xref: /freebsd/contrib/bmake/bmake.1 (revision 9fe48b8076ae9c6dc486d713c468ff03ec056eda)
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29.\"
30.\"	from: @(#)make.1	8.4 (Berkeley) 3/19/94
31.\"
32.Dd April 9, 2015
33.Dt MAKE 1
34.Os
35.Sh NAME
36.Nm bmake
37.Nd maintain program dependencies
38.Sh SYNOPSIS
39.Nm
40.Op Fl BeikNnqrstWwX
41.Op Fl C Ar directory
42.Op Fl D Ar variable
43.Op Fl d Ar flags
44.Op Fl f Ar makefile
45.Op Fl I Ar directory
46.Op Fl J Ar private
47.Op Fl j Ar max_jobs
48.Op Fl m Ar directory
49.Op Fl T Ar file
50.Op Fl V Ar variable
51.Op Ar variable=value
52.Op Ar target ...
53.Sh DESCRIPTION
54.Nm
55is a program designed to simplify the maintenance of other programs.
56Its input is a list of specifications as to the files upon which programs
57and other files depend.
58If no
59.Fl f Ar makefile
60makefile option is given,
61.Nm
62will try to open
63.Ql Pa makefile
64then
65.Ql Pa Makefile
66in order to find the specifications.
67If the file
68.Ql Pa .depend
69exists, it is read (see
70.Xr mkdep 1 ) .
71.Pp
72This manual page is intended as a reference document only.
73For a more thorough description of
74.Nm
75and makefiles, please refer to
76.%T "PMake \- A Tutorial" .
77.Pp
78.Nm
79will prepend the contents of the
80.Va MAKEFLAGS
81environment variable to the command line arguments before parsing them.
82.Pp
83The options are as follows:
84.Bl -tag -width Ds
85.It Fl B
86Try to be backwards compatible by executing a single shell per command and
87by executing the commands to make the sources of a dependency line in sequence.
88.It Fl C Ar directory
89Change to
90.Ar directory
91before reading the makefiles or doing anything else.
92If multiple
93.Fl C
94options are specified, each is interpreted relative to the previous one:
95.Fl C Pa / Fl C Pa etc
96is equivalent to
97.Fl C Pa /etc .
98.It Fl D Ar variable
99Define
100.Ar variable
101to be 1, in the global context.
102.It Fl d Ar [-]flags
103Turn on debugging, and specify which portions of
104.Nm
105are to print debugging information.
106Unless the flags are preceded by
107.Ql \-
108they are added to the
109.Va MAKEFLAGS
110environment variable and will be processed by any child make processes.
111By default, debugging information is printed to standard error,
112but this can be changed using the
113.Ar F
114debugging flag.
115The debugging output is always unbuffered; in addition, if debugging
116is enabled but debugging output is not directed to standard output,
117then the standard output is line buffered.
118.Ar Flags
119is one or more of the following:
120.Bl -tag -width Ds
121.It Ar A
122Print all possible debugging information;
123equivalent to specifying all of the debugging flags.
124.It Ar a
125Print debugging information about archive searching and caching.
126.It Ar C
127Print debugging information about current working directory.
128.It Ar c
129Print debugging information about conditional evaluation.
130.It Ar d
131Print debugging information about directory searching and caching.
132.It Ar e
133Print debugging information about failed commands and targets.
134.It Ar F Ns Oo Sy \&+ Oc Ns Ar filename
135Specify where debugging output is written.
136This must be the last flag, because it consumes the remainder of
137the argument.
138If the character immediately after the
139.Ql F
140flag is
141.Ql \&+ ,
142then the file will be opened in append mode;
143otherwise the file will be overwritten.
144If the file name is
145.Ql stdout
146or
147.Ql stderr
148then debugging output will be written to the
149standard output or standard error output file descriptors respectively
150(and the
151.Ql \&+
152option has no effect).
153Otherwise, the output will be written to the named file.
154If the file name ends
155.Ql .%d
156then the
157.Ql %d
158is replaced by the pid.
159.It Ar f
160Print debugging information about loop evaluation.
161.It Ar "g1"
162Print the input graph before making anything.
163.It Ar "g2"
164Print the input graph after making everything, or before exiting
165on error.
166.It Ar "g3"
167Print the input graph before exiting on error.
168.It Ar j
169Print debugging information about running multiple shells.
170.It Ar l
171Print commands in Makefiles regardless of whether or not they are prefixed by
172.Ql @
173or other "quiet" flags.
174Also known as "loud" behavior.
175.It Ar M
176Print debugging information about "meta" mode decisions about targets.
177.It Ar m
178Print debugging information about making targets, including modification
179dates.
180.It Ar n
181Don't delete the temporary command scripts created when running commands.
182These temporary scripts are created in the directory
183referred to by the
184.Ev TMPDIR
185environment variable, or in
186.Pa /tmp
187if
188.Ev TMPDIR
189is unset or set to the empty string.
190The temporary scripts are created by
191.Xr mkstemp 3 ,
192and have names of the form
193.Pa makeXXXXXX .
194.Em NOTE :
195This can create many files in
196.Ev TMPDIR
197or
198.Pa /tmp ,
199so use with care.
200.It Ar p
201Print debugging information about makefile parsing.
202.It Ar s
203Print debugging information about suffix-transformation rules.
204.It Ar t
205Print debugging information about target list maintenance.
206.It Ar V
207Force the
208.Fl V
209option to print raw values of variables.
210.It Ar v
211Print debugging information about variable assignment.
212.It Ar x
213Run shell commands with
214.Fl x
215so the actual commands are printed as they are executed.
216.El
217.It Fl e
218Specify that environment variables override macro assignments within
219makefiles.
220.It Fl f Ar makefile
221Specify a makefile to read instead of the default
222.Ql Pa makefile .
223If
224.Ar makefile
225is
226.Ql Fl ,
227standard input is read.
228Multiple makefiles may be specified, and are read in the order specified.
229.It Fl I Ar directory
230Specify a directory in which to search for makefiles and included makefiles.
231The system makefile directory (or directories, see the
232.Fl m
233option) is automatically included as part of this list.
234.It Fl i
235Ignore non-zero exit of shell commands in the makefile.
236Equivalent to specifying
237.Ql Fl
238before each command line in the makefile.
239.It Fl J Ar private
240This option should
241.Em not
242be specified by the user.
243.Pp
244When the
245.Ar j
246option is in use in a recursive build, this option is passed by a make
247to child makes to allow all the make processes in the build to
248cooperate to avoid overloading the system.
249.It Fl j Ar max_jobs
250Specify the maximum number of jobs that
251.Nm
252may have running at any one time.
253The value is saved in
254.Va .MAKE.JOBS .
255Turns compatibility mode off, unless the
256.Ar B
257flag is also specified.
258When compatibility mode is off, all commands associated with a
259target are executed in a single shell invocation as opposed to the
260traditional one shell invocation per line.
261This can break traditional scripts which change directories on each
262command invocation and then expect to start with a fresh environment
263on the next line.
264It is more efficient to correct the scripts rather than turn backwards
265compatibility on.
266.It Fl k
267Continue processing after errors are encountered, but only on those targets
268that do not depend on the target whose creation caused the error.
269.It Fl m Ar directory
270Specify a directory in which to search for sys.mk and makefiles included
271via the
272.Ao Ar file Ac Ns -style
273include statement.
274The
275.Fl m
276option can be used multiple times to form a search path.
277This path will override the default system include path: /usr/share/mk.
278Furthermore the system include path will be appended to the search path used
279for
280.Qo Ar file Qc Ns -style
281include statements (see the
282.Fl I
283option).
284.Pp
285If a file or directory name in the
286.Fl m
287argument (or the
288.Ev MAKESYSPATH
289environment variable) starts with the string
290.Qq \&.../
291then
292.Nm
293will search for the specified file or directory named in the remaining part
294of the argument string.
295The search starts with the current directory of
296the Makefile and then works upward towards the root of the filesystem.
297If the search is successful, then the resulting directory replaces the
298.Qq \&.../
299specification in the
300.Fl m
301argument.
302If used, this feature allows
303.Nm
304to easily search in the current source tree for customized sys.mk files
305(e.g., by using
306.Qq \&.../mk/sys.mk
307as an argument).
308.It Fl n
309Display the commands that would have been executed, but do not
310actually execute them unless the target depends on the .MAKE special
311source (see below).
312.It Fl N
313Display the commands which would have been executed, but do not
314actually execute any of them; useful for debugging top-level makefiles
315without descending into subdirectories.
316.It Fl q
317Do not execute any commands, but exit 0 if the specified targets are
318up-to-date and 1, otherwise.
319.It Fl r
320Do not use the built-in rules specified in the system makefile.
321.It Fl s
322Do not echo any commands as they are executed.
323Equivalent to specifying
324.Ql Ic @
325before each command line in the makefile.
326.It Fl T Ar tracefile
327When used with the
328.Fl j
329flag,
330append a trace record to
331.Ar tracefile
332for each job started and completed.
333.It Fl t
334Rather than re-building a target as specified in the makefile, create it
335or update its modification time to make it appear up-to-date.
336.It Fl V Ar variable
337Print
338.Nm Ns 's
339idea of the value of
340.Ar variable ,
341in the global context.
342Do not build any targets.
343Multiple instances of this option may be specified;
344the variables will be printed one per line,
345with a blank line for each null or undefined variable.
346If
347.Ar variable
348contains a
349.Ql \&$
350then the value will be expanded before printing.
351.It Fl W
352Treat any warnings during makefile parsing as errors.
353.It Fl w
354Print entering and leaving directory messages, pre and post processing.
355.It Fl X
356Don't export variables passed on the command line to the environment
357individually.
358Variables passed on the command line are still exported
359via the
360.Va MAKEFLAGS
361environment variable.
362This option may be useful on systems which have a small limit on the
363size of command arguments.
364.It Ar variable=value
365Set the value of the variable
366.Ar variable
367to
368.Ar value .
369Normally, all values passed on the command line are also exported to
370sub-makes in the environment.
371The
372.Fl X
373flag disables this behavior.
374Variable assignments should follow options for POSIX compatibility
375but no ordering is enforced.
376.El
377.Pp
378There are seven different types of lines in a makefile: file dependency
379specifications, shell commands, variable assignments, include statements,
380conditional directives, for loops, and comments.
381.Pp
382In general, lines may be continued from one line to the next by ending
383them with a backslash
384.Pq Ql \e .
385The trailing newline character and initial whitespace on the following
386line are compressed into a single space.
387.Sh FILE DEPENDENCY SPECIFICATIONS
388Dependency lines consist of one or more targets, an operator, and zero
389or more sources.
390This creates a relationship where the targets
391.Dq depend
392on the sources
393and are usually created from them.
394The exact relationship between the target and the source is determined
395by the operator that separates them.
396The three operators are as follows:
397.Bl -tag -width flag
398.It Ic \&:
399A target is considered out-of-date if its modification time is less than
400those of any of its sources.
401Sources for a target accumulate over dependency lines when this operator
402is used.
403The target is removed if
404.Nm
405is interrupted.
406.It Ic \&!
407Targets are always re-created, but not until all sources have been
408examined and re-created as necessary.
409Sources for a target accumulate over dependency lines when this operator
410is used.
411The target is removed if
412.Nm
413is interrupted.
414.It Ic \&::
415If no sources are specified, the target is always re-created.
416Otherwise, a target is considered out-of-date if any of its sources has
417been modified more recently than the target.
418Sources for a target do not accumulate over dependency lines when this
419operator is used.
420The target will not be removed if
421.Nm
422is interrupted.
423.El
424.Pp
425Targets and sources may contain the shell wildcard values
426.Ql \&? ,
427.Ql * ,
428.Ql [] ,
429and
430.Ql {} .
431The values
432.Ql \&? ,
433.Ql * ,
434and
435.Ql []
436may only be used as part of the final
437component of the target or source, and must be used to describe existing
438files.
439The value
440.Ql {}
441need not necessarily be used to describe existing files.
442Expansion is in directory order, not alphabetically as done in the shell.
443.Sh SHELL COMMANDS
444Each target may have associated with it one or more lines of shell
445commands, normally
446used to create the target.
447Each of the lines in this script
448.Em must
449be preceded by a tab.
450(For historical reasons, spaces are not accepted.)
451While targets can appear in many dependency lines if desired, by
452default only one of these rules may be followed by a creation
453script.
454If the
455.Ql Ic \&::
456operator is used, however, all rules may include scripts and the
457scripts are executed in the order found.
458.Pp
459Each line is treated as a separate shell command, unless the end of
460line is escaped with a backslash
461.Pq Ql \e
462in which case that line and the next are combined.
463.\" The escaped newline is retained and passed to the shell, which
464.\" normally ignores it.
465.\" However, the tab at the beginning of the following line is removed.
466If the first characters of the command are any combination of
467.Ql Ic @ ,
468.Ql Ic + ,
469or
470.Ql Ic \- ,
471the command is treated specially.
472A
473.Ql Ic @
474causes the command not to be echoed before it is executed.
475A
476.Ql Ic +
477causes the command to be executed even when
478.Fl n
479is given.
480This is similar to the effect of the .MAKE special source,
481except that the effect can be limited to a single line of a script.
482A
483.Ql Ic \-
484in compatibility mode
485causes any non-zero exit status of the command line to be ignored.
486.Pp
487When
488.Nm
489is run in jobs mode with
490.Fl j Ar max_jobs ,
491the entire script for the target is fed to a
492single instance of the shell.
493In compatibility (non-jobs) mode, each command is run in a separate process.
494If the command contains any shell meta characters
495.Pq Ql #=|^(){};&<>*?[]:$`\e\en
496it will be passed to the shell; otherwise
497.Nm
498will attempt direct execution.
499If a line starts with
500.Ql Ic \-
501and the shell has ErrCtl enabled then failure of the command line
502will be ignored as in compatibility mode.
503Otherwise
504.Ql Ic \-
505affects the entire job;
506the script will stop at the first command line that fails,
507but the target will not be deemed to have failed.
508.Pp
509Makefiles should be written so that the mode of
510.Nm
511operation does not change their behavior.
512For example, any command which needs to use
513.Dq cd
514or
515.Dq chdir
516without potentially changing the directory for subsequent commands
517should be put in parentheses so it executes in a subshell.
518To force the use of one shell, escape the line breaks so as to make
519the whole script one command.
520For example:
521.Bd -literal -offset indent
522avoid-chdir-side-effects:
523	@echo Building $@ in `pwd`
524	@(cd ${.CURDIR} && ${MAKE} $@)
525	@echo Back in `pwd`
526
527ensure-one-shell-regardless-of-mode:
528	@echo Building $@ in `pwd`; \e
529	(cd ${.CURDIR} && ${MAKE} $@); \e
530	echo Back in `pwd`
531.Ed
532.Pp
533Since
534.Nm
535will
536.Xr chdir 2
537to
538.Ql Va .OBJDIR
539before executing any targets, each child process
540starts with that as its current working directory.
541.Sh VARIABLE ASSIGNMENTS
542Variables in make are much like variables in the shell, and, by tradition,
543consist of all upper-case letters.
544.Ss Variable assignment modifiers
545The five operators that can be used to assign values to variables are as
546follows:
547.Bl -tag -width Ds
548.It Ic \&=
549Assign the value to the variable.
550Any previous value is overridden.
551.It Ic \&+=
552Append the value to the current value of the variable.
553.It Ic \&?=
554Assign the value to the variable if it is not already defined.
555.It Ic \&:=
556Assign with expansion, i.e. expand the value before assigning it
557to the variable.
558Normally, expansion is not done until the variable is referenced.
559.Em NOTE :
560References to undefined variables are
561.Em not
562expanded.
563This can cause problems when variable modifiers are used.
564.It Ic \&!=
565Expand the value and pass it to the shell for execution and assign
566the result to the variable.
567Any newlines in the result are replaced with spaces.
568.El
569.Pp
570Any white-space before the assigned
571.Ar value
572is removed; if the value is being appended, a single space is inserted
573between the previous contents of the variable and the appended value.
574.Pp
575Variables are expanded by surrounding the variable name with either
576curly braces
577.Pq Ql {}
578or parentheses
579.Pq Ql ()
580and preceding it with
581a dollar sign
582.Pq Ql \&$ .
583If the variable name contains only a single letter, the surrounding
584braces or parentheses are not required.
585This shorter form is not recommended.
586.Pp
587If the variable name contains a dollar, then the name itself is expanded first.
588This allows almost arbitrary variable names, however names containing dollar,
589braces, parenthesis, or whitespace are really best avoided!
590.Pp
591If the result of expanding a variable contains a dollar sign
592.Pq Ql \&$
593the string is expanded again.
594.Pp
595Variable substitution occurs at three distinct times, depending on where
596the variable is being used.
597.Bl -enum
598.It
599Variables in dependency lines are expanded as the line is read.
600.It
601Variables in shell commands are expanded when the shell command is
602executed.
603.It
604.Dq .for
605loop index variables are expanded on each loop iteration.
606Note that other variables are not expanded inside loops so
607the following example code:
608.Bd -literal -offset indent
609
610.Dv .for i in 1 2 3
611a+=     ${i}
612j=      ${i}
613b+=     ${j}
614.Dv .endfor
615
616all:
617	@echo ${a}
618	@echo ${b}
619
620.Ed
621will print:
622.Bd -literal -offset indent
6231 2 3
6243 3 3
625
626.Ed
627Because while ${a} contains
628.Dq 1 2 3
629after the loop is executed, ${b}
630contains
631.Dq ${j} ${j} ${j}
632which expands to
633.Dq 3 3 3
634since after the loop completes ${j} contains
635.Dq 3 .
636.El
637.Ss Variable classes
638The four different classes of variables (in order of increasing precedence)
639are:
640.Bl -tag -width Ds
641.It Environment variables
642Variables defined as part of
643.Nm Ns 's
644environment.
645.It Global variables
646Variables defined in the makefile or in included makefiles.
647.It Command line variables
648Variables defined as part of the command line.
649.It Local variables
650Variables that are defined specific to a certain target.
651.El
652.Pp
653Local variables are all built in and their values vary magically from
654target to target.
655It is not currently possible to define new local variables.
656The seven local variables are as follows:
657.Bl -tag -width ".ARCHIVE" -offset indent
658.It Va .ALLSRC
659The list of all sources for this target; also known as
660.Ql Va \&\*[Gt] .
661.It Va .ARCHIVE
662The name of the archive file; also known as
663.Ql Va \&! .
664.It Va .IMPSRC
665In suffix-transformation rules, the name/path of the source from which the
666target is to be transformed (the
667.Dq implied
668source); also known as
669.Ql Va \&\*[Lt] .
670It is not defined in explicit rules.
671.It Va .MEMBER
672The name of the archive member; also known as
673.Ql Va % .
674.It Va .OODATE
675The list of sources for this target that were deemed out-of-date; also
676known as
677.Ql Va \&? .
678.It Va .PREFIX
679The file prefix of the target, containing only the file portion, no suffix
680or preceding directory components; also known as
681.Ql Va * .
682The suffix must be one of the known suffixes declared with
683.Ic .SUFFIXES
684or it will not be recognized.
685.It Va .TARGET
686The name of the target; also known as
687.Ql Va @ .
688.El
689.Pp
690The shorter forms
691.Ql ( Va \*[Gt] ,
692.Ql Va \&! ,
693.Ql Va \*[Lt] ,
694.Ql Va % ,
695.Ql Va \&? ,
696.Ql Va * ,
697and
698.Ql Va @ )
699are permitted for backward
700compatibility with historical makefiles and legacy POSIX make and are
701not recommended.
702.Pp
703Variants of these variables with the punctuation followed immediately by
704.Ql D
705or
706.Ql F ,
707e.g.
708.Ql Va $(@D) ,
709are legacy forms equivalent to using the
710.Ql :H
711and
712.Ql :T
713modifiers.
714These forms are accepted for compatibility with
715.At V
716makefiles and POSIX but are not recommended.
717.Pp
718Four of the local variables may be used in sources on dependency lines
719because they expand to the proper value for each target on the line.
720These variables are
721.Ql Va .TARGET ,
722.Ql Va .PREFIX ,
723.Ql Va .ARCHIVE ,
724and
725.Ql Va .MEMBER .
726.Ss Additional built-in variables
727In addition,
728.Nm
729sets or knows about the following variables:
730.Bl -tag -width .MAKEOVERRIDES
731.It Va \&$
732A single dollar sign
733.Ql \&$ ,
734i.e.
735.Ql \&$$
736expands to a single dollar
737sign.
738.It Va .ALLTARGETS
739The list of all targets encountered in the Makefile.
740If evaluated during
741Makefile parsing, lists only those targets encountered thus far.
742.It Va .CURDIR
743A path to the directory where
744.Nm
745was executed.
746Refer to the description of
747.Ql Ev PWD
748for more details.
749.It Va .INCLUDEDFROMDIR
750The directory of the file this Makefile was included from.
751.It Va .INCLUDEDFROMFILE
752The filename of the file this Makefile was included from.
753.It Ev MAKE
754The name that
755.Nm
756was executed with
757.Pq Va argv[0] .
758For compatibility
759.Nm
760also sets
761.Va .MAKE
762with the same value.
763The preferred variable to use is the environment variable
764.Ev MAKE
765because it is more compatible with other versions of
766.Nm
767and cannot be confused with the special target with the same name.
768.It Va .MAKE.DEPENDFILE
769Names the makefile (default
770.Ql Pa .depend )
771from which generated dependencies are read.
772.It Va .MAKE.EXPAND_VARIABLES
773A boolean that controls the default behavior of the
774.Fl V
775option.
776.It Va .MAKE.EXPORTED
777The list of variables exported by
778.Nm .
779.It Va .MAKE.JOBS
780The argument to the
781.Fl j
782option.
783.It Va .MAKE.JOB.PREFIX
784If
785.Nm
786is run with
787.Ar j
788then output for each target is prefixed with a token
789.Ql --- target ---
790the first part of which can be controlled via
791.Va .MAKE.JOB.PREFIX .
792If
793.Va .MAKE.JOB.PREFIX
794is empty, no token is printed.
795.br
796For example:
797.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
798would produce tokens like
799.Ql ---make[1234] target ---
800making it easier to track the degree of parallelism being achieved.
801.It Ev MAKEFLAGS
802The environment variable
803.Ql Ev MAKEFLAGS
804may contain anything that
805may be specified on
806.Nm Ns 's
807command line.
808Anything specified on
809.Nm Ns 's
810command line is appended to the
811.Ql Ev MAKEFLAGS
812variable which is then
813entered into the environment for all programs which
814.Nm
815executes.
816.It Va .MAKE.LEVEL
817The recursion depth of
818.Nm .
819The initial instance of
820.Nm
821will be 0, and an incremented value is put into the environment
822to be seen by the next generation.
823This allows tests like:
824.Li .if ${.MAKE.LEVEL} == 0
825to protect things which should only be evaluated in the initial instance of
826.Nm .
827.It Va .MAKE.MAKEFILE_PREFERENCE
828The ordered list of makefile names
829(default
830.Ql Pa makefile ,
831.Ql Pa Makefile )
832that
833.Nm
834will look for.
835.It Va .MAKE.MAKEFILES
836The list of makefiles read by
837.Nm ,
838which is useful for tracking dependencies.
839Each makefile is recorded only once, regardless of the number of times read.
840.It Va .MAKE.MODE
841Processed after reading all makefiles.
842Can affect the mode that
843.Nm
844runs in.
845It can contain a number of keywords:
846.Bl -hang -width ignore-cmd
847.It Pa compat
848Like
849.Fl B ,
850puts
851.Nm
852into "compat" mode.
853.It Pa meta
854Puts
855.Nm
856into "meta" mode, where meta files are created for each target
857to capture the command run, the output generated and if
858.Xr filemon 4
859is available, the system calls which are of interest to
860.Nm .
861The captured output can be very useful when diagnosing errors.
862.It Pa curdirOk= Ar bf
863Normally
864.Nm
865will not create .meta files in
866.Ql Va .CURDIR .
867This can be overridden by setting
868.Va bf
869to a value which represents True.
870.It Pa env
871For debugging, it can be useful to inlcude the environment
872in the .meta file.
873.It Pa verbose
874If in "meta" mode, print a clue about the target being built.
875This is useful if the build is otherwise running silently.
876The message printed the value of:
877.Va .MAKE.META.PREFIX .
878.It Pa ignore-cmd
879Some makefiles have commands which are simply not stable.
880This keyword causes them to be ignored for
881determining whether a target is out of date in "meta" mode.
882See also
883.Ic .NOMETA_CMP .
884.It Pa silent= Ar bf
885If
886.Va bf
887is True, when a .meta file is created, mark the target
888.Ic .SILENT .
889.El
890.It Va .MAKE.META.BAILIWICK
891In "meta" mode, provides a list of prefixes which
892match the directories controlled by
893.Nm .
894If a file that was generated outside of
895.Va .OBJDIR
896but within said bailiwick is missing,
897the current target is considered out-of-date.
898.It Va .MAKE.META.CREATED
899In "meta" mode, this variable contains a list of all the meta files
900updated.
901If not empty, it can be used to trigger processing of
902.Va .MAKE.META.FILES .
903.It Va .MAKE.META.FILES
904In "meta" mode, this variable contains a list of all the meta files
905used (updated or not).
906This list can be used to process the meta files to extract dependency
907information.
908.It Va .MAKE.META.IGNORE_PATHS
909Provides a list of path prefixes that should be ignored;
910because the contents are expected to change over time.
911The default list includes:
912.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
913.It Va .MAKE.META.PREFIX
914Defines the message printed for each meta file updated in "meta verbose" mode.
915The default value is:
916.Dl Building ${.TARGET:H:tA}/${.TARGET:T}
917.It Va .MAKEOVERRIDES
918This variable is used to record the names of variables assigned to
919on the command line, so that they may be exported as part of
920.Ql Ev MAKEFLAGS .
921This behaviour can be disabled by assigning an empty value to
922.Ql Va .MAKEOVERRIDES
923within a makefile.
924Extra variables can be exported from a makefile
925by appending their names to
926.Ql Va .MAKEOVERRIDES .
927.Ql Ev MAKEFLAGS
928is re-exported whenever
929.Ql Va .MAKEOVERRIDES
930is modified.
931.It Va .MAKE.PATH_FILEMON
932If
933.Nm
934was built with
935.Xr filemon 4
936support, this is set to the path of the device node.
937This allows makefiles to test for this support.
938.It Va .MAKE.PID
939The process-id of
940.Nm .
941.It Va .MAKE.PPID
942The parent process-id of
943.Nm .
944.It Va MAKE_PRINT_VAR_ON_ERROR
945When
946.Nm
947stops due to an error, it prints its name and the value of
948.Ql Va .CURDIR
949as well as the value of any variables named in
950.Ql Va MAKE_PRINT_VAR_ON_ERROR .
951.It Va .newline
952This variable is simply assigned a newline character as its value.
953This allows expansions using the
954.Cm \&:@
955modifier to put a newline between
956iterations of the loop rather than a space.
957For example, the printing of
958.Ql Va MAKE_PRINT_VAR_ON_ERROR
959could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
960.It Va .OBJDIR
961A path to the directory where the targets are built.
962Its value is determined by trying to
963.Xr chdir 2
964to the following directories in order and using the first match:
965.Bl -enum
966.It
967.Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
968.Pp
969(Only if
970.Ql Ev MAKEOBJDIRPREFIX
971is set in the environment or on the command line.)
972.It
973.Ev ${MAKEOBJDIR}
974.Pp
975(Only if
976.Ql Ev MAKEOBJDIR
977is set in the environment or on the command line.)
978.It
979.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
980.It
981.Ev ${.CURDIR} Ns Pa /obj
982.It
983.Pa /usr/obj/ Ns Ev ${.CURDIR}
984.It
985.Ev ${.CURDIR}
986.El
987.Pp
988Variable expansion is performed on the value before it's used,
989so expressions such as
990.Dl ${.CURDIR:S,^/usr/src,/var/obj,}
991may be used.
992This is especially useful with
993.Ql Ev MAKEOBJDIR .
994.Pp
995.Ql Va .OBJDIR
996may be modified in the makefile as a global variable.
997In all cases,
998.Nm
999will
1000.Xr chdir 2
1001to
1002.Ql Va .OBJDIR
1003and set
1004.Ql Ev PWD
1005to that directory before executing any targets.
1006.
1007.It Va .PARSEDIR
1008A path to the directory of the current
1009.Ql Pa Makefile
1010being parsed.
1011.It Va .PARSEFILE
1012The basename of the current
1013.Ql Pa Makefile
1014being parsed.
1015This variable and
1016.Ql Va .PARSEDIR
1017are both set only while the
1018.Ql Pa Makefiles
1019are being parsed.
1020If you want to retain their current values, assign them to a variable
1021using assignment with expansion:
1022.Pq Ql Cm \&:= .
1023.It Va .PATH
1024A variable that represents the list of directories that
1025.Nm
1026will search for files.
1027The search list should be updated using the target
1028.Ql Va .PATH
1029rather than the variable.
1030.It Ev PWD
1031Alternate path to the current directory.
1032.Nm
1033normally sets
1034.Ql Va .CURDIR
1035to the canonical path given by
1036.Xr getcwd 3 .
1037However, if the environment variable
1038.Ql Ev PWD
1039is set and gives a path to the current directory, then
1040.Nm
1041sets
1042.Ql Va .CURDIR
1043to the value of
1044.Ql Ev PWD
1045instead.
1046This behaviour is disabled if
1047.Ql Ev MAKEOBJDIRPREFIX
1048is set or
1049.Ql Ev MAKEOBJDIR
1050contains a variable transform.
1051.Ql Ev PWD
1052is set to the value of
1053.Ql Va .OBJDIR
1054for all programs which
1055.Nm
1056executes.
1057.It Ev .TARGETS
1058The list of targets explicitly specified on the command line, if any.
1059.It Ev VPATH
1060Colon-separated
1061.Pq Dq \&:
1062lists of directories that
1063.Nm
1064will search for files.
1065The variable is supported for compatibility with old make programs only,
1066use
1067.Ql Va .PATH
1068instead.
1069.El
1070.Ss Variable modifiers
1071Variable expansion may be modified to select or modify each word of the
1072variable (where a
1073.Dq word
1074is white-space delimited sequence of characters).
1075The general format of a variable expansion is as follows:
1076.Pp
1077.Dl ${variable[:modifier[:...]]}
1078.Pp
1079Each modifier begins with a colon,
1080which may be escaped with a backslash
1081.Pq Ql \e .
1082.Pp
1083A set of modifiers can be specified via a variable, as follows:
1084.Pp
1085.Dl modifier_variable=modifier[:...]
1086.Dl ${variable:${modifier_variable}[:...]}
1087.Pp
1088In this case the first modifier in the modifier_variable does not
1089start with a colon, since that must appear in the referencing
1090variable.
1091If any of the modifiers in the modifier_variable contain a dollar sign
1092.Pq Ql $ ,
1093these must be doubled to avoid early expansion.
1094.Pp
1095The supported modifiers are:
1096.Bl -tag -width EEE
1097.It Cm \&:E
1098Replaces each word in the variable with its suffix.
1099.It Cm \&:H
1100Replaces each word in the variable with everything but the last component.
1101.It Cm \&:M Ns Ar pattern
1102Select only those words that match
1103.Ar pattern .
1104The standard shell wildcard characters
1105.Pf ( Ql * ,
1106.Ql \&? ,
1107and
1108.Ql Oo Oc )
1109may
1110be used.
1111The wildcard characters may be escaped with a backslash
1112.Pq Ql \e .
1113As a consequence of the way values are split into words, matched,
1114and then joined, a construct like
1115.Dl ${VAR:M*}
1116will normalise the inter-word spacing, removing all leading and
1117trailing space, and converting multiple consecutive spaces
1118to single spaces.
1119.
1120.It Cm \&:N Ns Ar pattern
1121This is identical to
1122.Ql Cm \&:M ,
1123but selects all words which do not match
1124.Ar pattern .
1125.It Cm \&:O
1126Order every word in variable alphabetically.
1127To sort words in
1128reverse order use the
1129.Ql Cm \&:O:[-1..1]
1130combination of modifiers.
1131.It Cm \&:Ox
1132Randomize words in variable.
1133The results will be different each time you are referring to the
1134modified variable; use the assignment with expansion
1135.Pq Ql Cm \&:=
1136to prevent such behaviour.
1137For example,
1138.Bd -literal -offset indent
1139LIST=			uno due tre quattro
1140RANDOM_LIST=		${LIST:Ox}
1141STATIC_RANDOM_LIST:=	${LIST:Ox}
1142
1143all:
1144	@echo "${RANDOM_LIST}"
1145	@echo "${RANDOM_LIST}"
1146	@echo "${STATIC_RANDOM_LIST}"
1147	@echo "${STATIC_RANDOM_LIST}"
1148.Ed
1149may produce output similar to:
1150.Bd -literal -offset indent
1151quattro due tre uno
1152tre due quattro uno
1153due uno quattro tre
1154due uno quattro tre
1155.Ed
1156.It Cm \&:Q
1157Quotes every shell meta-character in the variable, so that it can be passed
1158safely through recursive invocations of
1159.Nm .
1160.It Cm \&:R
1161Replaces each word in the variable with everything but its suffix.
1162.It Cm \&:gmtime
1163The value is a format string for
1164.Xr strftime 3 ,
1165using the current
1166.Xr gmtime 3 .
1167.It Cm \&:hash
1168Compute a 32bit hash of the value and encode it as hex digits.
1169.It Cm \&:localtime
1170The value is a format string for
1171.Xr strftime 3 ,
1172using the current
1173.Xr localtime 3 .
1174.It Cm \&:tA
1175Attempt to convert variable to an absolute path using
1176.Xr realpath 3 ,
1177if that fails, the value is unchanged.
1178.It Cm \&:tl
1179Converts variable to lower-case letters.
1180.It Cm \&:ts Ns Ar c
1181Words in the variable are normally separated by a space on expansion.
1182This modifier sets the separator to the character
1183.Ar c .
1184If
1185.Ar c
1186is omitted, then no separator is used.
1187The common escapes (including octal numeric codes), work as expected.
1188.It Cm \&:tu
1189Converts variable to upper-case letters.
1190.It Cm \&:tW
1191Causes the value to be treated as a single word
1192(possibly containing embedded white space).
1193See also
1194.Ql Cm \&:[*] .
1195.It Cm \&:tw
1196Causes the value to be treated as a sequence of
1197words delimited by white space.
1198See also
1199.Ql Cm \&:[@] .
1200.Sm off
1201.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1202.Sm on
1203Modify the first occurrence of
1204.Ar old_string
1205in the variable's value, replacing it with
1206.Ar new_string .
1207If a
1208.Ql g
1209is appended to the last slash of the pattern, all occurrences
1210in each word are replaced.
1211If a
1212.Ql 1
1213is appended to the last slash of the pattern, only the first word
1214is affected.
1215If a
1216.Ql W
1217is appended to the last slash of the pattern,
1218then the value is treated as a single word
1219(possibly containing embedded white space).
1220If
1221.Ar old_string
1222begins with a caret
1223.Pq Ql ^ ,
1224.Ar old_string
1225is anchored at the beginning of each word.
1226If
1227.Ar old_string
1228ends with a dollar sign
1229.Pq Ql \&$ ,
1230it is anchored at the end of each word.
1231Inside
1232.Ar new_string ,
1233an ampersand
1234.Pq Ql \*[Am]
1235is replaced by
1236.Ar old_string
1237(without any
1238.Ql ^
1239or
1240.Ql \&$ ) .
1241Any character may be used as a delimiter for the parts of the modifier
1242string.
1243The anchoring, ampersand and delimiter characters may be escaped with a
1244backslash
1245.Pq Ql \e .
1246.Pp
1247Variable expansion occurs in the normal fashion inside both
1248.Ar old_string
1249and
1250.Ar new_string
1251with the single exception that a backslash is used to prevent the expansion
1252of a dollar sign
1253.Pq Ql \&$ ,
1254not a preceding dollar sign as is usual.
1255.Sm off
1256.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1257.Sm on
1258The
1259.Cm \&:C
1260modifier is just like the
1261.Cm \&:S
1262modifier except that the old and new strings, instead of being
1263simple strings, are an extended regular expression (see
1264.Xr regex 3 )
1265string
1266.Ar pattern
1267and an
1268.Xr ed 1 Ns \-style
1269string
1270.Ar replacement .
1271Normally, the first occurrence of the pattern
1272.Ar pattern
1273in each word of the value is substituted with
1274.Ar replacement .
1275The
1276.Ql 1
1277modifier causes the substitution to apply to at most one word; the
1278.Ql g
1279modifier causes the substitution to apply to as many instances of the
1280search pattern
1281.Ar pattern
1282as occur in the word or words it is found in; the
1283.Ql W
1284modifier causes the value to be treated as a single word
1285(possibly containing embedded white space).
1286Note that
1287.Ql 1
1288and
1289.Ql g
1290are orthogonal; the former specifies whether multiple words are
1291potentially affected, the latter whether multiple substitutions can
1292potentially occur within each affected word.
1293.Pp
1294As for the
1295.Cm \&:S
1296modifier, the
1297.Ar pattern
1298and
1299.Ar replacement
1300are subjected to variable expansion before being parsed as
1301regular expressions.
1302.It Cm \&:T
1303Replaces each word in the variable with its last component.
1304.It Cm \&:u
1305Remove adjacent duplicate words (like
1306.Xr uniq 1 ) .
1307.Sm off
1308.It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1309.Sm on
1310If the variable name (not its value), when parsed as a .if conditional
1311expression, evaluates to true, return as its value the
1312.Ar true_string ,
1313otherwise return the
1314.Ar false_string .
1315Since the variable name is used as the expression, \&:\&? must be the
1316first modifier after the variable name itself - which will, of course,
1317usually contain variable expansions.
1318A common error is trying to use expressions like
1319.Dl ${NUMBERS:M42:?match:no}
1320which actually tests defined(NUMBERS),
1321to determine is any words match "42" you need to use something like:
1322.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1323.It Ar :old_string=new_string
1324This is the
1325.At V
1326style variable substitution.
1327It must be the last modifier specified.
1328If
1329.Ar old_string
1330or
1331.Ar new_string
1332do not contain the pattern matching character
1333.Ar %
1334then it is assumed that they are
1335anchored at the end of each word, so only suffixes or entire
1336words may be replaced.
1337Otherwise
1338.Ar %
1339is the substring of
1340.Ar old_string
1341to be replaced in
1342.Ar new_string .
1343.Pp
1344Variable expansion occurs in the normal fashion inside both
1345.Ar old_string
1346and
1347.Ar new_string
1348with the single exception that a backslash is used to prevent the
1349expansion of a dollar sign
1350.Pq Ql \&$ ,
1351not a preceding dollar sign as is usual.
1352.Sm off
1353.It Cm \&:@ Ar temp Cm @ Ar string Cm @
1354.Sm on
1355This is the loop expansion mechanism from the OSF Development
1356Environment (ODE) make.
1357Unlike
1358.Cm \&.for
1359loops expansion occurs at the time of
1360reference.
1361Assign
1362.Ar temp
1363to each word in the variable and evaluate
1364.Ar string .
1365The ODE convention is that
1366.Ar temp
1367should start and end with a period.
1368For example.
1369.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1370.Pp
1371However a single character variable is often more readable:
1372.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1373.It Cm \&:U Ns Ar newval
1374If the variable is undefined
1375.Ar newval
1376is the value.
1377If the variable is defined, the existing value is returned.
1378This is another ODE make feature.
1379It is handy for setting per-target CFLAGS for instance:
1380.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1381If a value is only required if the variable is undefined, use:
1382.Dl ${VAR:D:Unewval}
1383.It Cm \&:D Ns Ar newval
1384If the variable is defined
1385.Ar newval
1386is the value.
1387.It Cm \&:L
1388The name of the variable is the value.
1389.It Cm \&:P
1390The path of the node which has the same name as the variable
1391is the value.
1392If no such node exists or its path is null, then the
1393name of the variable is used.
1394In order for this modifier to work, the name (node) must at least have
1395appeared on the rhs of a dependency.
1396.Sm off
1397.It Cm \&:\&! Ar cmd Cm \&!
1398.Sm on
1399The output of running
1400.Ar cmd
1401is the value.
1402.It Cm \&:sh
1403If the variable is non-empty it is run as a command and the output
1404becomes the new value.
1405.It Cm \&::= Ns Ar str
1406The variable is assigned the value
1407.Ar str
1408after substitution.
1409This modifier and its variations are useful in
1410obscure situations such as wanting to set a variable when shell commands
1411are being parsed.
1412These assignment modifiers always expand to
1413nothing, so if appearing in a rule line by themselves should be
1414preceded with something to keep
1415.Nm
1416happy.
1417.Pp
1418The
1419.Ql Cm \&::
1420helps avoid false matches with the
1421.At V
1422style
1423.Cm \&:=
1424modifier and since substitution always occurs the
1425.Cm \&::=
1426form is vaguely appropriate.
1427.It Cm \&::?= Ns Ar str
1428As for
1429.Cm \&::=
1430but only if the variable does not already have a value.
1431.It Cm \&::+= Ns Ar str
1432Append
1433.Ar str
1434to the variable.
1435.It Cm \&::!= Ns Ar cmd
1436Assign the output of
1437.Ar cmd
1438to the variable.
1439.It Cm \&:\&[ Ns Ar range Ns Cm \&]
1440Selects one or more words from the value,
1441or performs other operations related to the way in which the
1442value is divided into words.
1443.Pp
1444Ordinarily, a value is treated as a sequence of words
1445delimited by white space.
1446Some modifiers suppress this behaviour,
1447causing a value to be treated as a single word
1448(possibly containing embedded white space).
1449An empty value, or a value that consists entirely of white-space,
1450is treated as a single word.
1451For the purposes of the
1452.Ql Cm \&:[]
1453modifier, the words are indexed both forwards using positive integers
1454(where index 1 represents the first word),
1455and backwards using negative integers
1456(where index \-1 represents the last word).
1457.Pp
1458The
1459.Ar range
1460is subjected to variable expansion, and the expanded result is
1461then interpreted as follows:
1462.Bl -tag -width index
1463.\" :[n]
1464.It Ar index
1465Selects a single word from the value.
1466.\" :[start..end]
1467.It Ar start Ns Cm \&.. Ns Ar end
1468Selects all words from
1469.Ar start
1470to
1471.Ar end ,
1472inclusive.
1473For example,
1474.Ql Cm \&:[2..-1]
1475selects all words from the second word to the last word.
1476If
1477.Ar start
1478is greater than
1479.Ar end ,
1480then the words are output in reverse order.
1481For example,
1482.Ql Cm \&:[-1..1]
1483selects all the words from last to first.
1484.\" :[*]
1485.It Cm \&*
1486Causes subsequent modifiers to treat the value as a single word
1487(possibly containing embedded white space).
1488Analogous to the effect of
1489\&"$*\&"
1490in Bourne shell.
1491.\" :[0]
1492.It 0
1493Means the same as
1494.Ql Cm \&:[*] .
1495.\" :[*]
1496.It Cm \&@
1497Causes subsequent modifiers to treat the value as a sequence of words
1498delimited by white space.
1499Analogous to the effect of
1500\&"$@\&"
1501in Bourne shell.
1502.\" :[#]
1503.It Cm \&#
1504Returns the number of words in the value.
1505.El \" :[range]
1506.El
1507.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1508Makefile inclusion, conditional structures and for loops  reminiscent
1509of the C programming language are provided in
1510.Nm .
1511All such structures are identified by a line beginning with a single
1512dot
1513.Pq Ql \&.
1514character.
1515Files are included with either
1516.Cm \&.include Aq Ar file
1517or
1518.Cm \&.include Pf \*q Ar file Ns \*q .
1519Variables between the angle brackets or double quotes are expanded
1520to form the file name.
1521If angle brackets are used, the included makefile is expected to be in
1522the system makefile directory.
1523If double quotes are used, the including makefile's directory and any
1524directories specified using the
1525.Fl I
1526option are searched before the system
1527makefile directory.
1528For compatibility with other versions of
1529.Nm
1530.Ql include file ...
1531is also accepted.
1532If the include statement is written as
1533.Cm .-include
1534or as
1535.Cm .sinclude
1536then errors locating and/or opening include files are ignored.
1537.Pp
1538Conditional expressions are also preceded by a single dot as the first
1539character of a line.
1540The possible conditionals are as follows:
1541.Bl -tag -width Ds
1542.It Ic .error Ar message
1543The message is printed along with the name of the makefile and line number,
1544then
1545.Nm
1546will exit.
1547.It Ic .export Ar variable ...
1548Export the specified global variable.
1549If no variable list is provided, all globals are exported
1550except for internal variables (those that start with
1551.Ql \&. ) .
1552This is not affected by the
1553.Fl X
1554flag, so should be used with caution.
1555For compatibility with other
1556.Nm
1557programs
1558.Ql export variable=value
1559is also accepted.
1560.Pp
1561Appending a variable name to
1562.Va .MAKE.EXPORTED
1563is equivalent to exporting a variable.
1564.It Ic .export-env Ar variable ...
1565The same as
1566.Ql .export ,
1567except that the variable is not appended to
1568.Va .MAKE.EXPORTED .
1569This allows exporting a value to the environment which is different from that
1570used by
1571.Nm
1572internally.
1573.It Ic .info Ar message
1574The message is printed along with the name of the makefile and line number.
1575.It Ic .undef Ar variable
1576Un-define the specified global variable.
1577Only global variables may be un-defined.
1578.It Ic .unexport Ar variable ...
1579The opposite of
1580.Ql .export .
1581The specified global
1582.Va variable
1583will be removed from
1584.Va .MAKE.EXPORTED .
1585If no variable list is provided, all globals are unexported,
1586and
1587.Va .MAKE.EXPORTED
1588deleted.
1589.It Ic .unexport-env
1590Unexport all globals previously exported and
1591clear the environment inherited from the parent.
1592This operation will cause a memory leak of the original environment,
1593so should be used sparingly.
1594Testing for
1595.Va .MAKE.LEVEL
1596being 0, would make sense.
1597Also note that any variables which originated in the parent environment
1598should be explicitly preserved if desired.
1599For example:
1600.Bd -literal -offset indent
1601.Li .if ${.MAKE.LEVEL} == 0
1602PATH := ${PATH}
1603.Li .unexport-env
1604.Li .export PATH
1605.Li .endif
1606.Pp
1607.Ed
1608Would result in an environment containing only
1609.Ql Ev PATH ,
1610which is the minimal useful environment.
1611Actually
1612.Ql Ev .MAKE.LEVEL
1613will also be pushed into the new environment.
1614.It Ic .warning Ar message
1615The message prefixed by
1616.Ql Pa warning:
1617is printed along with the name of the makefile and line number.
1618.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1619Test the value of an expression.
1620.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1621Test the value of a variable.
1622.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1623Test the value of a variable.
1624.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1625Test the target being built.
1626.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1627Test the target being built.
1628.It Ic .else
1629Reverse the sense of the last conditional.
1630.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1631A combination of
1632.Ql Ic .else
1633followed by
1634.Ql Ic .if .
1635.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1636A combination of
1637.Ql Ic .else
1638followed by
1639.Ql Ic .ifdef .
1640.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1641A combination of
1642.Ql Ic .else
1643followed by
1644.Ql Ic .ifndef .
1645.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1646A combination of
1647.Ql Ic .else
1648followed by
1649.Ql Ic .ifmake .
1650.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1651A combination of
1652.Ql Ic .else
1653followed by
1654.Ql Ic .ifnmake .
1655.It Ic .endif
1656End the body of the conditional.
1657.El
1658.Pp
1659The
1660.Ar operator
1661may be any one of the following:
1662.Bl -tag -width "Cm XX"
1663.It Cm \&|\&|
1664Logical OR.
1665.It Cm \&\*[Am]\*[Am]
1666Logical
1667.Tn AND ;
1668of higher precedence than
1669.Dq \&|\&| .
1670.El
1671.Pp
1672As in C,
1673.Nm
1674will only evaluate a conditional as far as is necessary to determine
1675its value.
1676Parentheses may be used to change the order of evaluation.
1677The boolean operator
1678.Ql Ic \&!
1679may be used to logically negate an entire
1680conditional.
1681It is of higher precedence than
1682.Ql Ic \&\*[Am]\*[Am] .
1683.Pp
1684The value of
1685.Ar expression
1686may be any of the following:
1687.Bl -tag -width defined
1688.It Ic defined
1689Takes a variable name as an argument and evaluates to true if the variable
1690has been defined.
1691.It Ic make
1692Takes a target name as an argument and evaluates to true if the target
1693was specified as part of
1694.Nm Ns 's
1695command line or was declared the default target (either implicitly or
1696explicitly, see
1697.Va .MAIN )
1698before the line containing the conditional.
1699.It Ic empty
1700Takes a variable, with possible modifiers, and evaluates to true if
1701the expansion of the variable would result in an empty string.
1702.It Ic exists
1703Takes a file name as an argument and evaluates to true if the file exists.
1704The file is searched for on the system search path (see
1705.Va .PATH ) .
1706.It Ic target
1707Takes a target name as an argument and evaluates to true if the target
1708has been defined.
1709.It Ic commands
1710Takes a target name as an argument and evaluates to true if the target
1711has been defined and has commands associated with it.
1712.El
1713.Pp
1714.Ar Expression
1715may also be an arithmetic or string comparison.
1716Variable expansion is
1717performed on both sides of the comparison, after which the integral
1718values are compared.
1719A value is interpreted as hexadecimal if it is
1720preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1721The standard C relational operators are all supported.
1722If after
1723variable expansion, either the left or right hand side of a
1724.Ql Ic ==
1725or
1726.Ql Ic "!="
1727operator is not an integral value, then
1728string comparison is performed between the expanded
1729variables.
1730If no relational operator is given, it is assumed that the expanded
1731variable is being compared against 0 or an empty string in the case
1732of a string comparison.
1733.Pp
1734When
1735.Nm
1736is evaluating one of these conditional expressions, and it encounters
1737a (white-space separated) word it doesn't recognize, either the
1738.Dq make
1739or
1740.Dq defined
1741expression is applied to it, depending on the form of the conditional.
1742If the form is
1743.Ql Ic .ifdef ,
1744.Ql Ic .ifndef ,
1745or
1746.Ql Ic .if
1747the
1748.Dq defined
1749expression is applied.
1750Similarly, if the form is
1751.Ql Ic .ifmake
1752or
1753.Ql Ic .ifnmake , the
1754.Dq make
1755expression is applied.
1756.Pp
1757If the conditional evaluates to true the parsing of the makefile continues
1758as before.
1759If it evaluates to false, the following lines are skipped.
1760In both cases this continues until a
1761.Ql Ic .else
1762or
1763.Ql Ic .endif
1764is found.
1765.Pp
1766For loops are typically used to apply a set of rules to a list of files.
1767The syntax of a for loop is:
1768.Pp
1769.Bl -tag -compact -width Ds
1770.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1771.It Aq make-rules
1772.It Ic \&.endfor
1773.El
1774.Pp
1775After the for
1776.Ic expression
1777is evaluated, it is split into words.
1778On each iteration of the loop, one word is taken and assigned to each
1779.Ic variable ,
1780in order, and these
1781.Ic variables
1782are substituted into the
1783.Ic make-rules
1784inside the body of the for loop.
1785The number of words must come out even; that is, if there are three
1786iteration variables, the number of words provided must be a multiple
1787of three.
1788.Sh COMMENTS
1789Comments begin with a hash
1790.Pq Ql \&#
1791character, anywhere but in a shell
1792command line, and continue to the end of an unescaped new line.
1793.Sh SPECIAL SOURCES (ATTRIBUTES)
1794.Bl -tag -width .IGNOREx
1795.It Ic .EXEC
1796Target is never out of date, but always execute commands anyway.
1797.It Ic .IGNORE
1798Ignore any errors from the commands associated with this target, exactly
1799as if they all were preceded by a dash
1800.Pq Ql \- .
1801.\" .It Ic .INVISIBLE
1802.\" XXX
1803.\" .It Ic .JOIN
1804.\" XXX
1805.It Ic .MADE
1806Mark all sources of this target as being up-to-date.
1807.It Ic .MAKE
1808Execute the commands associated with this target even if the
1809.Fl n
1810or
1811.Fl t
1812options were specified.
1813Normally used to mark recursive
1814.Nm Ns s .
1815.It Ic .META
1816Create a meta file for the target, even if it is flagged as
1817.Ic .PHONY ,
1818.Ic .MAKE ,
1819or
1820.Ic .SPECIAL .
1821Usage in conjunction with
1822.Ic .MAKE
1823is the most likely case.
1824In "meta" mode, the target is out-of-date if the meta file is missing.
1825.It Ic .NOMETA
1826Do not create a meta file for the target.
1827Meta files are also not created for
1828.Ic .PHONY ,
1829.Ic .MAKE ,
1830or
1831.Ic .SPECIAL
1832targets.
1833.It Ic .NOMETA_CMP
1834Ignore differences in commands when deciding if target is out of date.
1835This is useful if the command contains a value which always changes.
1836If the number of commands change, though, the target will still be out of date.
1837The same effect applies to any command line that uses the variable
1838.Va .OODATE ,
1839which can be used for that purpose even when not otherwise needed or desired:
1840.Bd -literal -offset indent
1841
1842skip-compare-for-some:
1843	@echo this will be compared
1844	@echo this will not ${.OODATE:M.NOMETA_CMP}
1845	@echo this will also be compared
1846
1847.Ed
1848The
1849.Cm \&:M
1850pattern suppresses any expansion of the unwanted variable.
1851.It Ic .NOPATH
1852Do not search for the target in the directories specified by
1853.Ic .PATH .
1854.It Ic .NOTMAIN
1855Normally
1856.Nm
1857selects the first target it encounters as the default target to be built
1858if no target was specified.
1859This source prevents this target from being selected.
1860.It Ic .OPTIONAL
1861If a target is marked with this attribute and
1862.Nm
1863can't figure out how to create it, it will ignore this fact and assume
1864the file isn't needed or already exists.
1865.It Ic .PHONY
1866The target does not
1867correspond to an actual file; it is always considered to be out of date,
1868and will not be created with the
1869.Fl t
1870option.
1871Suffix-transformation rules are not applied to
1872.Ic .PHONY
1873targets.
1874.It Ic .PRECIOUS
1875When
1876.Nm
1877is interrupted, it normally removes any partially made targets.
1878This source prevents the target from being removed.
1879.It Ic .RECURSIVE
1880Synonym for
1881.Ic .MAKE .
1882.It Ic .SILENT
1883Do not echo any of the commands associated with this target, exactly
1884as if they all were preceded by an at sign
1885.Pq Ql @ .
1886.It Ic .USE
1887Turn the target into
1888.Nm Ns 's
1889version of a macro.
1890When the target is used as a source for another target, the other target
1891acquires the commands, sources, and attributes (except for
1892.Ic .USE )
1893of the
1894source.
1895If the target already has commands, the
1896.Ic .USE
1897target's commands are appended
1898to them.
1899.It Ic .USEBEFORE
1900Exactly like
1901.Ic .USE ,
1902but prepend the
1903.Ic .USEBEFORE
1904target commands to the target.
1905.It Ic .WAIT
1906If
1907.Ic .WAIT
1908appears in a dependency line, the sources that precede it are
1909made before the sources that succeed it in the line.
1910Since the dependents of files are not made until the file itself
1911could be made, this also stops the dependents being built unless they
1912are needed for another branch of the dependency tree.
1913So given:
1914.Bd -literal
1915x: a .WAIT b
1916	echo x
1917a:
1918	echo a
1919b: b1
1920	echo b
1921b1:
1922	echo b1
1923
1924.Ed
1925the output is always
1926.Ql a ,
1927.Ql b1 ,
1928.Ql b ,
1929.Ql x .
1930.br
1931The ordering imposed by
1932.Ic .WAIT
1933is only relevant for parallel makes.
1934.El
1935.Sh SPECIAL TARGETS
1936Special targets may not be included with other targets, i.e. they must be
1937the only target specified.
1938.Bl -tag -width .BEGINx
1939.It Ic .BEGIN
1940Any command lines attached to this target are executed before anything
1941else is done.
1942.It Ic .DEFAULT
1943This is sort of a
1944.Ic .USE
1945rule for any target (that was used only as a
1946source) that
1947.Nm
1948can't figure out any other way to create.
1949Only the shell script is used.
1950The
1951.Ic .IMPSRC
1952variable of a target that inherits
1953.Ic .DEFAULT Ns 's
1954commands is set
1955to the target's own name.
1956.It Ic .END
1957Any command lines attached to this target are executed after everything
1958else is done.
1959.It Ic .ERROR
1960Any command lines attached to this target are executed when another target fails.
1961The
1962.Ic .ERROR_TARGET
1963variable is set to the target that failed.
1964See also
1965.Ic MAKE_PRINT_VAR_ON_ERROR .
1966.It Ic .IGNORE
1967Mark each of the sources with the
1968.Ic .IGNORE
1969attribute.
1970If no sources are specified, this is the equivalent of specifying the
1971.Fl i
1972option.
1973.It Ic .INTERRUPT
1974If
1975.Nm
1976is interrupted, the commands for this target will be executed.
1977.It Ic .MAIN
1978If no target is specified when
1979.Nm
1980is invoked, this target will be built.
1981.It Ic .MAKEFLAGS
1982This target provides a way to specify flags for
1983.Nm
1984when the makefile is used.
1985The flags are as if typed to the shell, though the
1986.Fl f
1987option will have
1988no effect.
1989.\" XXX: NOT YET!!!!
1990.\" .It Ic .NOTPARALLEL
1991.\" The named targets are executed in non parallel mode.
1992.\" If no targets are
1993.\" specified, then all targets are executed in non parallel mode.
1994.It Ic .NOPATH
1995Apply the
1996.Ic .NOPATH
1997attribute to any specified sources.
1998.It Ic .NOTPARALLEL
1999Disable parallel mode.
2000.It Ic .NO_PARALLEL
2001Synonym for
2002.Ic .NOTPARALLEL ,
2003for compatibility with other pmake variants.
2004.It Ic .ORDER
2005The named targets are made in sequence.
2006This ordering does not add targets to the list of targets to be made.
2007Since the dependents of a target do not get built until the target itself
2008could be built, unless
2009.Ql a
2010is built by another part of the dependency graph,
2011the following is a dependency loop:
2012.Bd -literal
2013\&.ORDER: b a
2014b: a
2015.Ed
2016.Pp
2017The ordering imposed by
2018.Ic .ORDER
2019is only relevant for parallel makes.
2020.\" XXX: NOT YET!!!!
2021.\" .It Ic .PARALLEL
2022.\" The named targets are executed in parallel mode.
2023.\" If no targets are
2024.\" specified, then all targets are executed in parallel mode.
2025.It Ic .PATH
2026The sources are directories which are to be searched for files not
2027found in the current directory.
2028If no sources are specified, any previously specified directories are
2029deleted.
2030If the source is the special
2031.Ic .DOTLAST
2032target, then the current working
2033directory is searched last.
2034.It Ic .PATH. Ns Va suffix
2035Like
2036.Ic .PATH
2037but applies only to files with a particular suffix.
2038The suffix must have been previously declared with
2039.Ic .SUFFIXES .
2040.It Ic .PHONY
2041Apply the
2042.Ic .PHONY
2043attribute to any specified sources.
2044.It Ic .PRECIOUS
2045Apply the
2046.Ic .PRECIOUS
2047attribute to any specified sources.
2048If no sources are specified, the
2049.Ic .PRECIOUS
2050attribute is applied to every
2051target in the file.
2052.It Ic .SHELL
2053Sets the shell that
2054.Nm
2055will use to execute commands.
2056The sources are a set of
2057.Ar field=value
2058pairs.
2059.Bl -tag -width hasErrCtls
2060.It Ar name
2061This is the minimal specification, used to select one of the builtin
2062shell specs;
2063.Ar sh ,
2064.Ar ksh ,
2065and
2066.Ar csh .
2067.It Ar path
2068Specifies the path to the shell.
2069.It Ar hasErrCtl
2070Indicates whether the shell supports exit on error.
2071.It Ar check
2072The command to turn on error checking.
2073.It Ar ignore
2074The command to disable error checking.
2075.It Ar echo
2076The command to turn on echoing of commands executed.
2077.It Ar quiet
2078The command to turn off echoing of commands executed.
2079.It Ar filter
2080The output to filter after issuing the
2081.Ar quiet
2082command.
2083It is typically identical to
2084.Ar quiet .
2085.It Ar errFlag
2086The flag to pass the shell to enable error checking.
2087.It Ar echoFlag
2088The flag to pass the shell to enable command echoing.
2089.It Ar newline
2090The string literal to pass the shell that results in a single newline
2091character when used outside of any quoting characters.
2092.El
2093Example:
2094.Bd -literal
2095\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2096	check="set \-e" ignore="set +e" \e
2097	echo="set \-v" quiet="set +v" filter="set +v" \e
2098	echoFlag=v errFlag=e newline="'\en'"
2099.Ed
2100.It Ic .SILENT
2101Apply the
2102.Ic .SILENT
2103attribute to any specified sources.
2104If no sources are specified, the
2105.Ic .SILENT
2106attribute is applied to every
2107command in the file.
2108.It Ic .STALE
2109This target gets run when a dependency file contains stale entries, having
2110.Va .ALLSRC
2111set to the name of that dependency file.
2112.It Ic .SUFFIXES
2113Each source specifies a suffix to
2114.Nm .
2115If no sources are specified, any previously specified suffixes are deleted.
2116It allows the creation of suffix-transformation rules.
2117.Pp
2118Example:
2119.Bd -literal
2120\&.SUFFIXES: .o
2121\&.c.o:
2122	cc \-o ${.TARGET} \-c ${.IMPSRC}
2123.Ed
2124.El
2125.Sh ENVIRONMENT
2126.Nm
2127uses the following environment variables, if they exist:
2128.Ev MACHINE ,
2129.Ev MACHINE_ARCH ,
2130.Ev MAKE ,
2131.Ev MAKEFLAGS ,
2132.Ev MAKEOBJDIR ,
2133.Ev MAKEOBJDIRPREFIX ,
2134.Ev MAKESYSPATH ,
2135.Ev PWD ,
2136and
2137.Ev TMPDIR .
2138.Pp
2139.Ev MAKEOBJDIRPREFIX
2140and
2141.Ev MAKEOBJDIR
2142may only be set in the environment or on the command line to
2143.Nm
2144and not as makefile variables;
2145see the description of
2146.Ql Va .OBJDIR
2147for more details.
2148.Sh FILES
2149.Bl -tag -width /usr/share/mk -compact
2150.It .depend
2151list of dependencies
2152.It Makefile
2153list of dependencies
2154.It makefile
2155list of dependencies
2156.It sys.mk
2157system makefile
2158.It /usr/share/mk
2159system makefile directory
2160.El
2161.Sh COMPATIBILITY
2162The basic make syntax is compatible between different versions of make;
2163however the special variables, variable modifiers and conditionals are not.
2164.Ss Older versions
2165An incomplete list of changes in older versions of
2166.Nm :
2167.Pp
2168The way that .for loop variables are substituted changed after
2169NetBSD 5.0
2170so that they still appear to be variable expansions.
2171In particular this stops them being treated as syntax, and removes some
2172obscure problems using them in .if statements.
2173.Pp
2174The way that parallel makes are scheduled changed in
2175NetBSD 4.0
2176so that .ORDER and .WAIT apply recursively to the dependent nodes.
2177The algorithms used may change again in the future.
2178.Ss Other make dialects
2179Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
2180support most of the features of
2181.Nm
2182as described in this manual.
2183Most notably:
2184.Bl -bullet -offset indent
2185.It
2186The
2187.Ic .WAIT
2188and
2189.Ic .ORDER
2190declarations and most functionality pertaining to parallelization.
2191(GNU make supports parallelization but lacks these features needed to
2192control it effectively.)
2193.It
2194Directives, including for loops and conditionals and most of the
2195forms of include files.
2196(GNU make has its own incompatible and less powerful syntax for
2197conditionals.)
2198.It
2199All built-in variables that begin with a dot.
2200.It
2201Most of the special sources and targets that begin with a dot,
2202with the notable exception of
2203.Ic .PHONY ,
2204.Ic .PRECIOUS ,
2205and
2206.Ic .SUFFIXES .
2207.It
2208Variable modifiers, except for the
2209.Dl :old=new
2210string substitution, which does not portably support globbing with
2211.Ql %
2212and historically only works on declared suffixes.
2213.It
2214The
2215.Ic $>
2216variable even in its short form; most makes support this functionality
2217but its name varies.
2218.El
2219.Pp
2220Some features are somewhat more portable, such as assignment with
2221.Ic += ,
2222.Ic ?= ,
2223and
2224.Ic != .
2225The
2226.Ic .PATH
2227functionality is based on an older feature
2228.Ic VPATH
2229found in GNU make and many versions of SVR4 make; however,
2230historically its behavior is too ill-defined (and too buggy) to rely
2231upon.
2232.Pp
2233The
2234.Ic $@
2235and
2236.Ic $<
2237variables are more or less universally portable, as is the
2238.Ic $(MAKE)
2239variable.
2240Basic use of suffix rules (for files only in the current directory,
2241not trying to chain transformations together, etc.) is also reasonably
2242portable.
2243.Sh SEE ALSO
2244.Xr mkdep 1
2245.Sh HISTORY
2246.Nm
2247is derived from NetBSD
2248.Xr make 1 .
2249It uses autoconf to facilitate portability to other platforms.
2250.Pp
2251A
2252make
2253command appeared in
2254.At v7 .
2255This
2256make
2257implementation is based on Adam De Boor's pmake program which was written
2258for Sprite at Berkeley.
2259It was designed to be a parallel distributed make running jobs on different
2260machines using a daemon called
2261.Dq customs .
2262.Pp
2263Historically the target/dependency
2264.Dq FRC
2265has been used to FoRCe rebuilding (since the target/dependency
2266does not exist... unless someone creates an
2267.Dq FRC
2268file).
2269.Sh BUGS
2270The
2271make
2272syntax is difficult to parse without actually acting of the data.
2273For instance finding the end of a variable use should involve scanning each
2274the modifiers using the correct terminator for each field.
2275In many places
2276make
2277just counts {} and () in order to find the end of a variable expansion.
2278.Pp
2279There is no way of escaping a space character in a filename.
2280