o_b_s is saved in
169             _._M_A_K_E_._J_O_B_S.  Turns compatibility mode off, unless the --BB option
170             is also specified.  When compatibility mode is off, all commands
171             associated with a target are executed in a single shell
172             invocation as opposed to the traditional one shell invocation per
173             line.  This can break traditional scripts which change
174             directories on each command invocation and then expect to start
175             with a fresh environment on the next line.  It is more efficient
176             to correct the scripts rather than turn backwards compatibility
177             on.
178
179             A job token pool with _m_a_x___j_o_b_s tokens is used to control the
180             total number of jobs running.  Each instance of bbmmaakkee will wait
181             for a token from the pool before running a new job.
182
183     --kk      Continue processing after errors are encountered, but only on
184             those targets that do not depend on the target whose creation
185             caused the error.
186
187     --mm _d_i_r_e_c_t_o_r_y
188             Specify a directory in which to search for _s_y_s_._m_k and makefiles
189             included via the <_f_i_l_e>-style include statement.  The --mm option
190             can be used multiple times to form a search path.  This path
191             overrides the default system include path _/_u_s_r_/_s_h_a_r_e_/_m_k.
192             Furthermore, the system include path is appended to the search
193             path used for "_f_i_l_e"-style include statements (see the --II
194             option).  The system include path can be referenced via the read-
195             only variable _._S_Y_S_P_A_T_H.
196
197             If a directory name in the --mm argument (or the MAKESYSPATH
198             environment variable) starts with the string `.../', bbmmaakkee
199             searches for the specified file or directory named in the
200             remaining part of the argument string.  The search starts with
201             the current directory and then works upward towards the root of
202             the file system.  If the search is successful, the resulting
203             directory replaces the `.../' specification in the --mm argument.
204             This feature allows bbmmaakkee to easily search in the current source
205             tree for customized _s_y_s_._m_k files (e.g., by using `.../mk/sys.mk'
206             as an argument).
207
208     --nn      Display the commands that would have been executed, but do not
209             actually execute them unless the target depends on the _._M_A_K_E
210             special source (see below) or the command is prefixed with `++'.
211
212     --NN      Display the commands that would have been executed, but do not
213             actually execute any of them; useful for debugging top-level
214             makefiles without descending into subdirectories.
215
216     --qq      Do not execute any commands, instead exit 0 if the specified
217             targets are up to date, and 1 otherwise.
218
219     --rr      Do not use the built-in rules specified in the system makefile.
220
221     --SS      Stop processing if an error is encountered.  This is the default
222             behavior and the opposite of --kk.
223
224     --ss      Do not echo any commands as they are executed.  Equivalent to
225             specifying `@@' before each command line in the makefile.
226
227     --TT _t_r_a_c_e_f_i_l_e
228             When used with the --jj flag, append a trace record to _t_r_a_c_e_f_i_l_e
229             for each job started and completed.
230
231     --tt      Rather than re-building a target as specified in the makefile,
232             create it or update its modification time to make it appear up-
233             to-date.
234
235     --VV _v_a_r_i_a_b_l_e
236             Print the value of _v_a_r_i_a_b_l_e.  Do not build any targets.  Multiple
237             instances of this option may be specified; the variables are
238             printed one per line, with a blank line for each null or
239             undefined variable.  The value printed is extracted from the
240             global scope after all makefiles have been read.
241
242             By default, the raw variable contents (which may include
243             additional unexpanded variable references) are shown.  If
244             _v_a_r_i_a_b_l_e contains a `$', it is not interpreted as a variable name
245             but rather as an expression.  Its value is expanded before
246             printing.  The value is also expanded before printing if
247             _._M_A_K_E_._E_X_P_A_N_D___V_A_R_I_A_B_L_E_S is set to true and the --ddVV option has not
248             been used to override it.
249
250             Note that loop-local and target-local variables, as well as
251             values taken temporarily by global variables during makefile
252             processing, are not accessible via this option.  The --ddvv debug
253             mode can be used to see these at the cost of generating
254             substantial extraneous output.
255
256     --vv _v_a_r_i_a_b_l_e
257             Like --VV, but all printed variables are always expanded to their
258             complete value.  The last occurrence of --VV or --vv decides whether
259             all variables are expanded or not.
260
261     --WW      Treat any warnings during makefile parsing as errors.
262
263     --ww      Print entering and leaving directory messages, pre and post
264             processing.
265
266     --XX      Don't export variables passed on the command line to the
267             environment individually.  Variables passed on the command line
268             are still exported via the MAKEFLAGS environment variable.  This
269             option may be useful on systems which have a small limit on the
270             size of command arguments.
271
272     _v_a_r_i_a_b_l_e==_v_a_l_u_e
273             Set the value of the variable _v_a_r_i_a_b_l_e to _v_a_l_u_e.  Normally, all
274             values passed on the command line are also exported to sub-makes
275             in the environment.  The --XX flag disables this behavior.
276             Variable assignments should follow options for POSIX
277             compatibility but no ordering is enforced.
278
279     There are several different types of lines in a makefile: dependency
280     specifications, shell commands, variable assignments, include statements,
281     conditional directives, for loops, other directives, and comments.
282
283     Lines may be continued from one line to the next by ending them with a
284     backslash (`\').  The trailing newline character and initial whitespace
285     on the following line are compressed into a single space.
286
287FFIILLEE DDEEPPEENNDDEENNCCYY SSPPEECCIIFFIICCAATTIIOONNSS
288     Dependency lines consist of one or more targets, an operator, and zero or
289     more sources.  This creates a relationship where the targets "depend" on
290     the sources and are customarily created from them.  A target is
291     considered out of date if it does not exist, or if its modification time
292     is less than that of any of its sources.  An out-of-date target is re-
293     created, but not until all sources have been examined and themselves re-
294     created as needed.  Three operators may be used:
295
296     ::     Many dependency lines may name this target but only one may have
297           attached shell commands.  All sources named in all dependency lines
298           are considered together, and if needed the attached shell commands
299           are run to create or re-create the target.  If bbmmaakkee is
300           interrupted, the target is removed.
301
302     !!     The same, but the target is always re-created whether or not it is
303           out of date.
304
305     ::::    Any dependency line may have attached shell commands, but each one
306           is handled independently: its sources are considered and the
307           attached shell commands are run if the target is out of date with
308           respect to (only) those sources.  Thus, different groups of the
309           attached shell commands may be run depending on the circumstances.
310           Furthermore, unlike ::, for dependency lines with no sources, the
311           attached shell commands are always run.  Also unlike ::, the target
312           is not removed if bbmmaakkee is interrupted.
313
314     All dependency lines mentioning a particular target must use the same
315     operator.
316
317     Targets and sources may contain the shell wildcard values `?', `*', `[]',
318     and `{}'.  The values `?', `*', and `[]' may only be used as part of the
319     final component of the target or source, and only match existing files.
320     The value `{}' need not necessarily be used to describe existing files.
321     Expansion is in directory order, not alphabetically as done in the shell.
322
323SSHHEELLLL CCOOMMMMAANNDDSS
324     Each target may have associated with it one or more lines of shell
325     commands, normally used to create the target.  Each of the lines in this
326     script _m_u_s_t be preceded by a tab.  (For historical reasons, spaces are
327     not accepted.)  While targets can occur in many dependency lines if
328     desired, by default only one of these rules may be followed by a creation
329     script.  If the `::::' operator is used, however, all rules may include
330     scripts, and the respective scripts are executed in the order found.
331
332     Each line is treated as a separate shell command, unless the end of line
333     is escaped with a backslash `\', in which case that line and the next are
334     combined.  If the first characters of the command are any combination of
335     `@@', `++', or `--', the command is treated specially.
336
337           @@       causes the command not to be echoed before it is executed.
338
339           ++       causes the command to be executed even when --nn is given.
340                   This is similar to the effect of the _._M_A_K_E special source,
341                   except that the effect can be limited to a single line of a
342                   script.
343
344           --       in compatibility mode causes any non-zero exit status of
345                   the command line to be ignored.
346
347     When bbmmaakkee is run in jobs mode with --jj _m_a_x___j_o_b_s, the entire script for
348     the target is fed to a single instance of the shell.  In compatibility
349     (non-jobs) mode, each command is run in a separate process.  If the
350     command contains any shell meta characters (`#=|^(){};&<>*?[]:$`\\n'), it
351     is passed to the shell; otherwise bbmmaakkee attempts direct execution.  If a
352     line starts with `--' and the shell has ErrCtl enabled, failure of the
353     command line is ignored as in compatibility mode.  Otherwise `--' affects
354     the entire job; the script stops at the first command line that fails,
355     but the target is not deemed to have failed.
356
357     Makefiles should be written so that the mode of bbmmaakkee operation does not
358     change their behavior.  For example, any command which uses "cd" or
359     "chdir" without the intention of changing the directory for subsequent
360     commands should be put in parentheses so it executes in a subshell.  To
361     force the use of a single shell, escape the line breaks so as to make the
362     whole script one command.  For example:
363
364           avoid-chdir-side-effects:
365                   @echo "Building $@ in $$(pwd)"
366                   @(cd ${.CURDIR} && ${MAKE} $@)
367                   @echo "Back in $$(pwd)"
368
369           ensure-one-shell-regardless-of-mode:
370                   @echo "Building $@ in $$(pwd)"; \
371                   (cd ${.CURDIR} && ${MAKE} $@); \
372                   echo "Back in $$(pwd)"
373
374     Since bbmmaakkee changes the current working directory to `_._O_B_J_D_I_R' before
375     executing any targets, each child process starts with that as its current
376     working directory.
377
378VVAARRIIAABBLLEE AASSSSIIGGNNMMEENNTTSS
379     Variables in make behave much like macros in the C preprocessor.
380
381     Variable assignments have the form `_N_A_M_E _o_p _v_a_l_u_e', where:
382
383           _N_A_M_E    is a single-word variable name, consisting, by tradition,
384                   of all upper-case letters,
385
386           _o_p      is one of the variable assignment operators described
387                   below, and
388
389           _v_a_l_u_e   is interpreted according to the variable assignment
390                   operator.
391
392     Whitespace around _N_A_M_E, _o_p and _v_a_l_u_e is discarded.
393
394   VVaarriiaabbllee aassssiiggnnmmeenntt ooppeerraattoorrss
395     The five operators that assign values to variables are:
396
397     ==       Assign the value to the variable.  Any previous value is
398             overwritten.
399
400     ++==      Append the value to the current value of the variable, separating
401             them by a single space.
402
403     ??==      Assign the value to the variable if it is not already defined.
404
405     ::==      Expand the value, then assign it to the variable.
406
407             _N_O_T_E: References to undefined variables are _n_o_t expanded.  This
408             can cause problems when variable modifiers are used.
409
410     !!==      Expand the value and pass it to the shell for execution, then
411             assign the output from the child's standard output to the
412             variable.  Any newlines in the result are replaced with spaces.
413
414   EExxppaannssiioonn ooff vvaarriiaabblleess
415     In most contexts where variables are expanded, `$$' expands to a single
416     dollar sign.  In other contexts (most variable modifiers, string literals
417     in conditions), `\$' expands to a single dollar sign.
418
419     References to variables have the form $${{_n_a_m_e[::_m_o_d_i_f_i_e_r_s]}} or
420     $$((_n_a_m_e[::_m_o_d_i_f_i_e_r_s])).  If the variable name consists of only a single
421     character and the expression contains no modifiers, the surrounding curly
422     braces or parentheses are not required.  This shorter form is not
423     recommended.
424
425     If the variable name contains a dollar, the name itself is expanded
426     first.  This allows almost arbitrary variable names, however names
427     containing dollar, braces, parentheses or whitespace are really best
428     avoided.
429
430     If the result of expanding a nested variable expression contains a dollar
431     sign (`$'), the result is subject to further expansion.
432
433     Variable substitution occurs at four distinct times, depending on where
434     the variable is being used.
435
436     1.   Variables in dependency lines are expanded as the line is read.
437
438     2.   Variables in conditionals are expanded individually, but only as far
439          as necessary to determine the result of the conditional.
440
441     3.   Variables in shell commands are expanded when the shell command is
442          executed.
443
444     4.   ..ffoorr loop index variables are expanded on each loop iteration.  Note
445          that other variables are not expanded when composing the body of a
446          loop, so the following example code:
447
448                .for i in 1 2 3
449                a+=     ${i}
450                j=      ${i}
451                b+=     ${j}
452                .endfor
453
454                all:
455                        @echo ${a}
456                        @echo ${b}
457
458          prints:
459
460                1 2 3
461                3 3 3
462
463          After the loop is executed:
464
465                _a       contains `${:U1} ${:U2} ${:U3}', which expands to `1 2
466                        3'.
467
468                _j       contains `${:U3}', which expands to `3'.
469
470                _b       contains `${j} ${j} ${j}', which expands to `${:U3}
471                        ${:U3} ${:U3}' and further to `3 3 3'.
472
473   VVaarriiaabbllee ccllaasssseess
474     The four different classes of variables (in order of increasing
475     precedence) are:
476
477     Environment variables
478             Variables defined as part of bbmmaakkee's environment.
479
480     Global variables
481             Variables defined in the makefile or in included makefiles.
482
483     Command line variables
484             Variables defined as part of the command line.
485
486     Local variables
487             Variables that are defined specific to a certain target.
488
489     Local variables can be set on a dependency line, unless
490     _._M_A_K_E_._T_A_R_G_E_T___L_O_C_A_L___V_A_R_I_A_B_L_E_S is set to `false'.  The rest of the line
491     (which already has had global variables expanded) is the variable value.
492     For example:
493
494           COMPILER_WRAPPERS= ccache distcc icecc
495
496           ${OBJS}: .MAKE.META.CMP_FILTER=${COMPILER_WRAPPERS:S,^,N,}
497
498     Only the targets `${OBJS}' are impacted by that filter (in "meta" mode)
499     and simply enabling/disabling any of the compiler wrappers does not
500     render all of those targets out-of-date.
501
502     _N_O_T_E: target-local variable assignments behave differently in that;
503
504           ++==      Only appends to a previous local assignment for the same
505                   target and variable.
506
507           ::==      Is redundant with respect to global variables, which have
508                   already been expanded.
509
510     The seven built-in local variables are:
511
512           _._A_L_L_S_R_C   The list of all sources for this target; also known as
513                     `_>'.
514
515           _._A_R_C_H_I_V_E  The name of the archive file; also known as `_!'.
516
517           _._I_M_P_S_R_C   In suffix-transformation rules, the name/path of the
518                     source from which the target is to be transformed (the
519                     "implied" source); also known as `_<'.  It is not defined
520                     in explicit rules.
521
522           _._M_E_M_B_E_R   The name of the archive member; also known as `_%'.
523
524           _._O_O_D_A_T_E   The list of sources for this target that were deemed out-
525                     of-date; also known as `_?'.
526
527           _._P_R_E_F_I_X   The name of the target with suffix (if declared in
528                     ..SSUUFFFFIIXXEESS) removed; also known as `_*'.
529
530           _._T_A_R_G_E_T   The name of the target; also known as `_@'.  For
531                     compatibility with other makes this is an alias for
532                     _._A_R_C_H_I_V_E in archive member rules.
533
534     The shorter forms (`_>', `_!', `_<', `_%', `_?', `_*', and `_@') are permitted
535     for backward compatibility with historical makefiles and legacy POSIX
536     make and are not recommended.
537
538     Variants of these variables with the punctuation followed immediately by
539     `D' or `F', e.g. `$(@D)', are legacy forms equivalent to using the `:H'
540     and `:T' modifiers.  These forms are accepted for compatibility with AT&T
541     System V UNIX makefiles and POSIX but are not recommended.
542
543     Four of the local variables may be used in sources on dependency lines
544     because they expand to the proper value for each target on the line.
545     These variables are `_._T_A_R_G_E_T', `_._P_R_E_F_I_X', `_._A_R_C_H_I_V_E', and `_._M_E_M_B_E_R'.
546
547   AAddddiittiioonnaall bbuuiilltt--iinn vvaarriiaabblleess
548     In addition, bbmmaakkee sets or knows about the following variables:
549
550     _._A_L_L_T_A_R_G_E_T_S
551             The list of all targets encountered in the makefiles.  If
552             evaluated during makefile parsing, lists only those targets
553             encountered thus far.
554
555     _._C_U_R_D_I_R
556             A path to the directory where bbmmaakkee was executed.  Refer to the
557             description of `_P_W_D' for more details.
558
559     _._E_R_R_O_R___C_M_D
560             Is used in error handling, see _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.
561
562     _._E_R_R_O_R___C_W_D
563             Is used in error handling, see _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.
564
565     _._E_R_R_O_R___E_X_I_T
566             Is used in error handling, see _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.
567
568     _._E_R_R_O_R___M_E_T_A___F_I_L_E
569             Is used in error handling in "meta" mode, see
570             _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.
571
572     _._E_R_R_O_R___T_A_R_G_E_T
573             Is used in error handling, see _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.
574
575     _._I_N_C_L_U_D_E_D_F_R_O_M_D_I_R
576             The directory of the file this makefile was included from.
577
578     _._I_N_C_L_U_D_E_D_F_R_O_M_F_I_L_E
579             The filename of the file this makefile was included from.
580
581     _M_A_C_H_I_N_E
582             The machine hardware name, see uname(1).
583
584     _M_A_C_H_I_N_E___A_R_C_H
585             The machine processor architecture name, see uname(1).
586
587     _M_A_K_E    The name that bbmmaakkee was executed with (_a_r_g_v_[_0_]).
588
589     _._M_A_K_E   The same as _M_A_K_E, for compatibility.  The preferred variable to
590             use is the environment variable MAKE because it is more
591             compatible with other make variants and cannot be confused with
592             the special target with the same name.
593
594     _._M_A_K_E_._D_E_P_E_N_D_F_I_L_E
595             Names the makefile (default `_._d_e_p_e_n_d') from which generated
596             dependencies are read.
597
598     _._M_A_K_E_._D_I_E___Q_U_I_E_T_L_Y
599             If set to `true', do not print error information at the end.
600
601     _._M_A_K_E_._E_X_P_A_N_D___V_A_R_I_A_B_L_E_S
602             A boolean that controls the default behavior of the --VV option.
603             If true, variable values printed with --VV are fully expanded; if
604             false, the raw variable contents (which may include additional
605             unexpanded variable references) are shown.
606
607     _._M_A_K_E_._E_X_P_O_R_T_E_D
608             The list of variables exported by bbmmaakkee.
609
610     _M_A_K_E_F_I_L_E
611             The top-level makefile that is currently read, as given in the
612             command line.
613
614     _._M_A_K_E_F_L_A_G_S
615             The environment variable `MAKEFLAGS' may contain anything that
616             may be specified on bbmmaakkee's command line.  Anything specified on
617             bbmmaakkee's command line is appended to the _._M_A_K_E_F_L_A_G_S variable,
618             which is then added to the environment for all programs that
619             bbmmaakkee executes.
620
621     _._M_A_K_E_._G_I_D
622             The numeric group ID of the user running bbmmaakkee.  It is read-only.
623
624     _._M_A_K_E_._J_O_B_._P_R_E_F_I_X
625             If bbmmaakkee is run with --jj, the output for each target is prefixed
626             with a token
627                   --- _t_a_r_g_e_t ---
628             the first part of which can be controlled via _._M_A_K_E_._J_O_B_._P_R_E_F_I_X.
629             If _._M_A_K_E_._J_O_B_._P_R_E_F_I_X is empty, no token is printed.  For example,
630             setting _._M_A_K_E_._J_O_B_._P_R_E_F_I_X to
631             `${.newline}---${.MAKE:T}[${.MAKE.PID}]' would produce tokens
632             like
633                   ---make[1234] _t_a_r_g_e_t ---
634             making it easier to track the degree of parallelism being
635             achieved.
636
637     _._M_A_K_E_._J_O_B_S
638             The argument to the --jj option.
639
640     _._M_A_K_E_._J_O_B_S_._C
641             A read-only boolean that indicates whether the --jj option supports
642             use of `C'.
643
644     _._M_A_K_E_._L_E_V_E_L
645             The recursion depth of bbmmaakkee.  The top-level instance of bbmmaakkee
646             has level 0, and each child make has its parent level plus 1.
647             This allows tests like: .if ${.MAKE.LEVEL} == 0 to protect things
648             which should only be evaluated in the top-level instance of
649             bbmmaakkee.
650
651     _._M_A_K_E_._L_E_V_E_L_._E_N_V
652             The name of the environment variable that stores the level of
653             nested calls to bbmmaakkee.
654
655     _._M_A_K_E_._M_A_K_E_F_I_L_E___P_R_E_F_E_R_E_N_C_E
656             The ordered list of makefile names (default `_m_a_k_e_f_i_l_e',
657             `_M_a_k_e_f_i_l_e') that bbmmaakkee looks for.
658
659     _._M_A_K_E_._M_A_K_E_F_I_L_E_S
660             The list of makefiles read by bbmmaakkee, which is useful for tracking
661             dependencies.  Each makefile is recorded only once, regardless of
662             the number of times read.
663
664     _._M_A_K_E_._M_E_T_A_._B_A_I_L_I_W_I_C_K
665             In "meta" mode, provides a list of prefixes which match the
666             directories controlled by bbmmaakkee.  If a file that was generated
667             outside of _._O_B_J_D_I_R but within said bailiwick is missing, the
668             current target is considered out-of-date.
669
670     _._M_A_K_E_._M_E_T_A_._C_M_P___F_I_L_T_E_R
671             In "meta" mode, it can (very rarely!) be useful to filter command
672             lines before comparison.  This variable can be set to a set of
673             modifiers that are applied to each line of the old and new
674             command that differ, if the filtered commands still differ, the
675             target is considered out-of-date.
676
677     _._M_A_K_E_._M_E_T_A_._C_R_E_A_T_E_D
678             In "meta" mode, this variable contains a list of all the meta
679             files updated.  If not empty, it can be used to trigger
680             processing of _._M_A_K_E_._M_E_T_A_._F_I_L_E_S.
681
682     _._M_A_K_E_._M_E_T_A_._F_I_L_E_S
683             In "meta" mode, this variable contains a list of all the meta
684             files used (updated or not).  This list can be used to process
685             the meta files to extract dependency information.
686
687     _._M_A_K_E_._M_E_T_A_._I_G_N_O_R_E___F_I_L_T_E_R
688             Provides a list of variable modifiers to apply to each pathname.
689             Ignore if the expansion is an empty string.
690
691     _._M_A_K_E_._M_E_T_A_._I_G_N_O_R_E___P_A_T_H_S
692             Provides a list of path prefixes that should be ignored; because
693             the contents are expected to change over time.  The default list
694             includes: `_/_d_e_v _/_e_t_c _/_p_r_o_c _/_t_m_p _/_v_a_r_/_r_u_n _/_v_a_r_/_t_m_p'
695
696     _._M_A_K_E_._M_E_T_A_._I_G_N_O_R_E___P_A_T_T_E_R_N_S
697             Provides a list of patterns to match against pathnames.  Ignore
698             any that match.
699
700     _._M_A_K_E_._M_E_T_A_._P_R_E_F_I_X
701             Defines the message printed for each meta file updated in "meta
702             verbose" mode.  The default value is:
703                   Building ${.TARGET:H:tA}/${.TARGET:T}
704
705     _._M_A_K_E_._M_O_D_E
706             Processed after reading all makefiles.  Affects the mode that
707             bbmmaakkee runs in.  It can contain these keywords:
708
709             ccoommppaatt  Like --BB, puts bbmmaakkee into "compat" mode.
710
711             mmeettaa    Puts bbmmaakkee into "meta" mode, where meta files are created
712                     for each target to capture the commands run, the output
713                     generated, and if filemon(4) is available, the system
714                     calls which are of interest to bbmmaakkee.  The captured
715                     output can be useful when diagnosing errors.
716
717                     bbmmaakkee will use the information in the meta file to help
718                     determine if a target is out-of-date when the normal
719                     dependency rules indicate it is not.
720
721                     First, the commands to be executed, will be compared to
722                     those captured previously, if any differ, the target is
723                     out-of-date.
724
725                     This allows for a huge improvement in the reliability and
726                     efficiency of update builds.  It is no longer necessary
727                     for targets to depend on makefiles just in-case they set
728                     a variable that might be relevant.  Mechanisms such as
729                     _._M_A_K_E_._M_E_T_A_._C_M_P___F_I_L_T_E_R and ..NNOOMMEETTAA__CCMMPP, allow limiting or
730                     disabling that comparison on a per target basis.  A
731                     reference to the variable _._O_O_D_A_T_E can be leveraged to
732                     block comparison of certain commands.  For example:
733                     `${.OODATE:M}' will expand to nothing and have no impact
734                     on the target, its side-effect though, will be to prevent
735                     comparison of any command line it appears on.  For
736                     documentation purposes `${.OODATE:MNOMETA_CMP}' is
737                     useful.
738
739                     If necessary, bbmmaakkee will then use the information
740                     captured by filemon(4), to check the modification time of
741                     any file used in generating the target, if any is newer,
742                     the target is out-of-date.
743
744                     Such deep inspection can easily lead to cases where a
745                     target is _a_l_w_a_y_s considered out-of-date, which is why
746                     _._M_A_K_E_._M_E_T_A_._I_G_N_O_R_E___F_I_L_T_E_R, _._M_A_K_E_._M_E_T_A_._I_G_N_O_R_E___P_A_T_H_S and
747                     _._M_A_K_E_._M_E_T_A_._I_G_N_O_R_E___P_A_T_T_E_R_N_S, are provided to limit that
748                     inspection when necessary.
749
750             ccuurrddiirrOOkk==_b_f
751                     By default, bbmmaakkee does not create _._m_e_t_a files in
752                     `_._C_U_R_D_I_R'.  This can be overridden by setting _b_f to a
753                     value which represents true.
754
755             mmiissssiinngg--mmeettaa==_b_f
756                     If _b_f is true, a missing _._m_e_t_a file makes the target out-
757                     of-date.
758
759             mmiissssiinngg--ffiilleemmoonn==_b_f
760                     If _b_f is true, missing filemon data makes the target out-
761                     of-date.
762
763             nnooffiilleemmoonn
764                     Do not use filemon(4).
765
766             eennvv     For debugging, it can be useful to include the
767                     environment in the _._m_e_t_a file.
768
769             vveerrbboossee
770                     If in "meta" mode, print a clue about the target being
771                     built.  This is useful if the build is otherwise running
772                     silently.  The message printed is the expanded value of
773                     _._M_A_K_E_._M_E_T_A_._P_R_E_F_I_X.
774
775             iiggnnoorree--ccmmdd
776                     Some makefiles have commands which are simply not stable.
777                     This keyword causes them to be ignored for determining
778                     whether a target is out of date in "meta" mode.  See also
779                     ..NNOOMMEETTAA__CCMMPP.
780
781             ssiilleenntt==_b_f
782                     If _b_f is true, when a .meta file is created, mark the
783                     target ..SSIILLEENNTT.
784
785             rraannddoommiizzee--ttaarrggeettss
786                     In both compat and parallel mode, do not make the targets
787                     in the usual order, but instead randomize their order.
788                     This mode can be used to detect undeclared dependencies
789                     between files.
790
791     _M_A_K_E_O_B_J_D_I_R
792             Used to create files in a separate directory, see _._O_B_J_D_I_R.
793
794     _M_A_K_E___O_B_J_D_I_R___C_H_E_C_K___W_R_I_T_A_B_L_E
795             When true, bbmmaakkee will check that _._O_B_J_D_I_R is writable, and issue a
796             warning if not.
797
798     _M_A_K_E___D_E_B_U_G___O_B_J_D_I_R___C_H_E_C_K___W_R_I_T_A_B_L_E
799             When true and bbmmaakkee is warning about an unwritable _._O_B_J_D_I_R,
800             report the variables listed in _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R to help
801             debug.
802
803     _M_A_K_E_O_B_J_D_I_R_P_R_E_F_I_X
804             Used to create files in a separate directory, see _._O_B_J_D_I_R.  It
805             should be an absolute path.
806
807     _._M_A_K_E_._O_S
808             The name of the operating system, see uname(1).  It is read-only.
809
810     _._M_A_K_E_O_V_E_R_R_I_D_E_S
811             This variable is used to record the names of variables assigned
812             to on the command line, so that they may be exported as part of
813             `MAKEFLAGS'.  This behavior can be disabled by assigning an empty
814             value to `_._M_A_K_E_O_V_E_R_R_I_D_E_S' within a makefile.  Extra variables can
815             be exported from a makefile by appending their names to
816             `_._M_A_K_E_O_V_E_R_R_I_D_E_S'.  `MAKEFLAGS' is re-exported whenever
817             `_._M_A_K_E_O_V_E_R_R_I_D_E_S' is modified.
818
819     _._M_A_K_E_._P_A_T_H___F_I_L_E_M_O_N
820             If bbmmaakkee was built with filemon(4) support, this is set to the
821             path of the device node.  This allows makefiles to test for this
822             support.
823
824     _._M_A_K_E_._P_I_D
825             The process ID of bbmmaakkee.  It is read-only.
826
827     _._M_A_K_E_._P_P_I_D
828             The parent process ID of bbmmaakkee.  It is read-only.
829
830     _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R
831             When bbmmaakkee stops due to an error, it sets `_._E_R_R_O_R___T_A_R_G_E_T' to the
832             name of the target that failed, `_._E_R_R_O_R___E_X_I_T' to the exit status
833             of the failed target, `_._E_R_R_O_R___C_M_D' to the commands of the failed
834             target, and in "meta" mode, it also sets `_._E_R_R_O_R___C_W_D' to the
835             getcwd(3), and `_._E_R_R_O_R___M_E_T_A___F_I_L_E' to the path of the meta file
836             (if any) describing the failed target.  It then prints its name
837             and the value of `_._C_U_R_D_I_R' as well as the value of any variables
838             named in `_M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R'.
839
840     _._M_A_K_E_._S_A_V_E___D_O_L_L_A_R_S
841             If true, `$$' are preserved when doing `:=' assignments.  The
842             default is false, for backwards compatibility.  Set to true for
843             compatability with other makes.  If set to false, `$$' becomes
844             `$' per normal evaluation rules.
845
846     _._M_A_K_E_._T_A_R_G_E_T___L_O_C_A_L___V_A_R_I_A_B_L_E_S
847             If set to `false', apparent variable assignments in dependency
848             lines are treated as normal sources.
849
850     _._M_A_K_E_._U_I_D
851             The numeric ID of the user running bbmmaakkee.  It is read-only.
852
853     _._n_e_w_l_i_n_e
854             This variable is simply assigned a newline character as its
855             value.  It is read-only.  This allows expansions using the ::@@
856             modifier to put a newline between iterations of the loop rather
857             than a space.  For example, in case of an error, bbmmaakkee prints the
858             variable names and their values using:
859                   ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
860
861     _._O_B_J_D_I_R
862             A path to the directory where the targets are built.  Its value
863             is determined by trying to chdir(2) to the following directories
864             in order and using the first match:
865
866             1.   $${{MMAAKKEEOOBBJJDDIIRRPPRREEFFIIXX}}$${{..CCUURRDDIIRR}}
867
868                  (Only if `MAKEOBJDIRPREFIX' is set in the environment or on
869                  the command line.)
870
871             2.   $${{MMAAKKEEOOBBJJDDIIRR}}
872
873                  (Only if `MAKEOBJDIR' is set in the environment or on the
874                  command line.)
875
876             3.   $${{..CCUURRDDIIRR}}_/_o_b_j_.$${{MMAACCHHIINNEE}}
877
878             4.   $${{..CCUURRDDIIRR}}_/_o_b_j
879
880             5.   _/_u_s_r_/_o_b_j_/$${{..CCUURRDDIIRR}}
881
882             6.   $${{..CCUURRDDIIRR}}
883
884             Variable expansion is performed on the value before it is used,
885             so expressions such as $${{..CCUURRDDIIRR::SS,,^^//uussrr//ssrrcc,,//vvaarr//oobbjj,,}} may be
886             used.  This is especially useful with `MAKEOBJDIR'.
887
888             `_._O_B_J_D_I_R' may be modified in the makefile via the special target
889             `..OOBBJJDDIIRR'.  In all cases, bbmmaakkee changes to the specified
890             directory if it exists, and sets `_._O_B_J_D_I_R' and `_P_W_D' to that
891             directory before executing any targets.
892
893             Except in the case of an explicit `..OOBBJJDDIIRR' target, bbmmaakkee checks
894             that the specified directory is writable and ignores it if not.
895             This check can be skipped by setting the environment variable
896             `MAKE_OBJDIR_CHECK_WRITABLE' to "no".
897
898     _._P_A_R_S_E_D_I_R
899             The directory name of the current makefile being parsed.
900
901     _._P_A_R_S_E_F_I_L_E
902             The basename of the current makefile being parsed.  This variable
903             and `_._P_A_R_S_E_D_I_R' are both set only while the makefiles are being
904             parsed.  To retain their current values, assign them to a
905             variable using assignment with expansion `::=='.
906
907     _._P_A_T_H   The space-separated list of directories that bbmmaakkee searches for
908             files.  To update this search list, use the special target
909             `..PPAATTHH' rather than modifying the variable directly.
910
911     _%_P_O_S_I_X  Is set in POSIX mode, see the special `_._P_O_S_I_X' target.
912
913     _P_W_D     Alternate path to the current directory.  bbmmaakkee normally sets
914             `_._C_U_R_D_I_R' to the canonical path given by getcwd(3).  However, if
915             the environment variable `PWD' is set and gives a path to the
916             current directory, bbmmaakkee sets `_._C_U_R_D_I_R' to the value of `PWD'
917             instead.  This behavior is disabled if `MAKEOBJDIRPREFIX' is set
918             or `MAKEOBJDIR' contains a variable transform.  `_P_W_D' is set to
919             the value of `_._O_B_J_D_I_R' for all programs which bbmmaakkee executes.
920
921     _._S_H_E_L_L  The pathname of the shell used to run target scripts.  It is
922             read-only.
923
924     _._S_U_F_F_I_X_E_S
925             The list of known suffixes.  It is read-only.
926
927     _._S_Y_S_P_A_T_H
928             The space-separated list of directories that bbmmaakkee searches for
929             makefiles, referred to as the system include path.  To update
930             this search list, use the special target `..SSYYSSPPAATTHH' rather than
931             modifying the variable which is read-only.
932
933     _._T_A_R_G_E_T_S
934             The list of targets explicitly specified on the command line, if
935             any.
936
937     _V_P_A_T_H   The colon-separated (":") list of directories that bbmmaakkee searches
938             for files.  This variable is supported for compatibility with old
939             make programs only, use `_._P_A_T_H' instead.
940
941   VVaarriiaabbllee mmooddiiffiieerrss
942     The general format of a variable expansion is:
943
944           $${{_v_a_r_i_a_b_l_e[::_m_o_d_i_f_i_e_r[::...]]}}
945
946     Each modifier begins with a colon.  To escape a colon, precede it with a
947     backslash `\'.
948
949     A list of indirect modifiers can be specified via a variable, as follows:
950
951           _m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e = _m_o_d_i_f_i_e_r[::...]
952
953           $${{_v_a_r_i_a_b_l_e::$${{_m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e}}[::...]}}
954
955     In this case, the first modifier in the _m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e does not start
956     with a colon, since that colon already occurs in the referencing
957     variable.  If any of the modifiers in the _m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e contains a
958     dollar sign (`$'), these must be doubled to avoid early expansion.
959
960     Some modifiers interpret the expression value as a single string, others
961     treat the expression value as a whitespace-separated list of words.  When
962     splitting a string into words, whitespace can be escaped using double
963     quotes, single quotes and backslashes, like in the shell.  The quotes and
964     backslashes are retained in the words.
965
966     The supported modifiers are:
967
968     ::EE   Replaces each word with its suffix.
969
970     ::HH   Replaces each word with its dirname.
971
972     ::MM_p_a_t_t_e_r_n
973          Selects only those words that match _p_a_t_t_e_r_n.  The standard shell
974          wildcard characters (`*', `?', and `[]') may be used.  The wildcard
975          characters may be escaped with a backslash (`\').  As a consequence
976          of the way values are split into words, matched, and then joined,
977          the construct `${VAR:M*}' removes all leading and trailing
978          whitespace and normalizes the inter-word spacing to a single space.
979
980     ::NN_p_a_t_t_e_r_n
981          This is the opposite of `::MM', selecting all words which do _n_o_t match
982          _p_a_t_t_e_r_n.
983
984     ::OO   Orders the words lexicographically.
985
986     ::OOnn  Orders the words numerically.  A number followed by one of `k', `M'
987          or `G' is multiplied by the appropriate factor, which is 1024 for
988          `k', 1048576 for `M', or 1073741824 for `G'.  Both upper- and lower-
989          case letters are accepted.
990
991     ::OOrr  Orders the words in reverse lexicographical order.
992
993     ::OOrrnn
994          Orders the words in reverse numerical order.
995
996     ::OOxx  Shuffles the words.  The results are different each time you are
997          referring to the modified variable; use the assignment with
998          expansion `::==' to prevent such behavior.  For example,
999
1000                LIST=                   uno due tre quattro
1001                RANDOM_LIST=            ${LIST:Ox}
1002                STATIC_RANDOM_LIST:=    ${LIST:Ox}
1003
1004                all:
1005                        @echo "${RANDOM_LIST}"
1006                        @echo "${RANDOM_LIST}"
1007                        @echo "${STATIC_RANDOM_LIST}"
1008                        @echo "${STATIC_RANDOM_LIST}"
1009          may produce output similar to:
1010
1011                quattro due tre uno
1012                tre due quattro uno
1013                due uno quattro tre
1014                due uno quattro tre
1015
1016     ::QQ   Quotes every shell meta-character in the value, so that it can be
1017          passed safely to the shell.
1018
1019     ::qq   Quotes every shell meta-character in the value, and also doubles `$'
1020          characters so that it can be passed safely through recursive
1021          invocations of bbmmaakkee.  This is equivalent to `::SS//\\$$//&&&&//gg::QQ'.
1022
1023     ::RR   Replaces each word with everything but its suffix.
1024
1025     ::rraannggee[==_c_o_u_n_t]
1026          The value is an integer sequence representing the words of the
1027          original value, or the supplied _c_o_u_n_t.
1028
1029     ::ggmmttiimmee[==_t_i_m_e_s_t_a_m_p]
1030          The value is interpreted as a format string for strftime(3), using
1031          gmtime(3), producing the formatted timestamp.  Note: the `%s' format
1032          should only be used with `::llooccaallttiimmee'.  If a _t_i_m_e_s_t_a_m_p value is not
1033          provided or is 0, the current time is used.
1034
1035     ::hhaasshh
1036          Computes a 32-bit hash of the value and encodes it as 8 hex digits.
1037
1038     ::llooccaallttiimmee[==_t_i_m_e_s_t_a_m_p]
1039          The value is interpreted as a format string for strftime(3), using
1040          localtime(3), producing the formatted timestamp.  If a _t_i_m_e_s_t_a_m_p
1041          value is not provided or is 0, the current time is used.
1042
1043     ::mmttiimmee[==_t_i_m_e_s_t_a_m_p]
1044          Call stat(2) with each word as pathname; use `st_mtime' as the new
1045          value.  If stat(2) fails; use _t_i_m_e_s_t_a_m_p or current time.  If
1046          _t_i_m_e_s_t_a_m_p is set to `error', then stat(2) failure will cause an
1047          error.
1048
1049     ::ttAA  Attempts to convert the value to an absolute path using realpath(3).
1050          If that fails, the value is unchanged.
1051
1052     ::ttll  Converts the value to lower-case letters.
1053
1054     ::ttss_c
1055          When joining the words after a modifier that treats the value as
1056          words, the words are normally separated by a space.  This modifier
1057          changes the separator to the character _c.  If _c is omitted, no
1058          separator is used.  The common escapes (including octal numeric
1059          codes) work as expected.
1060
1061     ::tttt  Converts the first character of each word to upper-case, and the
1062          rest to lower-case letters.
1063
1064     ::ttuu  Converts the value to upper-case letters.
1065
1066     ::ttWW  Causes subsequent modifiers to treat the value as a single word
1067          (possibly containing embedded whitespace).  See also `::[[**]]'.
1068
1069     ::ttww  Causes the value to be treated as a list of words.  See also `::[[@@]]'.
1070
1071     ::SS/_o_l_d___s_t_r_i_n_g/_n_e_w___s_t_r_i_n_g/[11ggWW]
1072          Modifies the first occurrence of _o_l_d___s_t_r_i_n_g in each word of the
1073          value, replacing it with _n_e_w___s_t_r_i_n_g.  If a `g' is appended to the
1074          last delimiter of the pattern, all occurrences in each word are
1075          replaced.  If a `1' is appended to the last delimiter of the
1076          pattern, only the first occurrence is affected.  If a `W' is
1077          appended to the last delimiter of the pattern, the value is treated
1078          as a single word.  If _o_l_d___s_t_r_i_n_g begins with a caret (`^'),
1079          _o_l_d___s_t_r_i_n_g is anchored at the beginning of each word.  If _o_l_d___s_t_r_i_n_g
1080          ends with a dollar sign (`$'), it is anchored at the end of each
1081          word.  Inside _n_e_w___s_t_r_i_n_g, an ampersand (`&') is replaced by
1082          _o_l_d___s_t_r_i_n_g (without the anchoring `^' or `$').  Any character may be
1083          used as the delimiter for the parts of the modifier string.  The
1084          anchoring, ampersand and delimiter characters can be escaped with a
1085          backslash (`\').
1086
1087          Both _o_l_d___s_t_r_i_n_g and _n_e_w___s_t_r_i_n_g may contain nested expressions.  To
1088          prevent a dollar sign from starting a nested expression, escape it
1089          with a backslash.
1090
1091     ::CC/_p_a_t_t_e_r_n/_r_e_p_l_a_c_e_m_e_n_t/[11ggWW]
1092          The ::CC modifier works like the ::SS modifier except that the old and
1093          new strings, instead of being simple strings, are an extended
1094          regular expression _p_a_t_t_e_r_n (see regex(3)) and an ed(1)-style
1095          _r_e_p_l_a_c_e_m_e_n_t.  Normally, the first occurrence of the pattern _p_a_t_t_e_r_n
1096          in each word of the value is substituted with _r_e_p_l_a_c_e_m_e_n_t.  The `1'
1097          modifier causes the substitution to apply to at most one word; the
1098          `g' modifier causes the substitution to apply to as many instances
1099          of the search pattern _p_a_t_t_e_r_n as occur in the word or words it is
1100          found in; the `W' modifier causes the value to be treated as a
1101          single word (possibly containing embedded whitespace).
1102
1103          As for the ::SS modifier, the _p_a_t_t_e_r_n and _r_e_p_l_a_c_e_m_e_n_t are subjected to
1104          variable expansion before being parsed as regular expressions.
1105
1106     ::TT   Replaces each word with its last path component (basename).
1107
1108     ::uu   Removes adjacent duplicate words (like uniq(1)).
1109
1110     ::??_t_r_u_e___s_t_r_i_n_g::_f_a_l_s_e___s_t_r_i_n_g
1111          If the variable name (not its value), when parsed as a ..iiff
1112          conditional expression, evaluates to true, return as its value the
1113          _t_r_u_e___s_t_r_i_n_g, otherwise return the _f_a_l_s_e___s_t_r_i_n_g.  Since the variable
1114          name is used as the expression, :? must be the first modifier after
1115          the variable name itself--which, of course, usually contains
1116          variable expansions.  A common error is trying to use expressions
1117          like
1118                ${NUMBERS:M42:?match:no}
1119          which actually tests defined(NUMBERS).  To determine if any words
1120          match "42", you need to use something like:
1121                ${"${NUMBERS:M42}" != "":?match:no}.
1122
1123     ::_o_l_d___s_t_r_i_n_g==_n_e_w___s_t_r_i_n_g
1124          This is the AT&T System V UNIX style substitution.  It can only be
1125          the last modifier specified, as a `:' in either _o_l_d___s_t_r_i_n_g or
1126          _n_e_w___s_t_r_i_n_g is treated as a regular character, not as the end of the
1127          modifier.
1128
1129          If _o_l_d___s_t_r_i_n_g does not contain the pattern matching character `%',
1130          and the word ends with _o_l_d___s_t_r_i_n_g or equals it, that suffix is
1131          replaced with _n_e_w___s_t_r_i_n_g.
1132
1133          Otherwise, the first `%' in _o_l_d___s_t_r_i_n_g matches a possibly empty
1134          substring of arbitrary characters, and if the whole pattern is found
1135          in the word, the matching part is replaced with _n_e_w___s_t_r_i_n_g, and the
1136          first occurrence of `%' in _n_e_w___s_t_r_i_n_g (if any) is replaced with the
1137          substring matched by the `%'.
1138
1139          Both _o_l_d___s_t_r_i_n_g and _n_e_w___s_t_r_i_n_g may contain nested expressions.  To
1140          prevent a dollar sign from starting a nested expression, escape it
1141          with a backslash.
1142
1143     ::@@_v_a_r_n_a_m_e@@_s_t_r_i_n_g@@
1144          This is the loop expansion mechanism from the OSF Development
1145          Environment (ODE) make.  Unlike ..ffoorr loops, expansion occurs at the
1146          time of reference.  For each word in the value, assign the word to
1147          the variable named _v_a_r_n_a_m_e and evaluate _s_t_r_i_n_g.  The ODE convention
1148          is that _v_a_r_n_a_m_e should start and end with a period, for example:
1149                ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1150
1151          However, a single-letter variable is often more readable:
1152                ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1153
1154     ::__[==_v_a_r]
1155          Saves the current variable value in `$_' or the named _v_a_r for later
1156          reference.  Example usage:
1157
1158                M_cmpv.units = 1 1000 1000000
1159                M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \
1160                \* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh
1161
1162                .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}
1163
1164          Here `$_' is used to save the result of the `:S' modifier which is
1165          later referenced using the index values from `:range'.
1166
1167     ::UU_n_e_w_v_a_l
1168          If the variable is undefined, the optional _n_e_w_v_a_l (which may be
1169          empty) is the value.  If the variable is defined, the existing value
1170          is returned.  This is another ODE make feature.  It is handy for
1171          setting per-target CFLAGS for instance:
1172                ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1173          If a value is only required if the variable is undefined, use:
1174                ${VAR:D:Unewval}
1175
1176     ::DD_n_e_w_v_a_l
1177          If the variable is defined, _n_e_w_v_a_l (which may be empty) is the
1178          value.
1179
1180     ::LL   The name of the variable is the value.
1181
1182     ::PP   The path of the node which has the same name as the variable is the
1183          value.  If no such node exists or its path is null, the name of the
1184          variable is used.  In order for this modifier to work, the name
1185          (node) must at least have appeared on the right-hand side of a
1186          dependency.
1187
1188     ::!!_c_m_d!!
1189          The output of running _c_m_d is the value.
1190
1191     ::sshh  The value is run as a command, and the output becomes the new value.
1192
1193     ::::==_s_t_r
1194          The variable is assigned the value _s_t_r after substitution.  This
1195          modifier and its variations are useful in obscure situations such as
1196          wanting to set a variable at a point where a target's shell commands
1197          are being parsed.  These assignment modifiers always expand to
1198          nothing.
1199
1200          The `::::' helps avoid false matches with the AT&T System V UNIX style
1201          `:=' modifier and since substitution always occurs, the `::=' form
1202          is vaguely appropriate.
1203
1204     ::::??==_s_t_r
1205          As for ::::== but only if the variable does not already have a value.
1206
1207     ::::++==_s_t_r
1208          Append _s_t_r to the variable.
1209
1210     ::::!!==_c_m_d
1211          Assign the output of _c_m_d to the variable.
1212
1213     ::[[_r_a_n_g_e]]
1214          Selects one or more words from the value, or performs other
1215          operations related to the way in which the value is split into
1216          words.
1217
1218          An empty value, or a value that consists entirely of white-space, is
1219          treated as a single word.  For the purposes of the `::[[]]' modifier,
1220          the words are indexed both forwards using positive integers (where
1221          index 1 represents the first word), and backwards using negative
1222          integers (where index -1 represents the last word).
1223
1224          The _r_a_n_g_e is subjected to variable expansion, and the expanded
1225          result is then interpreted as follows:
1226
1227          _i_n_d_e_x  Selects a single word from the value.
1228
1229          _s_t_a_r_t...._e_n_d
1230                 Selects all words from _s_t_a_r_t to _e_n_d, inclusive.  For example,
1231                 `::[[22....--11]]' selects all words from the second word to the last
1232                 word.  If _s_t_a_r_t is greater than _e_n_d, the words are output in
1233                 reverse order.  For example, `::[[--11....11]]' selects all the words
1234                 from last to first.  If the list is already ordered, this
1235                 effectively reverses the list, but it is more efficient to
1236                 use `::OOrr' instead of `::OO::[[--11....11]]'.
1237
1238          **      Causes subsequent modifiers to treat the value as a single
1239                 word (possibly containing embedded whitespace).  Analogous to
1240                 the effect of $* in Bourne shell.
1241
1242          0      Means the same as `::[[**]]'.
1243
1244          @@      Causes subsequent modifiers to treat the value as a sequence
1245                 of words delimited by whitespace.  Analogous to the effect of
1246                 $@ in Bourne shell.
1247
1248          ##      Returns the number of words in the value.
1249
1250DDIIRREECCTTIIVVEESS
1251     bbmmaakkee offers directives for including makefiles, conditionals and for
1252     loops.  All these directives are identified by a line beginning with a
1253     single dot (`.') character, followed by the keyword of the directive,
1254     such as iinncclluuddee or iiff.
1255
1256   FFiillee iinncclluussiioonn
1257     Files are included with either ..iinncclluuddee <<_f_i_l_e>> or ..iinncclluuddee ""_f_i_l_e"".
1258     Variables between the angle brackets or double quotes are expanded to
1259     form the file name.  If angle brackets are used, the included makefile is
1260     expected to be in the system makefile directory.  If double quotes are
1261     used, the including makefile's directory and any directories specified
1262     using the --II option are searched before the system makefile directory.
1263
1264     For compatibility with other make variants, `iinncclluuddee _f_i_l_e ...' (without
1265     leading dot) is also accepted.
1266
1267     If the include statement is written as ..--iinncclluuddee or as ..ssiinncclluuddee, errors
1268     locating and/or opening include files are ignored.
1269
1270     If the include statement is written as ..ddiinncclluuddee, not only are errors
1271     locating and/or opening include files ignored, but stale dependencies
1272     within the included file are ignored just like in _._M_A_K_E_._D_E_P_E_N_D_F_I_L_E.
1273
1274   EExxppoorrttiinngg vvaarriiaabblleess
1275     The directives for exporting and unexporting variables are:
1276
1277     ..eexxppoorrtt _v_a_r_i_a_b_l_e ...
1278             Export the specified global variable.
1279
1280             For compatibility with other make programs, eexxppoorrtt _v_a_r_i_a_b_l_e==_v_a_l_u_e
1281             (without leading dot) is also accepted.
1282
1283             Appending a variable name to _._M_A_K_E_._E_X_P_O_R_T_E_D is equivalent to
1284             exporting a variable.
1285
1286     ..eexxppoorrtt--aallll
1287             Export all globals except for internal variables (those that
1288             start with `.').  This is not affected by the --XX flag, so should
1289             be used with caution.
1290
1291     ..eexxppoorrtt--eennvv _v_a_r_i_a_b_l_e ...
1292             The same as `.export', except that the variable is not appended
1293             to _._M_A_K_E_._E_X_P_O_R_T_E_D.  This allows exporting a value to the
1294             environment which is different from that used by bbmmaakkee
1295             internally.
1296
1297     ..eexxppoorrtt--lliitteerraall _v_a_r_i_a_b_l_e ...
1298             The same as `.export-env', except that variables in the value are
1299             not expanded.
1300
1301     ..uunneexxppoorrtt _v_a_r_i_a_b_l_e ...
1302             The opposite of `.export'.  The specified global _v_a_r_i_a_b_l_e is
1303             removed from _._M_A_K_E_._E_X_P_O_R_T_E_D.  If no variable list is provided,
1304             all globals are unexported, and _._M_A_K_E_._E_X_P_O_R_T_E_D deleted.
1305
1306     ..uunneexxppoorrtt--eennvv
1307             Unexport all globals previously exported and clear the
1308             environment inherited from the parent.  This operation causes a
1309             memory leak of the original environment, so should be used
1310             sparingly.  Testing for _._M_A_K_E_._L_E_V_E_L being 0 would make sense.
1311             Also note that any variables which originated in the parent
1312             environment should be explicitly preserved if desired.  For
1313             example:
1314
1315                   .if ${.MAKE.LEVEL} == 0
1316                   PATH := ${PATH}
1317                   .unexport-env
1318                   .export PATH
1319                   .endif
1320
1321             Would result in an environment containing only `PATH', which is
1322             the minimal useful environment.  Actually `_._M_A_K_E_._L_E_V_E_L' is also
1323             pushed into the new environment.
1324
1325   MMeessssaaggeess
1326     The directives for printing messages to the output are:
1327
1328     ..iinnffoo _m_e_s_s_a_g_e
1329             The message is printed along with the name of the makefile and
1330             line number.
1331
1332     ..wwaarrnniinngg _m_e_s_s_a_g_e
1333             The message prefixed by `warning:' is printed along with the name
1334             of the makefile and line number.
1335
1336     ..eerrrroorr _m_e_s_s_a_g_e
1337             The message is printed along with the name of the makefile and
1338             line number, bbmmaakkee exits immediately.
1339
1340   CCoonnddiittiioonnaallss
1341     The directives for conditionals are:
1342
1343     ..iiff [!!]_e_x_p_r_e_s_s_i_o_n [_o_p_e_r_a_t_o_r _e_x_p_r_e_s_s_i_o_n ...]
1344             Test the value of an expression.
1345
1346     ..iiffddeeff [!!]_v_a_r_i_a_b_l_e [_o_p_e_r_a_t_o_r _v_a_r_i_a_b_l_e ...]
1347             Test whether a variable is defined.
1348
1349     ..iiffnnddeeff [!!]_v_a_r_i_a_b_l_e [_o_p_e_r_a_t_o_r _v_a_r_i_a_b_l_e ...]
1350             Test whether a variable is not defined.
1351
1352     ..iiffmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
1353             Test the target being requested.
1354
1355     ..iiffnnmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
1356             Test the target being requested.
1357
1358     ..eellssee   Reverse the sense of the last conditional.
1359
1360     ..eelliiff [!!]_e_x_p_r_e_s_s_i_o_n [_o_p_e_r_a_t_o_r _e_x_p_r_e_s_s_i_o_n ...]
1361             A combination of `..eellssee' followed by `..iiff'.
1362
1363     ..eelliiffddeeff [!!]_v_a_r_i_a_b_l_e [_o_p_e_r_a_t_o_r _v_a_r_i_a_b_l_e ...]
1364             A combination of `..eellssee' followed by `..iiffddeeff'.
1365
1366     ..eelliiffnnddeeff [!!]_v_a_r_i_a_b_l_e [_o_p_e_r_a_t_o_r _v_a_r_i_a_b_l_e ...]
1367             A combination of `..eellssee' followed by `..iiffnnddeeff'.
1368
1369     ..eelliiffmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
1370             A combination of `..eellssee' followed by `..iiffmmaakkee'.
1371
1372     ..eelliiffnnmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
1373             A combination of `..eellssee' followed by `..iiffnnmmaakkee'.
1374
1375     ..eennddiiff  End the body of the conditional.
1376
1377     The _o_p_e_r_a_t_o_r may be any one of the following:
1378
1379     ||||      Logical OR.
1380
1381     &&&&      Logical AND; of higher precedence than `||||'.
1382
1383     bbmmaakkee only evaluates a conditional as far as is necessary to determine
1384     its value.  Parentheses can be used to override the operator precedence.
1385     The boolean operator `!!' may be used to logically negate an expression,
1386     typically a function call.  It is of higher precedence than `&&&&'.
1387
1388     The value of _e_x_p_r_e_s_s_i_o_n may be any of the following function call
1389     expressions:
1390
1391     ddeeffiinneedd(_v_a_r_n_a_m_e)
1392             Evaluates to true if the variable _v_a_r_n_a_m_e has been defined.
1393
1394     mmaakkee(_t_a_r_g_e_t)
1395             Evaluates to true if the target was specified as part of bbmmaakkee's
1396             command line or was declared the default target (either
1397             implicitly or explicitly, see _._M_A_I_N) before the line containing
1398             the conditional.
1399
1400     eemmppttyy(_v_a_r_n_a_m_e[:_m_o_d_i_f_i_e_r_s])
1401             Evaluates to true if the expansion of the variable, after
1402             applying the modifiers, results in an empty string.
1403
1404     eexxiissttss(_p_a_t_h_n_a_m_e)
1405             Evaluates to true if the given pathname exists.  If relative, the
1406             pathname is searched for on the system search path (see _._P_A_T_H).
1407
1408     ttaarrggeett(_t_a_r_g_e_t)
1409             Evaluates to true if the target has been defined.
1410
1411     ccoommmmaannddss(_t_a_r_g_e_t)
1412             Evaluates to true if the target has been defined and has commands
1413             associated with it.
1414
1415     _E_x_p_r_e_s_s_i_o_n may also be an arithmetic or string comparison.  Variable
1416     expansion is performed on both sides of the comparison.  If both sides
1417     are numeric and neither is enclosed in quotes, the comparison is done
1418     numerically, otherwise lexicographically.  A string is interpreted as a
1419     hexadecimal integer if it is preceded by 0x, otherwise it is interpreted
1420     as a decimal floating-point number; octal numbers are not supported.
1421
1422     All comparisons may use the operators `====' and `!!=='.  Numeric comparisons
1423     may also use the operators `<<', `<<==', `>>' and `>>=='.
1424
1425     If the comparison has neither a comparison operator nor a right side, the
1426     expression evaluates to true if it is nonempty and its numeric value (if
1427     any) is not zero.
1428
1429     When bbmmaakkee is evaluating one of these conditional expressions, and it
1430     encounters a (whitespace-separated) word it doesn't recognize, either the
1431     "make" or "defined" function is applied to it, depending on the form of
1432     the conditional.  If the form is `..iiffddeeff', `..iiffnnddeeff' or `..iiff', the
1433     "defined" function is applied.  Similarly, if the form is `..iiffmmaakkee' or
1434     `..iiffnnmmaakkee', the "make" function is applied.
1435
1436     If the conditional evaluates to true, parsing of the makefile continues
1437     as before.  If it evaluates to false, the following lines until the
1438     corresponding `..eelliiff' variant, `..eellssee' or `..eennddiiff' are skipped.
1439
1440   FFoorr llooooppss
1441     For loops are typically used to apply a set of rules to a list of files.
1442     The syntax of a for loop is:
1443
1444     ..ffoorr _v_a_r_i_a_b_l_e [_v_a_r_i_a_b_l_e ...] iinn _e_x_p_r_e_s_s_i_o_n
1445     <_m_a_k_e_-_l_i_n_e_s>
1446     ..eennddffoorr
1447
1448     The _e_x_p_r_e_s_s_i_o_n is expanded and then split into words.  On each iteration
1449     of the loop, one word is taken and assigned to each _v_a_r_i_a_b_l_e, in order,
1450     and these _v_a_r_i_a_b_l_e_s are substituted into the _m_a_k_e_-_l_i_n_e_s inside the body
1451     of the for loop.  The number of words must come out even; that is, if
1452     there are three iteration variables, the number of words provided must be
1453     a multiple of three.
1454
1455     If `..bbrreeaakk' is encountered within a ..ffoorr loop, it causes early
1456     termination of the loop, otherwise a parse error.
1457
1458   OOtthheerr ddiirreeccttiivveess
1459     ..uunnddeeff _v_a_r_i_a_b_l_e ...
1460             Un-define the specified global variables.  Only global variables
1461             can be un-defined.
1462
1463CCOOMMMMEENNTTSS
1464     Comments begin with a hash (`#') character, anywhere but in a shell
1465     command line, and continue to the end of an unescaped new line.
1466
1467SSPPEECCIIAALL SSOOUURRCCEESS ((AATTTTRRIIBBUUTTEESS))
1468     ..EEXXEECC     Target is never out of date, but always execute commands
1469               anyway.
1470
1471     ..IIGGNNOORREE   Ignore any errors from the commands associated with this
1472               target, exactly as if they all were preceded by a dash (`-').
1473
1474     ..MMAADDEE     Mark all sources of this target as being up to date.
1475
1476     ..MMAAKKEE     Execute the commands associated with this target even if the --nn
1477               or --tt options were specified.  Normally used to mark recursive
1478               bbmmaakkees.
1479
1480     ..MMEETTAA     Create a meta file for the target, even if it is flagged as
1481               ..PPHHOONNYY, ..MMAAKKEE, or ..SSPPEECCIIAALL.  Usage in conjunction with ..MMAAKKEE is
1482               the most likely case.  In "meta" mode, the target is out-of-
1483               date if the meta file is missing.
1484
1485     ..NNOOMMEETTAA   Do not create a meta file for the target.  Meta files are also
1486               not created for ..PPHHOONNYY, ..MMAAKKEE, or ..SSPPEECCIIAALL targets.
1487
1488     ..NNOOMMEETTAA__CCMMPP
1489               Ignore differences in commands when deciding if target is out
1490               of date.  This is useful if the command contains a value which
1491               always changes.  If the number of commands change, though, the
1492               target is still considered out of date.  The same effect
1493               applies to any command line that uses the variable _._O_O_D_A_T_E,
1494               which can be used for that purpose even when not otherwise
1495               needed or desired:
1496
1497
1498                     skip-compare-for-some:
1499                             @echo this is compared
1500                             @echo this is not ${.OODATE:M.NOMETA_CMP}
1501                             @echo this is also compared
1502
1503               The ::MM pattern suppresses any expansion of the unwanted
1504               variable.
1505
1506     ..NNOOPPAATTHH   Do not search for the target in the directories specified by
1507               _._P_A_T_H.
1508
1509     ..NNOOTTMMAAIINN  Normally bbmmaakkee selects the first target it encounters as the
1510               default target to be built if no target was specified.  This
1511               source prevents this target from being selected.
1512
1513     ..OOPPTTIIOONNAALL
1514               If a target is marked with this attribute and bbmmaakkee can't
1515               figure out how to create it, it ignores this fact and assumes
1516               the file isn't needed or already exists.
1517
1518     ..PPHHOONNYY    The target does not correspond to an actual file; it is always
1519               considered to be out of date, and is not created with the --tt
1520               option.  Suffix-transformation rules are not applied to ..PPHHOONNYY
1521               targets.
1522
1523     ..PPRREECCIIOOUUSS
1524               When bbmmaakkee is interrupted, it normally removes any partially
1525               made targets.  This source prevents the target from being
1526               removed.
1527
1528     ..RREECCUURRSSIIVVEE
1529               Synonym for ..MMAAKKEE.
1530
1531     ..SSIILLEENNTT   Do not echo any of the commands associated with this target,
1532               exactly as if they all were preceded by an at sign (`@').
1533
1534     ..UUSSEE      Turn the target into bbmmaakkee's version of a macro.  When the
1535               target is used as a source for another target, the other target
1536               acquires the commands, sources, and attributes (except for
1537               ..UUSSEE) of the source.  If the target already has commands, the
1538               ..UUSSEE target's commands are appended to them.
1539
1540     ..UUSSEEBBEEFFOORREE
1541               Like ..UUSSEE, but instead of appending, prepend the ..UUSSEEBBEEFFOORREE
1542               target commands to the target.
1543
1544     ..WWAAIITT     If ..WWAAIITT appears in a dependency line, the sources that precede
1545               it are made before the sources that succeed it in the line.
1546               Since the dependents of files are not made until the file
1547               itself could be made, this also stops the dependents being
1548               built unless they are needed for another branch of the
1549               dependency tree.  So given:
1550
1551               x: a .WAIT b
1552                       echo x
1553               a:
1554                       echo a
1555               b: b1
1556                       echo b
1557               b1:
1558                       echo b1
1559
1560               the output is always `a', `b1', `b', `x'.
1561
1562               The ordering imposed by ..WWAAIITT is only relevant for parallel
1563               makes.
1564
1565SSPPEECCIIAALL TTAARRGGEETTSS
1566     Special targets may not be included with other targets, i.e. they must be
1567     the only target specified.
1568
1569     ..BBEEGGIINN   Any command lines attached to this target are executed before
1570              anything else is done.
1571
1572     ..DDEEFFAAUULLTT
1573              This is sort of a ..UUSSEE rule for any target (that was used only
1574              as a source) that bbmmaakkee can't figure out any other way to
1575              create.  Only the shell script is used.  The _._I_M_P_S_R_C variable of
1576              a target that inherits ..DDEEFFAAUULLTT's commands is set to the
1577              target's own name.
1578
1579     ..DDEELLEETTEE__OONN__EERRRROORR
1580              If this target is present in the makefile, it globally causes
1581              make to delete targets whose commands fail.  (By default, only
1582              targets whose commands are interrupted during execution are
1583              deleted.  This is the historical behavior.)  This setting can be
1584              used to help prevent half-finished or malformed targets from
1585              being left around and corrupting future rebuilds.
1586
1587     ..EENNDD     Any command lines attached to this target are executed after
1588              everything else is done successfully.
1589
1590     ..EERRRROORR   Any command lines attached to this target are executed when
1591              another target fails.  See _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R for the
1592              variables that will be set.
1593
1594     ..IIGGNNOORREE  Mark each of the sources with the ..IIGGNNOORREE attribute.  If no
1595              sources are specified, this is the equivalent of specifying the
1596              --ii option.
1597
1598     ..IINNTTEERRRRUUPPTT
1599              If bbmmaakkee is interrupted, the commands for this target are
1600              executed.
1601
1602     ..MMAAIINN    If no target is specified when bbmmaakkee is invoked, this target is
1603              built.
1604
1605     ..MMAAKKEEFFLLAAGGSS
1606              This target provides a way to specify flags for bbmmaakkee at the
1607              time when the makefiles are read.  The flags are as if typed to
1608              the shell, though the --ff option has no effect.
1609
1610     ..NNOOPPAATTHH  Apply the ..NNOOPPAATTHH attribute to any specified sources.
1611
1612     ..NNOOTTPPAARRAALLLLEELL
1613              Disable parallel mode.
1614
1615     ..NNOO__PPAARRAALLLLEELL
1616              Synonym for ..NNOOTTPPAARRAALLLLEELL, for compatibility with other pmake
1617              variants.
1618
1619     ..NNOORREEAADDOONNLLYY
1620              clear the read-only attribute from the global variables
1621              specified as sources.
1622
1623     ..OOBBJJDDIIRR  The source is a new value for `_._O_B_J_D_I_R'.  If it exists, bbmmaakkee
1624              changes the current working directory to it and updates the
1625              value of `_._O_B_J_D_I_R'.
1626
1627     ..OORRDDEERR   In parallel mode, the named targets are made in sequence.  This
1628              ordering does not add targets to the list of targets to be made.
1629
1630              Since the dependents of a target do not get built until the
1631              target itself could be built, unless `a' is built by another
1632              part of the dependency graph, the following is a dependency
1633              loop:
1634
1635              .ORDER: b a
1636              b: a
1637
1638     ..PPAATTHH    The sources are directories which are to be searched for files
1639              not found in the current directory.  If no sources are
1640              specified, any previously specified directories are removed from
1641              the search path.  If the source is the special ..DDOOTTLLAASSTT target,
1642              the current working directory is searched last.
1643
1644     ..PPAATTHH.._s_u_f_f_i_x
1645              Like ..PPAATTHH but applies only to files with a particular suffix.
1646              The suffix must have been previously declared with ..SSUUFFFFIIXXEESS.
1647
1648     ..PPHHOONNYY   Apply the ..PPHHOONNYY attribute to any specified sources.
1649
1650     ..PPOOSSIIXX   If this is the first non-comment line in the main makefile, the
1651              variable _%_P_O_S_I_X is set to the value `1003.2' and the makefile
1652              `<posix.mk>' is included if it exists, to provide POSIX-
1653              compatible default rules.  If bbmmaakkee is run with the --rr flag,
1654              only `posix.mk' contributes to the default rules.  In POSIX-
1655              compatible mode, the AT&T System V UNIX style substitution
1656              modifier is checked first rather than as a fallback.
1657
1658     ..PPRREECCIIOOUUSS
1659              Apply the ..PPRREECCIIOOUUSS attribute to any specified sources.  If no
1660              sources are specified, the ..PPRREECCIIOOUUSS attribute is applied to
1661              every target in the file.
1662
1663     ..RREEAADDOONNLLYY
1664              set the read-only attribute on the global variables specified as
1665              sources.
1666
1667     ..SSHHEELLLL   Sets the shell that bbmmaakkee uses to execute commands.  The sources
1668              are a set of _f_i_e_l_d==_v_a_l_u_e pairs.
1669
1670              name        This is the minimal specification, used to select
1671                          one of the built-in shell specs; sh, ksh, and csh.
1672
1673              path        Specifies the absolute path to the shell.
1674
1675              hasErrCtl   Indicates whether the shell supports exit on error.
1676
1677              check       The command to turn on error checking.
1678
1679              ignore      The command to disable error checking.
1680
1681              echo        The command to turn on echoing of commands executed.
1682
1683              quiet       The command to turn off echoing of commands
1684                          executed.
1685
1686              filter      The output to filter after issuing the quiet
1687                          command.  It is typically identical to quiet.
1688
1689              errFlag     The flag to pass the shell to enable error checking.
1690
1691              echoFlag    The flag to pass the shell to enable command
1692                          echoing.
1693
1694              newline     The string literal to pass the shell that results in
1695                          a single newline character when used outside of any
1696                          quoting characters.
1697              Example:
1698
1699              .SHELL: name=ksh path=/bin/ksh hasErrCtl=true \
1700                      check="set -e" ignore="set +e" \
1701                      echo="set -v" quiet="set +v" filter="set +v" \
1702                      echoFlag=v errFlag=e newline="'\n'"
1703
1704     ..SSIILLEENNTT  Apply the ..SSIILLEENNTT attribute to any specified sources.  If no
1705              sources are specified, the ..SSIILLEENNTT attribute is applied to every
1706              command in the file.
1707
1708     ..SSTTAALLEE   This target gets run when a dependency file contains stale
1709              entries, having _._A_L_L_S_R_C set to the name of that dependency file.
1710
1711     ..SSUUFFFFIIXXEESS
1712              Each source specifies a suffix to bbmmaakkee.  If no sources are
1713              specified, any previously specified suffixes are deleted.  It
1714              allows the creation of suffix-transformation rules.
1715
1716              Example:
1717
1718              .SUFFIXES: .c .o
1719              .c.o:
1720                      cc -o ${.TARGET} -c ${.IMPSRC}
1721
1722     ..SSYYSSPPAATTHH
1723              The sources are directories which are to be added to the system
1724              include path which bbmmaakkee searches for makefiles.  If no sources
1725              are specified, any previously specified directories are removed
1726              from the system include path.
1727
1728EENNVVIIRROONNMMEENNTT
1729     bbmmaakkee uses the following environment variables, if they exist: MACHINE,
1730     MACHINE_ARCH, MAKE, MAKEFLAGS, MAKEOBJDIR, MAKEOBJDIRPREFIX, MAKESYSPATH,
1731     MAKE_STACK_TRACE, PWD, and TMPDIR.
1732
1733     MAKEOBJDIRPREFIX and MAKEOBJDIR should be set in the environment or on
1734     the command line to bbmmaakkee and not as makefile variables; see the
1735     description of `_._O_B_J_D_I_R' for more details.  It is possible to set these
1736     via makefile variables but unless done very early and the `..OOBBJJDDIIRR'
1737     target is used to reset `_._O_B_J_D_I_R', there may be unexpected side effects.
1738
1739     If the MAKE_STACK_TRACE environment variable is set to "yes", any stack
1740     traces include the call chain of the parent processes.
1741
1742FFIILLEESS
1743     .depend        list of dependencies
1744     makefile       first default makefile if no makefile is specified on the
1745                    command line
1746     Makefile       second default makefile if no makefile is specified on the
1747                    command line
1748     sys.mk         system makefile
1749     /usr/share/mk  system makefile directory
1750
1751CCOOMMPPAATTIIBBIILLIITTYY
1752     The basic make syntax is compatible between different make variants;
1753     however the special variables, variable modifiers and conditionals are
1754     not.
1755
1756   OOllddeerr vveerrssiioonnss
1757     An incomplete list of changes in older versions of bbmmaakkee:
1758
1759     The way that .for loop variables are substituted changed after NetBSD 5.0
1760     so that they still appear to be variable expansions.  In particular this
1761     stops them being treated as syntax, and removes some obscure problems
1762     using them in .if statements.
1763
1764     The way that parallel makes are scheduled changed in NetBSD 4.0 so that
1765     .ORDER and .WAIT apply recursively to the dependent nodes.  The
1766     algorithms used may change again in the future.
1767
1768   OOtthheerr mmaakkee ddiiaalleeccttss
1769     Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
1770     support most of the features of bbmmaakkee as described in this manual.  Most
1771     notably:
1772
1773           ++oo   The ..WWAAIITT and ..OORRDDEERR declarations and most functionality
1774               pertaining to parallelization.  (GNU make supports
1775               parallelization but lacks the features needed to control it
1776               effectively.)
1777
1778           ++oo   Directives, including for loops and conditionals and most of
1779               the forms of include files.  (GNU make has its own incompatible
1780               and less powerful syntax for conditionals.)
1781
1782           ++oo   All built-in variables that begin with a dot.
1783
1784           ++oo   Most of the special sources and targets that begin with a dot,
1785               with the notable exception of ..PPHHOONNYY, ..PPRREECCIIOOUUSS, and ..SSUUFFFFIIXXEESS.
1786
1787           ++oo   Variable modifiers, except for the `:old=new' string
1788               substitution, which does not portably support globbing with `%'
1789               and historically only works on declared suffixes.
1790
1791           ++oo   The $$>> variable even in its short form; most makes support this
1792               functionality but its name varies.
1793
1794     Some features are somewhat more portable, such as assignment with ++==, ??==,
1795     and !!==.  The _._P_A_T_H functionality is based on an older feature VVPPAATTHH found
1796     in GNU make and many versions of SVR4 make; however, historically its
1797     behavior is too ill-defined (and too buggy) to rely upon.
1798
1799     The $$@@ and $$<< variables are more or less universally portable, as is the
1800     $$((MMAAKKEE)) variable.  Basic use of suffix rules (for files only in the
1801     current directory, not trying to chain transformations together, etc.) is
1802     also reasonably portable.
1803
1804SSEEEE AALLSSOO
1805     mkdep(1)
1806
1807HHIISSTTOORRYY
1808     bbmmaakkee is derived from NetBSD make(1).  It uses autoconf to facilitate
1809     portability to other platforms.
1810
1811     A make command appeared in Version 7 AT&T UNIX.  This make implementation
1812     is based on Adam de Boor's pmake program, which was written for Sprite at
1813     Berkeley.  It was designed to be a parallel distributed make running jobs
1814     on different machines using a daemon called "customs".
1815
1816     Historically the target/dependency FFRRCC has been used to FoRCe rebuilding
1817     (since the target/dependency does not exist ... unless someone creates an
1818     _F_R_C file).
1819
1820BBUUGGSS
1821     The bbmmaakkee syntax is difficult to parse.  For instance, finding the end of
1822     a variable's use should involve scanning each of the modifiers, using the
1823     correct terminator for each field.  In many places bbmmaakkee just counts {}
1824     and () in order to find the end of a variable expansion.
1825
1826     There is no way of escaping a space character in a filename.
1827
1828     In jobs mode, when a target fails; bbmmaakkee will put an error token into the
1829     job token pool.  This will cause all other instances of bbmmaakkee using that
1830     token pool to abort the build and exit with error code 6.  Sometimes the
1831     attempt to suppress a cascade of unnecessary errors, can result in a
1832     seemingly unexplained `*** Error code 6'
1833
1834FreeBSD 14.2-RELEASE-p1          June 12, 2025         FreeBSD 14.2-RELEASE-p1
1835