xref: /freebsd/contrib/bmake/bmake.cat1 (revision 6a7405f5a6b639682cacf01e35d561411ff556aa)
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 command 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             ccuurrddiirrOOkk==_b_f
718                     By default, bbmmaakkee does not create _._m_e_t_a files in
719                     `_._C_U_R_D_I_R'.  This can be overridden by setting _b_f to a
720                     value which represents true.
721
722             mmiissssiinngg--mmeettaa==_b_f
723                     If _b_f is true, a missing _._m_e_t_a file makes the target out-
724                     of-date.
725
726             mmiissssiinngg--ffiilleemmoonn==_b_f
727                     If _b_f is true, missing filemon data makes the target out-
728                     of-date.
729
730             nnooffiilleemmoonn
731                     Do not use filemon(4).
732
733             eennvv     For debugging, it can be useful to include the
734                     environment in the _._m_e_t_a file.
735
736             vveerrbboossee
737                     If in "meta" mode, print a clue about the target being
738                     built.  This is useful if the build is otherwise running
739                     silently.  The message printed is the expanded value of
740                     _._M_A_K_E_._M_E_T_A_._P_R_E_F_I_X.
741
742             iiggnnoorree--ccmmdd
743                     Some makefiles have commands which are simply not stable.
744                     This keyword causes them to be ignored for determining
745                     whether a target is out of date in "meta" mode.  See also
746                     ..NNOOMMEETTAA__CCMMPP.
747
748             ssiilleenntt==_b_f
749                     If _b_f is true, when a .meta file is created, mark the
750                     target ..SSIILLEENNTT.
751
752             rraannddoommiizzee--ttaarrggeettss
753                     In both compat and parallel mode, do not make the targets
754                     in the usual order, but instead randomize their order.
755                     This mode can be used to detect undeclared dependencies
756                     between files.
757
758     _M_A_K_E_O_B_J_D_I_R
759             Used to create files in a separate directory, see _._O_B_J_D_I_R.
760
761     _M_A_K_E___O_B_J_D_I_R___C_H_E_C_K___W_R_I_T_A_B_L_E
762             When true, bbmmaakkee will check that _._O_B_J_D_I_R is writable, and issue a
763             warning if not.
764
765     _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
766             When true and bbmmaakkee is warning about an unwritable _._O_B_J_D_I_R,
767             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
768             debug.
769
770     _M_A_K_E_O_B_J_D_I_R_P_R_E_F_I_X
771             Used to create files in a separate directory, see _._O_B_J_D_I_R.  It
772             should be an absolute path.
773
774     _._M_A_K_E_._O_S
775             The name of the operating system, see uname(1).  It is read-only.
776
777     _._M_A_K_E_O_V_E_R_R_I_D_E_S
778             This variable is used to record the names of variables assigned
779             to on the command line, so that they may be exported as part of
780             `MAKEFLAGS'.  This behavior can be disabled by assigning an empty
781             value to `_._M_A_K_E_O_V_E_R_R_I_D_E_S' within a makefile.  Extra variables can
782             be exported from a makefile by appending their names to
783             `_._M_A_K_E_O_V_E_R_R_I_D_E_S'.  `MAKEFLAGS' is re-exported whenever
784             `_._M_A_K_E_O_V_E_R_R_I_D_E_S' is modified.
785
786     _._M_A_K_E_._P_A_T_H___F_I_L_E_M_O_N
787             If bbmmaakkee was built with filemon(4) support, this is set to the
788             path of the device node.  This allows makefiles to test for this
789             support.
790
791     _._M_A_K_E_._P_I_D
792             The process ID of bbmmaakkee.  It is read-only.
793
794     _._M_A_K_E_._P_P_I_D
795             The parent process ID of bbmmaakkee.  It is read-only.
796
797     _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R
798             When bbmmaakkee stops due to an error, it sets `_._E_R_R_O_R___T_A_R_G_E_T' to the
799             name of the target that failed, `_._E_R_R_O_R___E_X_I_T' to the exit status
800             of the failed target, `_._E_R_R_O_R___C_M_D' to the commands of the failed
801             target, and in "meta" mode, it also sets `_._E_R_R_O_R___C_W_D' to the
802             getcwd(3), and `_._E_R_R_O_R___M_E_T_A___F_I_L_E' to the path of the meta file
803             (if any) describing the failed target.  It then prints its name
804             and the value of `_._C_U_R_D_I_R' as well as the value of any variables
805             named in `_M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R'.
806
807     _._M_A_K_E_._S_A_V_E___D_O_L_L_A_R_S
808             If true, `$$' are preserved when doing `:=' assignments.  The
809             default is false, for backwards compatibility.  Set to true for
810             compatability with other makes.  If set to false, `$$' becomes
811             `$' per normal evaluation rules.
812
813     _._M_A_K_E_._T_A_R_G_E_T___L_O_C_A_L___V_A_R_I_A_B_L_E_S
814             If set to `false', apparent variable assignments in dependency
815             lines are treated as normal sources.
816
817     _._M_A_K_E_._U_I_D
818             The numeric ID of the user running bbmmaakkee.  It is read-only.
819
820     _._n_e_w_l_i_n_e
821             This variable is simply assigned a newline character as its
822             value.  It is read-only.  This allows expansions using the ::@@
823             modifier to put a newline between iterations of the loop rather
824             than a space.  For example, in case of an error, bbmmaakkee prints the
825             variable names and their values using:
826                   ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
827
828     _._O_B_J_D_I_R
829             A path to the directory where the targets are built.  Its value
830             is determined by trying to chdir(2) to the following directories
831             in order and using the first match:
832
833             1.   $${{MMAAKKEEOOBBJJDDIIRRPPRREEFFIIXX}}$${{..CCUURRDDIIRR}}
834
835                  (Only if `MAKEOBJDIRPREFIX' is set in the environment or on
836                  the command line.)
837
838             2.   $${{MMAAKKEEOOBBJJDDIIRR}}
839
840                  (Only if `MAKEOBJDIR' is set in the environment or on the
841                  command line.)
842
843             3.   $${{..CCUURRDDIIRR}}_/_o_b_j_.$${{MMAACCHHIINNEE}}
844
845             4.   $${{..CCUURRDDIIRR}}_/_o_b_j
846
847             5.   _/_u_s_r_/_o_b_j_/$${{..CCUURRDDIIRR}}
848
849             6.   $${{..CCUURRDDIIRR}}
850
851             Variable expansion is performed on the value before it is used,
852             so expressions such as $${{..CCUURRDDIIRR::SS,,^^//uussrr//ssrrcc,,//vvaarr//oobbjj,,}} may be
853             used.  This is especially useful with `MAKEOBJDIR'.
854
855             `_._O_B_J_D_I_R' may be modified in the makefile via the special target
856             `..OOBBJJDDIIRR'.  In all cases, bbmmaakkee changes to the specified
857             directory if it exists, and sets `_._O_B_J_D_I_R' and `_P_W_D' to that
858             directory before executing any targets.
859
860             Except in the case of an explicit `..OOBBJJDDIIRR' target, bbmmaakkee checks
861             that the specified directory is writable and ignores it if not.
862             This check can be skipped by setting the environment variable
863             `MAKE_OBJDIR_CHECK_WRITABLE' to "no".
864
865     _._P_A_R_S_E_D_I_R
866             The directory name of the current makefile being parsed.
867
868     _._P_A_R_S_E_F_I_L_E
869             The basename of the current makefile being parsed.  This variable
870             and `_._P_A_R_S_E_D_I_R' are both set only while the makefiles are being
871             parsed.  To retain their current values, assign them to a
872             variable using assignment with expansion `::=='.
873
874     _._P_A_T_H   The space-separated list of directories that bbmmaakkee searches for
875             files.  To update this search list, use the special target
876             `..PPAATTHH' rather than modifying the variable directly.
877
878     _%_P_O_S_I_X  Is set in POSIX mode, see the special `_._P_O_S_I_X' target.
879
880     _P_W_D     Alternate path to the current directory.  bbmmaakkee normally sets
881             `_._C_U_R_D_I_R' to the canonical path given by getcwd(3).  However, if
882             the environment variable `PWD' is set and gives a path to the
883             current directory, bbmmaakkee sets `_._C_U_R_D_I_R' to the value of `PWD'
884             instead.  This behavior is disabled if `MAKEOBJDIRPREFIX' is set
885             or `MAKEOBJDIR' contains a variable transform.  `_P_W_D' is set to
886             the value of `_._O_B_J_D_I_R' for all programs which bbmmaakkee executes.
887
888     _._S_H_E_L_L  The pathname of the shell used to run target scripts.  It is
889             read-only.
890
891     _._S_U_F_F_I_X_E_S
892             The list of known suffixes.  It is read-only.
893
894     _._S_Y_S_P_A_T_H
895             The space-separated list of directories that bbmmaakkee searches for
896             makefiles, referred to as the system include path.  To update
897             this search list, use the special target `..SSYYSSPPAATTHH' rather than
898             modifying the variable which is read-only.
899
900     _._T_A_R_G_E_T_S
901             The list of targets explicitly specified on the command line, if
902             any.
903
904     _V_P_A_T_H   The colon-separated (":") list of directories that bbmmaakkee searches
905             for files.  This variable is supported for compatibility with old
906             make programs only, use `_._P_A_T_H' instead.
907
908   VVaarriiaabbllee mmooddiiffiieerrss
909     The general format of a variable expansion is:
910
911           $${{_v_a_r_i_a_b_l_e[::_m_o_d_i_f_i_e_r[::...]]}}
912
913     Each modifier begins with a colon.  To escape a colon, precede it with a
914     backslash `\'.
915
916     A list of indirect modifiers can be specified via a variable, as follows:
917
918           _m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e = _m_o_d_i_f_i_e_r[::...]
919
920           $${{_v_a_r_i_a_b_l_e::$${{_m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e}}[::...]}}
921
922     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
923     with a colon, since that colon already occurs in the referencing
924     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
925     dollar sign (`$'), these must be doubled to avoid early expansion.
926
927     Some modifiers interpret the expression value as a single string, others
928     treat the expression value as a whitespace-separated list of words.  When
929     splitting a string into words, whitespace can be escaped using double
930     quotes, single quotes and backslashes, like in the shell.  The quotes and
931     backslashes are retained in the words.
932
933     The supported modifiers are:
934
935     ::EE   Replaces each word with its suffix.
936
937     ::HH   Replaces each word with its dirname.
938
939     ::MM_p_a_t_t_e_r_n
940          Selects only those words that match _p_a_t_t_e_r_n.  The standard shell
941          wildcard characters (`*', `?', and `[]') may be used.  The wildcard
942          characters may be escaped with a backslash (`\').  As a consequence
943          of the way values are split into words, matched, and then joined,
944          the construct `${VAR:M*}' removes all leading and trailing
945          whitespace and normalizes the inter-word spacing to a single space.
946
947     ::NN_p_a_t_t_e_r_n
948          This is the opposite of `::MM', selecting all words which do _n_o_t match
949          _p_a_t_t_e_r_n.
950
951     ::OO   Orders the words lexicographically.
952
953     ::OOnn  Orders the words numerically.  A number followed by one of `k', `M'
954          or `G' is multiplied by the appropriate factor, which is 1024 for
955          `k', 1048576 for `M', or 1073741824 for `G'.  Both upper- and lower-
956          case letters are accepted.
957
958     ::OOrr  Orders the words in reverse lexicographical order.
959
960     ::OOrrnn
961          Orders the words in reverse numerical order.
962
963     ::OOxx  Shuffles the words.  The results are different each time you are
964          referring to the modified variable; use the assignment with
965          expansion `::==' to prevent such behavior.  For example,
966
967                LIST=                   uno due tre quattro
968                RANDOM_LIST=            ${LIST:Ox}
969                STATIC_RANDOM_LIST:=    ${LIST:Ox}
970
971                all:
972                        @echo "${RANDOM_LIST}"
973                        @echo "${RANDOM_LIST}"
974                        @echo "${STATIC_RANDOM_LIST}"
975                        @echo "${STATIC_RANDOM_LIST}"
976          may produce output similar to:
977
978                quattro due tre uno
979                tre due quattro uno
980                due uno quattro tre
981                due uno quattro tre
982
983     ::QQ   Quotes every shell meta-character in the value, so that it can be
984          passed safely to the shell.
985
986     ::qq   Quotes every shell meta-character in the value, and also doubles `$'
987          characters so that it can be passed safely through recursive
988          invocations of bbmmaakkee.  This is equivalent to `::SS//\\$$//&&&&//gg::QQ'.
989
990     ::RR   Replaces each word with everything but its suffix.
991
992     ::rraannggee[==_c_o_u_n_t]
993          The value is an integer sequence representing the words of the
994          original value, or the supplied _c_o_u_n_t.
995
996     ::ggmmttiimmee[==_t_i_m_e_s_t_a_m_p]
997          The value is interpreted as a format string for strftime(3), using
998          gmtime(3), producing the formatted timestamp.  Note: the `%s' format
999          should only be used with `::llooccaallttiimmee'.  If a _t_i_m_e_s_t_a_m_p value is not
1000          provided or is 0, the current time is used.
1001
1002     ::hhaasshh
1003          Computes a 32-bit hash of the value and encodes it as 8 hex digits.
1004
1005     ::llooccaallttiimmee[==_t_i_m_e_s_t_a_m_p]
1006          The value is interpreted as a format string for strftime(3), using
1007          localtime(3), producing the formatted timestamp.  If a _t_i_m_e_s_t_a_m_p
1008          value is not provided or is 0, the current time is used.
1009
1010     ::mmttiimmee[==_t_i_m_e_s_t_a_m_p]
1011          Call stat(2) with each word as pathname; use `st_mtime' as the new
1012          value.  If stat(2) fails; use _t_i_m_e_s_t_a_m_p or current time.  If
1013          _t_i_m_e_s_t_a_m_p is set to `error', then stat(2) failure will cause an
1014          error.
1015
1016     ::ttAA  Attempts to convert the value to an absolute path using realpath(3).
1017          If that fails, the value is unchanged.
1018
1019     ::ttll  Converts the value to lower-case letters.
1020
1021     ::ttss_c
1022          When joining the words after a modifier that treats the value as
1023          words, the words are normally separated by a space.  This modifier
1024          changes the separator to the character _c.  If _c is omitted, no
1025          separator is used.  The common escapes (including octal numeric
1026          codes) work as expected.
1027
1028     ::tttt  Converts the first character of each word to upper-case, and the
1029          rest to lower-case letters.
1030
1031     ::ttuu  Converts the value to upper-case letters.
1032
1033     ::ttWW  Causes subsequent modifiers to treat the value as a single word
1034          (possibly containing embedded whitespace).  See also `::[[**]]'.
1035
1036     ::ttww  Causes the value to be treated as a list of words.  See also `::[[@@]]'.
1037
1038     ::SS/_o_l_d___s_t_r_i_n_g/_n_e_w___s_t_r_i_n_g/[11ggWW]
1039          Modifies the first occurrence of _o_l_d___s_t_r_i_n_g in each word of the
1040          value, replacing it with _n_e_w___s_t_r_i_n_g.  If a `g' is appended to the
1041          last delimiter of the pattern, all occurrences in each word are
1042          replaced.  If a `1' is appended to the last delimiter of the
1043          pattern, only the first occurrence is affected.  If a `W' is
1044          appended to the last delimiter of the pattern, the value is treated
1045          as a single word.  If _o_l_d___s_t_r_i_n_g begins with a caret (`^'),
1046          _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
1047          ends with a dollar sign (`$'), it is anchored at the end of each
1048          word.  Inside _n_e_w___s_t_r_i_n_g, an ampersand (`&') is replaced by
1049          _o_l_d___s_t_r_i_n_g (without the anchoring `^' or `$').  Any character may be
1050          used as the delimiter for the parts of the modifier string.  The
1051          anchoring, ampersand and delimiter characters can be escaped with a
1052          backslash (`\').
1053
1054          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
1055          prevent a dollar sign from starting a nested expression, escape it
1056          with a backslash.
1057
1058     ::CC/_p_a_t_t_e_r_n/_r_e_p_l_a_c_e_m_e_n_t/[11ggWW]
1059          The ::CC modifier works like the ::SS modifier except that the old and
1060          new strings, instead of being simple strings, are an extended
1061          regular expression _p_a_t_t_e_r_n (see regex(3)) and an ed(1)-style
1062          _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
1063          in each word of the value is substituted with _r_e_p_l_a_c_e_m_e_n_t.  The `1'
1064          modifier causes the substitution to apply to at most one word; the
1065          `g' modifier causes the substitution to apply to as many instances
1066          of the search pattern _p_a_t_t_e_r_n as occur in the word or words it is
1067          found in; the `W' modifier causes the value to be treated as a
1068          single word (possibly containing embedded whitespace).
1069
1070          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
1071          variable expansion before being parsed as regular expressions.
1072
1073     ::TT   Replaces each word with its last path component (basename).
1074
1075     ::uu   Removes adjacent duplicate words (like uniq(1)).
1076
1077     ::??_t_r_u_e___s_t_r_i_n_g::_f_a_l_s_e___s_t_r_i_n_g
1078          If the variable name (not its value), when parsed as a ..iiff
1079          conditional expression, evaluates to true, return as its value the
1080          _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
1081          name is used as the expression, :? must be the first modifier after
1082          the variable name itself--which, of course, usually contains
1083          variable expansions.  A common error is trying to use expressions
1084          like
1085                ${NUMBERS:M42:?match:no}
1086          which actually tests defined(NUMBERS).  To determine if any words
1087          match "42", you need to use something like:
1088                ${"${NUMBERS:M42}" != "":?match:no}.
1089
1090     ::_o_l_d___s_t_r_i_n_g==_n_e_w___s_t_r_i_n_g
1091          This is the AT&T System V UNIX style substitution.  It can only be
1092          the last modifier specified, as a `:' in either _o_l_d___s_t_r_i_n_g or
1093          _n_e_w___s_t_r_i_n_g is treated as a regular character, not as the end of the
1094          modifier.
1095
1096          If _o_l_d___s_t_r_i_n_g does not contain the pattern matching character `%',
1097          and the word ends with _o_l_d___s_t_r_i_n_g or equals it, that suffix is
1098          replaced with _n_e_w___s_t_r_i_n_g.
1099
1100          Otherwise, the first `%' in _o_l_d___s_t_r_i_n_g matches a possibly empty
1101          substring of arbitrary characters, and if the whole pattern is found
1102          in the word, the matching part is replaced with _n_e_w___s_t_r_i_n_g, and the
1103          first occurrence of `%' in _n_e_w___s_t_r_i_n_g (if any) is replaced with the
1104          substring matched by the `%'.
1105
1106          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
1107          prevent a dollar sign from starting a nested expression, escape it
1108          with a backslash.
1109
1110     ::@@_v_a_r_n_a_m_e@@_s_t_r_i_n_g@@
1111          This is the loop expansion mechanism from the OSF Development
1112          Environment (ODE) make.  Unlike ..ffoorr loops, expansion occurs at the
1113          time of reference.  For each word in the value, assign the word to
1114          the variable named _v_a_r_n_a_m_e and evaluate _s_t_r_i_n_g.  The ODE convention
1115          is that _v_a_r_n_a_m_e should start and end with a period, for example:
1116                ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1117
1118          However, a single-letter variable is often more readable:
1119                ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1120
1121     ::__[==_v_a_r]
1122          Saves the current variable value in `$_' or the named _v_a_r for later
1123          reference.  Example usage:
1124
1125                M_cmpv.units = 1 1000 1000000
1126                M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \
1127                \* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh
1128
1129                .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}
1130
1131          Here `$_' is used to save the result of the `:S' modifier which is
1132          later referenced using the index values from `:range'.
1133
1134     ::UU_n_e_w_v_a_l
1135          If the variable is undefined, the optional _n_e_w_v_a_l (which may be
1136          empty) is the value.  If the variable is defined, the existing value
1137          is returned.  This is another ODE make feature.  It is handy for
1138          setting per-target CFLAGS for instance:
1139                ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1140          If a value is only required if the variable is undefined, use:
1141                ${VAR:D:Unewval}
1142
1143     ::DD_n_e_w_v_a_l
1144          If the variable is defined, _n_e_w_v_a_l (which may be empty) is the
1145          value.
1146
1147     ::LL   The name of the variable is the value.
1148
1149     ::PP   The path of the node which has the same name as the variable is the
1150          value.  If no such node exists or its path is null, the name of the
1151          variable is used.  In order for this modifier to work, the name
1152          (node) must at least have appeared on the right-hand side of a
1153          dependency.
1154
1155     ::!!_c_m_d!!
1156          The output of running _c_m_d is the value.
1157
1158     ::sshh  The value is run as a command, and the output becomes the new value.
1159
1160     ::::==_s_t_r
1161          The variable is assigned the value _s_t_r after substitution.  This
1162          modifier and its variations are useful in obscure situations such as
1163          wanting to set a variable at a point where a target's shell commands
1164          are being parsed.  These assignment modifiers always expand to
1165          nothing.
1166
1167          The `::::' helps avoid false matches with the AT&T System V UNIX style
1168          `:=' modifier and since substitution always occurs, the `::=' form
1169          is vaguely appropriate.
1170
1171     ::::??==_s_t_r
1172          As for ::::== but only if the variable does not already have a value.
1173
1174     ::::++==_s_t_r
1175          Append _s_t_r to the variable.
1176
1177     ::::!!==_c_m_d
1178          Assign the output of _c_m_d to the variable.
1179
1180     ::[[_r_a_n_g_e]]
1181          Selects one or more words from the value, or performs other
1182          operations related to the way in which the value is split into
1183          words.
1184
1185          An empty value, or a value that consists entirely of white-space, is
1186          treated as a single word.  For the purposes of the `::[[]]' modifier,
1187          the words are indexed both forwards using positive integers (where
1188          index 1 represents the first word), and backwards using negative
1189          integers (where index -1 represents the last word).
1190
1191          The _r_a_n_g_e is subjected to variable expansion, and the expanded
1192          result is then interpreted as follows:
1193
1194          _i_n_d_e_x  Selects a single word from the value.
1195
1196          _s_t_a_r_t...._e_n_d
1197                 Selects all words from _s_t_a_r_t to _e_n_d, inclusive.  For example,
1198                 `::[[22....--11]]' selects all words from the second word to the last
1199                 word.  If _s_t_a_r_t is greater than _e_n_d, the words are output in
1200                 reverse order.  For example, `::[[--11....11]]' selects all the words
1201                 from last to first.  If the list is already ordered, this
1202                 effectively reverses the list, but it is more efficient to
1203                 use `::OOrr' instead of `::OO::[[--11....11]]'.
1204
1205          **      Causes subsequent modifiers to treat the value as a single
1206                 word (possibly containing embedded whitespace).  Analogous to
1207                 the effect of $* in Bourne shell.
1208
1209          0      Means the same as `::[[**]]'.
1210
1211          @@      Causes subsequent modifiers to treat the value as a sequence
1212                 of words delimited by whitespace.  Analogous to the effect of
1213                 $@ in Bourne shell.
1214
1215          ##      Returns the number of words in the value.
1216
1217DDIIRREECCTTIIVVEESS
1218     bbmmaakkee offers directives for including makefiles, conditionals and for
1219     loops.  All these directives are identified by a line beginning with a
1220     single dot (`.') character, followed by the keyword of the directive,
1221     such as iinncclluuddee or iiff.
1222
1223   FFiillee iinncclluussiioonn
1224     Files are included with either ..iinncclluuddee <<_f_i_l_e>> or ..iinncclluuddee ""_f_i_l_e"".
1225     Variables between the angle brackets or double quotes are expanded to
1226     form the file name.  If angle brackets are used, the included makefile is
1227     expected to be in the system makefile directory.  If double quotes are
1228     used, the including makefile's directory and any directories specified
1229     using the --II option are searched before the system makefile directory.
1230
1231     For compatibility with other make variants, `iinncclluuddee _f_i_l_e ...' (without
1232     leading dot) is also accepted.
1233
1234     If the include statement is written as ..--iinncclluuddee or as ..ssiinncclluuddee, errors
1235     locating and/or opening include files are ignored.
1236
1237     If the include statement is written as ..ddiinncclluuddee, not only are errors
1238     locating and/or opening include files ignored, but stale dependencies
1239     within the included file are ignored just like in _._M_A_K_E_._D_E_P_E_N_D_F_I_L_E.
1240
1241   EExxppoorrttiinngg vvaarriiaabblleess
1242     The directives for exporting and unexporting variables are:
1243
1244     ..eexxppoorrtt _v_a_r_i_a_b_l_e ...
1245             Export the specified global variable.
1246
1247             For compatibility with other make programs, eexxppoorrtt _v_a_r_i_a_b_l_e==_v_a_l_u_e
1248             (without leading dot) is also accepted.
1249
1250             Appending a variable name to _._M_A_K_E_._E_X_P_O_R_T_E_D is equivalent to
1251             exporting a variable.
1252
1253     ..eexxppoorrtt--aallll
1254             Export all globals except for internal variables (those that
1255             start with `.').  This is not affected by the --XX flag, so should
1256             be used with caution.
1257
1258     ..eexxppoorrtt--eennvv _v_a_r_i_a_b_l_e ...
1259             The same as `.export', except that the variable is not appended
1260             to _._M_A_K_E_._E_X_P_O_R_T_E_D.  This allows exporting a value to the
1261             environment which is different from that used by bbmmaakkee
1262             internally.
1263
1264     ..eexxppoorrtt--lliitteerraall _v_a_r_i_a_b_l_e ...
1265             The same as `.export-env', except that variables in the value are
1266             not expanded.
1267
1268     ..uunneexxppoorrtt _v_a_r_i_a_b_l_e ...
1269             The opposite of `.export'.  The specified global _v_a_r_i_a_b_l_e is
1270             removed from _._M_A_K_E_._E_X_P_O_R_T_E_D.  If no variable list is provided,
1271             all globals are unexported, and _._M_A_K_E_._E_X_P_O_R_T_E_D deleted.
1272
1273     ..uunneexxppoorrtt--eennvv
1274             Unexport all globals previously exported and clear the
1275             environment inherited from the parent.  This operation causes a
1276             memory leak of the original environment, so should be used
1277             sparingly.  Testing for _._M_A_K_E_._L_E_V_E_L being 0 would make sense.
1278             Also note that any variables which originated in the parent
1279             environment should be explicitly preserved if desired.  For
1280             example:
1281
1282                   .if ${.MAKE.LEVEL} == 0
1283                   PATH := ${PATH}
1284                   .unexport-env
1285                   .export PATH
1286                   .endif
1287
1288             Would result in an environment containing only `PATH', which is
1289             the minimal useful environment.  Actually `_._M_A_K_E_._L_E_V_E_L' is also
1290             pushed into the new environment.
1291
1292   MMeessssaaggeess
1293     The directives for printing messages to the output are:
1294
1295     ..iinnffoo _m_e_s_s_a_g_e
1296             The message is printed along with the name of the makefile and
1297             line number.
1298
1299     ..wwaarrnniinngg _m_e_s_s_a_g_e
1300             The message prefixed by `warning:' is printed along with the name
1301             of the makefile and line number.
1302
1303     ..eerrrroorr _m_e_s_s_a_g_e
1304             The message is printed along with the name of the makefile and
1305             line number, bbmmaakkee exits immediately.
1306
1307   CCoonnddiittiioonnaallss
1308     The directives for conditionals are:
1309
1310     ..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 ...]
1311             Test the value of an expression.
1312
1313     ..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 ...]
1314             Test whether a variable is defined.
1315
1316     ..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 ...]
1317             Test whether a variable is not defined.
1318
1319     ..iiffmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
1320             Test the target being requested.
1321
1322     ..iiffnnmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
1323             Test the target being requested.
1324
1325     ..eellssee   Reverse the sense of the last conditional.
1326
1327     ..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 ...]
1328             A combination of `..eellssee' followed by `..iiff'.
1329
1330     ..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 ...]
1331             A combination of `..eellssee' followed by `..iiffddeeff'.
1332
1333     ..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 ...]
1334             A combination of `..eellssee' followed by `..iiffnnddeeff'.
1335
1336     ..eelliiffmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
1337             A combination of `..eellssee' followed by `..iiffmmaakkee'.
1338
1339     ..eelliiffnnmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
1340             A combination of `..eellssee' followed by `..iiffnnmmaakkee'.
1341
1342     ..eennddiiff  End the body of the conditional.
1343
1344     The _o_p_e_r_a_t_o_r may be any one of the following:
1345
1346     ||||      Logical OR.
1347
1348     &&&&      Logical AND; of higher precedence than `||||'.
1349
1350     bbmmaakkee only evaluates a conditional as far as is necessary to determine
1351     its value.  Parentheses can be used to override the operator precedence.
1352     The boolean operator `!!' may be used to logically negate an expression,
1353     typically a function call.  It is of higher precedence than `&&&&'.
1354
1355     The value of _e_x_p_r_e_s_s_i_o_n may be any of the following function call
1356     expressions:
1357
1358     ddeeffiinneedd(_v_a_r_n_a_m_e)
1359             Evaluates to true if the variable _v_a_r_n_a_m_e has been defined.
1360
1361     mmaakkee(_t_a_r_g_e_t)
1362             Evaluates to true if the target was specified as part of bbmmaakkee's
1363             command line or was declared the default target (either
1364             implicitly or explicitly, see _._M_A_I_N) before the line containing
1365             the conditional.
1366
1367     eemmppttyy(_v_a_r_n_a_m_e[:_m_o_d_i_f_i_e_r_s])
1368             Evaluates to true if the expansion of the variable, after
1369             applying the modifiers, results in an empty string.
1370
1371     eexxiissttss(_p_a_t_h_n_a_m_e)
1372             Evaluates to true if the given pathname exists.  If relative, the
1373             pathname is searched for on the system search path (see _._P_A_T_H).
1374
1375     ttaarrggeett(_t_a_r_g_e_t)
1376             Evaluates to true if the target has been defined.
1377
1378     ccoommmmaannddss(_t_a_r_g_e_t)
1379             Evaluates to true if the target has been defined and has commands
1380             associated with it.
1381
1382     _E_x_p_r_e_s_s_i_o_n may also be an arithmetic or string comparison.  Variable
1383     expansion is performed on both sides of the comparison.  If both sides
1384     are numeric and neither is enclosed in quotes, the comparison is done
1385     numerically, otherwise lexicographically.  A string is interpreted as a
1386     hexadecimal integer if it is preceded by 0x, otherwise it is interpreted
1387     as a decimal floating-point number; octal numbers are not supported.
1388
1389     All comparisons may use the operators `====' and `!!=='.  Numeric comparisons
1390     may also use the operators `<<', `<<==', `>>' and `>>=='.
1391
1392     If the comparison has neither a comparison operator nor a right side, the
1393     expression evaluates to true if it is nonempty and its numeric value (if
1394     any) is not zero.
1395
1396     When bbmmaakkee is evaluating one of these conditional expressions, and it
1397     encounters a (whitespace-separated) word it doesn't recognize, either the
1398     "make" or "defined" function is applied to it, depending on the form of
1399     the conditional.  If the form is `..iiffddeeff', `..iiffnnddeeff' or `..iiff', the
1400     "defined" function is applied.  Similarly, if the form is `..iiffmmaakkee' or
1401     `..iiffnnmmaakkee', the "make" function is applied.
1402
1403     If the conditional evaluates to true, parsing of the makefile continues
1404     as before.  If it evaluates to false, the following lines until the
1405     corresponding `..eelliiff' variant, `..eellssee' or `..eennddiiff' are skipped.
1406
1407   FFoorr llooooppss
1408     For loops are typically used to apply a set of rules to a list of files.
1409     The syntax of a for loop is:
1410
1411     ..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
1412     <_m_a_k_e_-_l_i_n_e_s>
1413     ..eennddffoorr
1414
1415     The _e_x_p_r_e_s_s_i_o_n is expanded and then split into words.  On each iteration
1416     of the loop, one word is taken and assigned to each _v_a_r_i_a_b_l_e, in order,
1417     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
1418     of the for loop.  The number of words must come out even; that is, if
1419     there are three iteration variables, the number of words provided must be
1420     a multiple of three.
1421
1422     If `..bbrreeaakk' is encountered within a ..ffoorr loop, it causes early
1423     termination of the loop, otherwise a parse error.
1424
1425   OOtthheerr ddiirreeccttiivveess
1426     ..uunnddeeff _v_a_r_i_a_b_l_e ...
1427             Un-define the specified global variables.  Only global variables
1428             can be un-defined.
1429
1430CCOOMMMMEENNTTSS
1431     Comments begin with a hash (`#') character, anywhere but in a shell
1432     command line, and continue to the end of an unescaped new line.
1433
1434SSPPEECCIIAALL SSOOUURRCCEESS ((AATTTTRRIIBBUUTTEESS))
1435     ..EEXXEECC     Target is never out of date, but always execute commands
1436               anyway.
1437
1438     ..IIGGNNOORREE   Ignore any errors from the commands associated with this
1439               target, exactly as if they all were preceded by a dash (`-').
1440
1441     ..MMAADDEE     Mark all sources of this target as being up to date.
1442
1443     ..MMAAKKEE     Execute the commands associated with this target even if the --nn
1444               or --tt options were specified.  Normally used to mark recursive
1445               bbmmaakkees.
1446
1447     ..MMEETTAA     Create a meta file for the target, even if it is flagged as
1448               ..PPHHOONNYY, ..MMAAKKEE, or ..SSPPEECCIIAALL.  Usage in conjunction with ..MMAAKKEE is
1449               the most likely case.  In "meta" mode, the target is out-of-
1450               date if the meta file is missing.
1451
1452     ..NNOOMMEETTAA   Do not create a meta file for the target.  Meta files are also
1453               not created for ..PPHHOONNYY, ..MMAAKKEE, or ..SSPPEECCIIAALL targets.
1454
1455     ..NNOOMMEETTAA__CCMMPP
1456               Ignore differences in commands when deciding if target is out
1457               of date.  This is useful if the command contains a value which
1458               always changes.  If the number of commands change, though, the
1459               target is still considered out of date.  The same effect
1460               applies to any command line that uses the variable _._O_O_D_A_T_E,
1461               which can be used for that purpose even when not otherwise
1462               needed or desired:
1463
1464
1465                     skip-compare-for-some:
1466                             @echo this is compared
1467                             @echo this is not ${.OODATE:M.NOMETA_CMP}
1468                             @echo this is also compared
1469
1470               The ::MM pattern suppresses any expansion of the unwanted
1471               variable.
1472
1473     ..NNOOPPAATTHH   Do not search for the target in the directories specified by
1474               _._P_A_T_H.
1475
1476     ..NNOOTTMMAAIINN  Normally bbmmaakkee selects the first target it encounters as the
1477               default target to be built if no target was specified.  This
1478               source prevents this target from being selected.
1479
1480     ..OOPPTTIIOONNAALL
1481               If a target is marked with this attribute and bbmmaakkee can't
1482               figure out how to create it, it ignores this fact and assumes
1483               the file isn't needed or already exists.
1484
1485     ..PPHHOONNYY    The target does not correspond to an actual file; it is always
1486               considered to be out of date, and is not created with the --tt
1487               option.  Suffix-transformation rules are not applied to ..PPHHOONNYY
1488               targets.
1489
1490     ..PPRREECCIIOOUUSS
1491               When bbmmaakkee is interrupted, it normally removes any partially
1492               made targets.  This source prevents the target from being
1493               removed.
1494
1495     ..RREECCUURRSSIIVVEE
1496               Synonym for ..MMAAKKEE.
1497
1498     ..SSIILLEENNTT   Do not echo any of the commands associated with this target,
1499               exactly as if they all were preceded by an at sign (`@').
1500
1501     ..UUSSEE      Turn the target into bbmmaakkee's version of a macro.  When the
1502               target is used as a source for another target, the other target
1503               acquires the commands, sources, and attributes (except for
1504               ..UUSSEE) of the source.  If the target already has commands, the
1505               ..UUSSEE target's commands are appended to them.
1506
1507     ..UUSSEEBBEEFFOORREE
1508               Like ..UUSSEE, but instead of appending, prepend the ..UUSSEEBBEEFFOORREE
1509               target commands to the target.
1510
1511     ..WWAAIITT     If ..WWAAIITT appears in a dependency line, the sources that precede
1512               it are made before the sources that succeed it in the line.
1513               Since the dependents of files are not made until the file
1514               itself could be made, this also stops the dependents being
1515               built unless they are needed for another branch of the
1516               dependency tree.  So given:
1517
1518               x: a .WAIT b
1519                       echo x
1520               a:
1521                       echo a
1522               b: b1
1523                       echo b
1524               b1:
1525                       echo b1
1526
1527               the output is always `a', `b1', `b', `x'.
1528
1529               The ordering imposed by ..WWAAIITT is only relevant for parallel
1530               makes.
1531
1532SSPPEECCIIAALL TTAARRGGEETTSS
1533     Special targets may not be included with other targets, i.e. they must be
1534     the only target specified.
1535
1536     ..BBEEGGIINN   Any command lines attached to this target are executed before
1537              anything else is done.
1538
1539     ..DDEEFFAAUULLTT
1540              This is sort of a ..UUSSEE rule for any target (that was used only
1541              as a source) that bbmmaakkee can't figure out any other way to
1542              create.  Only the shell script is used.  The _._I_M_P_S_R_C variable of
1543              a target that inherits ..DDEEFFAAUULLTT's commands is set to the
1544              target's own name.
1545
1546     ..DDEELLEETTEE__OONN__EERRRROORR
1547              If this target is present in the makefile, it globally causes
1548              make to delete targets whose commands fail.  (By default, only
1549              targets whose commands are interrupted during execution are
1550              deleted.  This is the historical behavior.)  This setting can be
1551              used to help prevent half-finished or malformed targets from
1552              being left around and corrupting future rebuilds.
1553
1554     ..EENNDD     Any command lines attached to this target are executed after
1555              everything else is done successfully.
1556
1557     ..EERRRROORR   Any command lines attached to this target are executed when
1558              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
1559              variables that will be set.
1560
1561     ..IIGGNNOORREE  Mark each of the sources with the ..IIGGNNOORREE attribute.  If no
1562              sources are specified, this is the equivalent of specifying the
1563              --ii option.
1564
1565     ..IINNTTEERRRRUUPPTT
1566              If bbmmaakkee is interrupted, the commands for this target are
1567              executed.
1568
1569     ..MMAAIINN    If no target is specified when bbmmaakkee is invoked, this target is
1570              built.
1571
1572     ..MMAAKKEEFFLLAAGGSS
1573              This target provides a way to specify flags for bbmmaakkee at the
1574              time when the makefiles are read.  The flags are as if typed to
1575              the shell, though the --ff option has no effect.
1576
1577     ..NNOOPPAATTHH  Apply the ..NNOOPPAATTHH attribute to any specified sources.
1578
1579     ..NNOOTTPPAARRAALLLLEELL
1580              Disable parallel mode.
1581
1582     ..NNOO__PPAARRAALLLLEELL
1583              Synonym for ..NNOOTTPPAARRAALLLLEELL, for compatibility with other pmake
1584              variants.
1585
1586     ..NNOORREEAADDOONNLLYY
1587              clear the read-only attribute from the global variables
1588              specified as sources.
1589
1590     ..OOBBJJDDIIRR  The source is a new value for `_._O_B_J_D_I_R'.  If it exists, bbmmaakkee
1591              changes the current working directory to it and updates the
1592              value of `_._O_B_J_D_I_R'.
1593
1594     ..OORRDDEERR   In parallel mode, the named targets are made in sequence.  This
1595              ordering does not add targets to the list of targets to be made.
1596
1597              Since the dependents of a target do not get built until the
1598              target itself could be built, unless `a' is built by another
1599              part of the dependency graph, the following is a dependency
1600              loop:
1601
1602              .ORDER: b a
1603              b: a
1604
1605     ..PPAATTHH    The sources are directories which are to be searched for files
1606              not found in the current directory.  If no sources are
1607              specified, any previously specified directories are removed from
1608              the search path.  If the source is the special ..DDOOTTLLAASSTT target,
1609              the current working directory is searched last.
1610
1611     ..PPAATTHH.._s_u_f_f_i_x
1612              Like ..PPAATTHH but applies only to files with a particular suffix.
1613              The suffix must have been previously declared with ..SSUUFFFFIIXXEESS.
1614
1615     ..PPHHOONNYY   Apply the ..PPHHOONNYY attribute to any specified sources.
1616
1617     ..PPOOSSIIXX   If this is the first non-comment line in the main makefile, the
1618              variable _%_P_O_S_I_X is set to the value `1003.2' and the makefile
1619              `<posix.mk>' is included if it exists, to provide POSIX-
1620              compatible default rules.  If bbmmaakkee is run with the --rr flag,
1621              only `posix.mk' contributes to the default rules.
1622
1623     ..PPRREECCIIOOUUSS
1624              Apply the ..PPRREECCIIOOUUSS attribute to any specified sources.  If no
1625              sources are specified, the ..PPRREECCIIOOUUSS attribute is applied to
1626              every target in the file.
1627
1628     ..RREEAADDOONNLLYY
1629              set the read-only attribute on the global variables specified as
1630              sources.
1631
1632     ..SSHHEELLLL   Sets the shell that bbmmaakkee uses to execute commands.  The sources
1633              are a set of _f_i_e_l_d==_v_a_l_u_e pairs.
1634
1635              name        This is the minimal specification, used to select
1636                          one of the built-in shell specs; sh, ksh, and csh.
1637
1638              path        Specifies the absolute path to the shell.
1639
1640              hasErrCtl   Indicates whether the shell supports exit on error.
1641
1642              check       The command to turn on error checking.
1643
1644              ignore      The command to disable error checking.
1645
1646              echo        The command to turn on echoing of commands executed.
1647
1648              quiet       The command to turn off echoing of commands
1649                          executed.
1650
1651              filter      The output to filter after issuing the quiet
1652                          command.  It is typically identical to quiet.
1653
1654              errFlag     The flag to pass the shell to enable error checking.
1655
1656              echoFlag    The flag to pass the shell to enable command
1657                          echoing.
1658
1659              newline     The string literal to pass the shell that results in
1660                          a single newline character when used outside of any
1661                          quoting characters.
1662              Example:
1663
1664              .SHELL: name=ksh path=/bin/ksh hasErrCtl=true \
1665                      check="set -e" ignore="set +e" \
1666                      echo="set -v" quiet="set +v" filter="set +v" \
1667                      echoFlag=v errFlag=e newline="'\n'"
1668
1669     ..SSIILLEENNTT  Apply the ..SSIILLEENNTT attribute to any specified sources.  If no
1670              sources are specified, the ..SSIILLEENNTT attribute is applied to every
1671              command in the file.
1672
1673     ..SSTTAALLEE   This target gets run when a dependency file contains stale
1674              entries, having _._A_L_L_S_R_C set to the name of that dependency file.
1675
1676     ..SSUUFFFFIIXXEESS
1677              Each source specifies a suffix to bbmmaakkee.  If no sources are
1678              specified, any previously specified suffixes are deleted.  It
1679              allows the creation of suffix-transformation rules.
1680
1681              Example:
1682
1683              .SUFFIXES: .c .o
1684              .c.o:
1685                      cc -o ${.TARGET} -c ${.IMPSRC}
1686
1687     ..SSYYSSPPAATTHH
1688              The sources are directories which are to be added to the system
1689              include path which bbmmaakkee searches for makefiles.  If no sources
1690              are specified, any previously specified directories are removed
1691              from the system include path.
1692
1693EENNVVIIRROONNMMEENNTT
1694     bbmmaakkee uses the following environment variables, if they exist: MACHINE,
1695     MACHINE_ARCH, MAKE, MAKEFLAGS, MAKEOBJDIR, MAKEOBJDIRPREFIX, MAKESYSPATH,
1696     PWD, and TMPDIR.
1697
1698     MAKEOBJDIRPREFIX and MAKEOBJDIR should be set in the environment or on
1699     the command line to bbmmaakkee and not as makefile variables; see the
1700     description of `_._O_B_J_D_I_R' for more details.  It is possible to set these
1701     via makefile variables but unless done very early and the `..OOBBJJDDIIRR'
1702     target is used to reset `_._O_B_J_D_I_R', there may be unexpected side effects.
1703
1704FFIILLEESS
1705     .depend        list of dependencies
1706     makefile       first default makefile if no makefile is specified on the
1707                    command line
1708     Makefile       second default makefile if no makefile is specified on the
1709                    command line
1710     sys.mk         system makefile
1711     /usr/share/mk  system makefile directory
1712
1713CCOOMMPPAATTIIBBIILLIITTYY
1714     The basic make syntax is compatible between different make variants;
1715     however the special variables, variable modifiers and conditionals are
1716     not.
1717
1718   OOllddeerr vveerrssiioonnss
1719     An incomplete list of changes in older versions of bbmmaakkee:
1720
1721     The way that .for loop variables are substituted changed after NetBSD 5.0
1722     so that they still appear to be variable expansions.  In particular this
1723     stops them being treated as syntax, and removes some obscure problems
1724     using them in .if statements.
1725
1726     The way that parallel makes are scheduled changed in NetBSD 4.0 so that
1727     .ORDER and .WAIT apply recursively to the dependent nodes.  The
1728     algorithms used may change again in the future.
1729
1730   OOtthheerr mmaakkee ddiiaalleeccttss
1731     Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
1732     support most of the features of bbmmaakkee as described in this manual.  Most
1733     notably:
1734
1735           ++oo   The ..WWAAIITT and ..OORRDDEERR declarations and most functionality
1736               pertaining to parallelization.  (GNU make supports
1737               parallelization but lacks the features needed to control it
1738               effectively.)
1739
1740           ++oo   Directives, including for loops and conditionals and most of
1741               the forms of include files.  (GNU make has its own incompatible
1742               and less powerful syntax for conditionals.)
1743
1744           ++oo   All built-in variables that begin with a dot.
1745
1746           ++oo   Most of the special sources and targets that begin with a dot,
1747               with the notable exception of ..PPHHOONNYY, ..PPRREECCIIOOUUSS, and ..SSUUFFFFIIXXEESS.
1748
1749           ++oo   Variable modifiers, except for the `:old=new' string
1750               substitution, which does not portably support globbing with `%'
1751               and historically only works on declared suffixes.
1752
1753           ++oo   The $$>> variable even in its short form; most makes support this
1754               functionality but its name varies.
1755
1756     Some features are somewhat more portable, such as assignment with ++==, ??==,
1757     and !!==.  The _._P_A_T_H functionality is based on an older feature VVPPAATTHH found
1758     in GNU make and many versions of SVR4 make; however, historically its
1759     behavior is too ill-defined (and too buggy) to rely upon.
1760
1761     The $$@@ and $$<< variables are more or less universally portable, as is the
1762     $$((MMAAKKEE)) variable.  Basic use of suffix rules (for files only in the
1763     current directory, not trying to chain transformations together, etc.) is
1764     also reasonably portable.
1765
1766SSEEEE AALLSSOO
1767     mkdep(1)
1768
1769HHIISSTTOORRYY
1770     bbmmaakkee is derived from NetBSD make(1).  It uses autoconf to facilitate
1771     portability to other platforms.
1772
1773     A make command appeared in Version 7 AT&T UNIX.  This make implementation
1774     is based on Adam de Boor's pmake program, which was written for Sprite at
1775     Berkeley.  It was designed to be a parallel distributed make running jobs
1776     on different machines using a daemon called "customs".
1777
1778     Historically the target/dependency FFRRCC has been used to FoRCe rebuilding
1779     (since the target/dependency does not exist ... unless someone creates an
1780     _F_R_C file).
1781
1782BBUUGGSS
1783     The bbmmaakkee syntax is difficult to parse.  For instance, finding the end of
1784     a variable's use should involve scanning each of the modifiers, using the
1785     correct terminator for each field.  In many places bbmmaakkee just counts {}
1786     and () in order to find the end of a variable expansion.
1787
1788     There is no way of escaping a space character in a filename.
1789
1790     In jobs mode, when a target fails; bbmmaakkee will put an error token into the
1791     job token pool.  This will cause all other instances of bbmmaakkee using that
1792     token pool to abort the build and exit with error code 6.  Sometimes the
1793     attempt to suppress a cascade of unnecessary errors, can result in a
1794     seemingly unexplained `*** Error code 6'
1795
1796FreeBSD 14.1-RELEASE-p5        November 14, 2024       FreeBSD 14.1-RELEASE-p5
1797