xref: /freebsd/contrib/bmake/make.1 (revision 43faedc1339a9624c7acedb7f3e5624e64da5b99)
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3.\" Copyright (c) 1990, 1993
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30.\"	from: @(#)make.1	8.4 (Berkeley) 3/19/94
31.\"
32.Dd June 4, 2015
33.Dt MAKE 1
34.Os
35.Sh NAME
36.Nm make
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.ALWAYS_PASS_JOB_QUEUE
769Tells
770.Nm
771whether to pass the descriptors of the job token queue
772even if the target is not tagged with
773.Ic .MAKE
774The default is
775.Ql Pa yes
776for backwards compatability with
777.Fx 9.0
778and earlier.
779.It Va .MAKE.DEPENDFILE
780Names the makefile (default
781.Ql Pa .depend )
782from which generated dependencies are read.
783.It Va .MAKE.EXPAND_VARIABLES
784A boolean that controls the default behavior of the
785.Fl V
786option.
787.It Va .MAKE.EXPORTED
788The list of variables exported by
789.Nm .
790.It Va .MAKE.JOBS
791The argument to the
792.Fl j
793option.
794.It Va .MAKE.JOB.PREFIX
795If
796.Nm
797is run with
798.Ar j
799then output for each target is prefixed with a token
800.Ql --- target ---
801the first part of which can be controlled via
802.Va .MAKE.JOB.PREFIX .
803If
804.Va .MAKE.JOB.PREFIX
805is empty, no token is printed.
806.br
807For example:
808.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
809would produce tokens like
810.Ql ---make[1234] target ---
811making it easier to track the degree of parallelism being achieved.
812.It Ev MAKEFLAGS
813The environment variable
814.Ql Ev MAKEFLAGS
815may contain anything that
816may be specified on
817.Nm Ns 's
818command line.
819Anything specified on
820.Nm Ns 's
821command line is appended to the
822.Ql Ev MAKEFLAGS
823variable which is then
824entered into the environment for all programs which
825.Nm
826executes.
827.It Va .MAKE.LEVEL
828The recursion depth of
829.Nm .
830The initial instance of
831.Nm
832will be 0, and an incremented value is put into the environment
833to be seen by the next generation.
834This allows tests like:
835.Li .if ${.MAKE.LEVEL} == 0
836to protect things which should only be evaluated in the initial instance of
837.Nm .
838.It Va .MAKE.MAKEFILE_PREFERENCE
839The ordered list of makefile names
840(default
841.Ql Pa makefile ,
842.Ql Pa Makefile )
843that
844.Nm
845will look for.
846.It Va .MAKE.MAKEFILES
847The list of makefiles read by
848.Nm ,
849which is useful for tracking dependencies.
850Each makefile is recorded only once, regardless of the number of times read.
851.It Va .MAKE.MODE
852Processed after reading all makefiles.
853Can affect the mode that
854.Nm
855runs in.
856It can contain a number of keywords:
857.Bl -hang -width ignore-cmd
858.It Pa compat
859Like
860.Fl B ,
861puts
862.Nm
863into "compat" mode.
864.It Pa meta
865Puts
866.Nm
867into "meta" mode, where meta files are created for each target
868to capture the command run, the output generated and if
869.Xr filemon 4
870is available, the system calls which are of interest to
871.Nm .
872The captured output can be very useful when diagnosing errors.
873.It Pa curdirOk= Ar bf
874Normally
875.Nm
876will not create .meta files in
877.Ql Va .CURDIR .
878This can be overridden by setting
879.Va bf
880to a value which represents True.
881.It Pa env
882For debugging, it can be useful to inlcude the environment
883in the .meta file.
884.It Pa verbose
885If in "meta" mode, print a clue about the target being built.
886This is useful if the build is otherwise running silently.
887The message printed the value of:
888.Va .MAKE.META.PREFIX .
889.It Pa ignore-cmd
890Some makefiles have commands which are simply not stable.
891This keyword causes them to be ignored for
892determining whether a target is out of date in "meta" mode.
893See also
894.Ic .NOMETA_CMP .
895.It Pa silent= Ar bf
896If
897.Va bf
898is True, when a .meta file is created, mark the target
899.Ic .SILENT .
900.El
901.It Va .MAKE.META.BAILIWICK
902In "meta" mode, provides a list of prefixes which
903match the directories controlled by
904.Nm .
905If a file that was generated outside of
906.Va .OBJDIR
907but within said bailiwick is missing,
908the current target is considered out-of-date.
909.It Va .MAKE.META.CREATED
910In "meta" mode, this variable contains a list of all the meta files
911updated.
912If not empty, it can be used to trigger processing of
913.Va .MAKE.META.FILES .
914.It Va .MAKE.META.FILES
915In "meta" mode, this variable contains a list of all the meta files
916used (updated or not).
917This list can be used to process the meta files to extract dependency
918information.
919.It Va .MAKE.META.IGNORE_PATHS
920Provides a list of path prefixes that should be ignored;
921because the contents are expected to change over time.
922The default list includes:
923.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
924.It Va .MAKE.META.PREFIX
925Defines the message printed for each meta file updated in "meta verbose" mode.
926The default value is:
927.Dl Building ${.TARGET:H:tA}/${.TARGET:T}
928.It Va .MAKEOVERRIDES
929This variable is used to record the names of variables assigned to
930on the command line, so that they may be exported as part of
931.Ql Ev MAKEFLAGS .
932This behaviour can be disabled by assigning an empty value to
933.Ql Va .MAKEOVERRIDES
934within a makefile.
935Extra variables can be exported from a makefile
936by appending their names to
937.Ql Va .MAKEOVERRIDES .
938.Ql Ev MAKEFLAGS
939is re-exported whenever
940.Ql Va .MAKEOVERRIDES
941is modified.
942.It Va .MAKE.PATH_FILEMON
943If
944.Nm
945was built with
946.Xr filemon 4
947support, this is set to the path of the device node.
948This allows makefiles to test for this support.
949.It Va .MAKE.PID
950The process-id of
951.Nm .
952.It Va .MAKE.PPID
953The parent process-id of
954.Nm .
955.It Va MAKE_PRINT_VAR_ON_ERROR
956When
957.Nm
958stops due to an error, it prints its name and the value of
959.Ql Va .CURDIR
960as well as the value of any variables named in
961.Ql Va MAKE_PRINT_VAR_ON_ERROR .
962.It Va .newline
963This variable is simply assigned a newline character as its value.
964This allows expansions using the
965.Cm \&:@
966modifier to put a newline between
967iterations of the loop rather than a space.
968For example, the printing of
969.Ql Va MAKE_PRINT_VAR_ON_ERROR
970could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
971.It Va .OBJDIR
972A path to the directory where the targets are built.
973Its value is determined by trying to
974.Xr chdir 2
975to the following directories in order and using the first match:
976.Bl -enum
977.It
978.Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
979.Pp
980(Only if
981.Ql Ev MAKEOBJDIRPREFIX
982is set in the environment or on the command line.)
983.It
984.Ev ${MAKEOBJDIR}
985.Pp
986(Only if
987.Ql Ev MAKEOBJDIR
988is set in the environment or on the command line.)
989.It
990.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
991.It
992.Ev ${.CURDIR} Ns Pa /obj
993.It
994.Pa /usr/obj/ Ns Ev ${.CURDIR}
995.It
996.Ev ${.CURDIR}
997.El
998.Pp
999Variable expansion is performed on the value before it's used,
1000so expressions such as
1001.Dl ${.CURDIR:S,^/usr/src,/var/obj,}
1002may be used.
1003This is especially useful with
1004.Ql Ev MAKEOBJDIR .
1005.Pp
1006.Ql Va .OBJDIR
1007may be modified in the makefile via the special target
1008.Ql Ic .OBJDIR .
1009In all cases,
1010.Nm
1011will
1012.Xr chdir 2
1013to the specified directory if it exists, and set
1014.Ql Va .OBJDIR
1015and
1016.Ql Ev PWD
1017to that directory before executing any targets.
1018.
1019.It Va .PARSEDIR
1020A path to the directory of the current
1021.Ql Pa Makefile
1022being parsed.
1023.It Va .PARSEFILE
1024The basename of the current
1025.Ql Pa Makefile
1026being parsed.
1027This variable and
1028.Ql Va .PARSEDIR
1029are both set only while the
1030.Ql Pa Makefiles
1031are being parsed.
1032If you want to retain their current values, assign them to a variable
1033using assignment with expansion:
1034.Pq Ql Cm \&:= .
1035.It Va .PATH
1036A variable that represents the list of directories that
1037.Nm
1038will search for files.
1039The search list should be updated using the target
1040.Ql Va .PATH
1041rather than the variable.
1042.It Ev PWD
1043Alternate path to the current directory.
1044.Nm
1045normally sets
1046.Ql Va .CURDIR
1047to the canonical path given by
1048.Xr getcwd 3 .
1049However, if the environment variable
1050.Ql Ev PWD
1051is set and gives a path to the current directory, then
1052.Nm
1053sets
1054.Ql Va .CURDIR
1055to the value of
1056.Ql Ev PWD
1057instead.
1058This behaviour is disabled if
1059.Ql Ev MAKEOBJDIRPREFIX
1060is set or
1061.Ql Ev MAKEOBJDIR
1062contains a variable transform.
1063.Ql Ev PWD
1064is set to the value of
1065.Ql Va .OBJDIR
1066for all programs which
1067.Nm
1068executes.
1069.It Ev .TARGETS
1070The list of targets explicitly specified on the command line, if any.
1071.It Ev VPATH
1072Colon-separated
1073.Pq Dq \&:
1074lists of directories that
1075.Nm
1076will search for files.
1077The variable is supported for compatibility with old make programs only,
1078use
1079.Ql Va .PATH
1080instead.
1081.El
1082.Ss Variable modifiers
1083Variable expansion may be modified to select or modify each word of the
1084variable (where a
1085.Dq word
1086is white-space delimited sequence of characters).
1087The general format of a variable expansion is as follows:
1088.Pp
1089.Dl ${variable[:modifier[:...]]}
1090.Pp
1091Each modifier begins with a colon,
1092which may be escaped with a backslash
1093.Pq Ql \e .
1094.Pp
1095A set of modifiers can be specified via a variable, as follows:
1096.Pp
1097.Dl modifier_variable=modifier[:...]
1098.Dl ${variable:${modifier_variable}[:...]}
1099.Pp
1100In this case the first modifier in the modifier_variable does not
1101start with a colon, since that must appear in the referencing
1102variable.
1103If any of the modifiers in the modifier_variable contain a dollar sign
1104.Pq Ql $ ,
1105these must be doubled to avoid early expansion.
1106.Pp
1107The supported modifiers are:
1108.Bl -tag -width EEE
1109.It Cm \&:E
1110Replaces each word in the variable with its suffix.
1111.It Cm \&:H
1112Replaces each word in the variable with everything but the last component.
1113.It Cm \&:M Ns Ar pattern
1114Select only those words that match
1115.Ar pattern .
1116The standard shell wildcard characters
1117.Pf ( Ql * ,
1118.Ql \&? ,
1119and
1120.Ql Oo Oc )
1121may
1122be used.
1123The wildcard characters may be escaped with a backslash
1124.Pq Ql \e .
1125As a consequence of the way values are split into words, matched,
1126and then joined, a construct like
1127.Dl ${VAR:M*}
1128will normalise the inter-word spacing, removing all leading and
1129trailing space, and converting multiple consecutive spaces
1130to single spaces.
1131.
1132.It Cm \&:N Ns Ar pattern
1133This is identical to
1134.Ql Cm \&:M ,
1135but selects all words which do not match
1136.Ar pattern .
1137.It Cm \&:O
1138Order every word in variable alphabetically.
1139To sort words in
1140reverse order use the
1141.Ql Cm \&:O:[-1..1]
1142combination of modifiers.
1143.It Cm \&:Ox
1144Randomize words in variable.
1145The results will be different each time you are referring to the
1146modified variable; use the assignment with expansion
1147.Pq Ql Cm \&:=
1148to prevent such behaviour.
1149For example,
1150.Bd -literal -offset indent
1151LIST=			uno due tre quattro
1152RANDOM_LIST=		${LIST:Ox}
1153STATIC_RANDOM_LIST:=	${LIST:Ox}
1154
1155all:
1156	@echo "${RANDOM_LIST}"
1157	@echo "${RANDOM_LIST}"
1158	@echo "${STATIC_RANDOM_LIST}"
1159	@echo "${STATIC_RANDOM_LIST}"
1160.Ed
1161may produce output similar to:
1162.Bd -literal -offset indent
1163quattro due tre uno
1164tre due quattro uno
1165due uno quattro tre
1166due uno quattro tre
1167.Ed
1168.It Cm \&:Q
1169Quotes every shell meta-character in the variable, so that it can be passed
1170safely through recursive invocations of
1171.Nm .
1172.It Cm \&:R
1173Replaces each word in the variable with everything but its suffix.
1174.It Cm \&:gmtime
1175The value is a format string for
1176.Xr strftime 3 ,
1177using the current
1178.Xr gmtime 3 .
1179.It Cm \&:hash
1180Compute a 32bit hash of the value and encode it as hex digits.
1181.It Cm \&:localtime
1182The value is a format string for
1183.Xr strftime 3 ,
1184using the current
1185.Xr localtime 3 .
1186.It Cm \&:tA
1187Attempt to convert variable to an absolute path using
1188.Xr realpath 3 ,
1189if that fails, the value is unchanged.
1190.It Cm \&:tl
1191Converts variable to lower-case letters.
1192.It Cm \&:ts Ns Ar c
1193Words in the variable are normally separated by a space on expansion.
1194This modifier sets the separator to the character
1195.Ar c .
1196If
1197.Ar c
1198is omitted, then no separator is used.
1199The common escapes (including octal numeric codes), work as expected.
1200.It Cm \&:tu
1201Converts variable to upper-case letters.
1202.It Cm \&:tW
1203Causes the value to be treated as a single word
1204(possibly containing embedded white space).
1205See also
1206.Ql Cm \&:[*] .
1207.It Cm \&:tw
1208Causes the value to be treated as a sequence of
1209words delimited by white space.
1210See also
1211.Ql Cm \&:[@] .
1212.Sm off
1213.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1214.Sm on
1215Modify the first occurrence of
1216.Ar old_string
1217in the variable's value, replacing it with
1218.Ar new_string .
1219If a
1220.Ql g
1221is appended to the last slash of the pattern, all occurrences
1222in each word are replaced.
1223If a
1224.Ql 1
1225is appended to the last slash of the pattern, only the first word
1226is affected.
1227If a
1228.Ql W
1229is appended to the last slash of the pattern,
1230then the value is treated as a single word
1231(possibly containing embedded white space).
1232If
1233.Ar old_string
1234begins with a caret
1235.Pq Ql ^ ,
1236.Ar old_string
1237is anchored at the beginning of each word.
1238If
1239.Ar old_string
1240ends with a dollar sign
1241.Pq Ql \&$ ,
1242it is anchored at the end of each word.
1243Inside
1244.Ar new_string ,
1245an ampersand
1246.Pq Ql \*[Am]
1247is replaced by
1248.Ar old_string
1249(without any
1250.Ql ^
1251or
1252.Ql \&$ ) .
1253Any character may be used as a delimiter for the parts of the modifier
1254string.
1255The anchoring, ampersand and delimiter characters may be escaped with a
1256backslash
1257.Pq Ql \e .
1258.Pp
1259Variable expansion occurs in the normal fashion inside both
1260.Ar old_string
1261and
1262.Ar new_string
1263with the single exception that a backslash is used to prevent the expansion
1264of a dollar sign
1265.Pq Ql \&$ ,
1266not a preceding dollar sign as is usual.
1267.Sm off
1268.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1269.Sm on
1270The
1271.Cm \&:C
1272modifier is just like the
1273.Cm \&:S
1274modifier except that the old and new strings, instead of being
1275simple strings, are an extended regular expression (see
1276.Xr regex 3 )
1277string
1278.Ar pattern
1279and an
1280.Xr ed 1 Ns \-style
1281string
1282.Ar replacement .
1283Normally, the first occurrence of the pattern
1284.Ar pattern
1285in each word of the value is substituted with
1286.Ar replacement .
1287The
1288.Ql 1
1289modifier causes the substitution to apply to at most one word; the
1290.Ql g
1291modifier causes the substitution to apply to as many instances of the
1292search pattern
1293.Ar pattern
1294as occur in the word or words it is found in; the
1295.Ql W
1296modifier causes the value to be treated as a single word
1297(possibly containing embedded white space).
1298Note that
1299.Ql 1
1300and
1301.Ql g
1302are orthogonal; the former specifies whether multiple words are
1303potentially affected, the latter whether multiple substitutions can
1304potentially occur within each affected word.
1305.Pp
1306As for the
1307.Cm \&:S
1308modifier, the
1309.Ar pattern
1310and
1311.Ar replacement
1312are subjected to variable expansion before being parsed as
1313regular expressions.
1314.It Cm \&:T
1315Replaces each word in the variable with its last component.
1316.It Cm \&:u
1317Remove adjacent duplicate words (like
1318.Xr uniq 1 ) .
1319.Sm off
1320.It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1321.Sm on
1322If the variable name (not its value), when parsed as a .if conditional
1323expression, evaluates to true, return as its value the
1324.Ar true_string ,
1325otherwise return the
1326.Ar false_string .
1327Since the variable name is used as the expression, \&:\&? must be the
1328first modifier after the variable name itself - which will, of course,
1329usually contain variable expansions.
1330A common error is trying to use expressions like
1331.Dl ${NUMBERS:M42:?match:no}
1332which actually tests defined(NUMBERS),
1333to determine is any words match "42" you need to use something like:
1334.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1335.It Ar :old_string=new_string
1336This is the
1337.At V
1338style variable substitution.
1339It must be the last modifier specified.
1340If
1341.Ar old_string
1342or
1343.Ar new_string
1344do not contain the pattern matching character
1345.Ar %
1346then it is assumed that they are
1347anchored at the end of each word, so only suffixes or entire
1348words may be replaced.
1349Otherwise
1350.Ar %
1351is the substring of
1352.Ar old_string
1353to be replaced in
1354.Ar new_string .
1355.Pp
1356Variable expansion occurs in the normal fashion inside both
1357.Ar old_string
1358and
1359.Ar new_string
1360with the single exception that a backslash is used to prevent the
1361expansion of a dollar sign
1362.Pq Ql \&$ ,
1363not a preceding dollar sign as is usual.
1364.Sm off
1365.It Cm \&:@ Ar temp Cm @ Ar string Cm @
1366.Sm on
1367This is the loop expansion mechanism from the OSF Development
1368Environment (ODE) make.
1369Unlike
1370.Cm \&.for
1371loops expansion occurs at the time of
1372reference.
1373Assign
1374.Ar temp
1375to each word in the variable and evaluate
1376.Ar string .
1377The ODE convention is that
1378.Ar temp
1379should start and end with a period.
1380For example.
1381.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1382.Pp
1383However a single character variable is often more readable:
1384.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1385.It Cm \&:U Ns Ar newval
1386If the variable is undefined
1387.Ar newval
1388is the value.
1389If the variable is defined, the existing value is returned.
1390This is another ODE make feature.
1391It is handy for setting per-target CFLAGS for instance:
1392.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1393If a value is only required if the variable is undefined, use:
1394.Dl ${VAR:D:Unewval}
1395.It Cm \&:D Ns Ar newval
1396If the variable is defined
1397.Ar newval
1398is the value.
1399.It Cm \&:L
1400The name of the variable is the value.
1401.It Cm \&:P
1402The path of the node which has the same name as the variable
1403is the value.
1404If no such node exists or its path is null, then the
1405name of the variable is used.
1406In order for this modifier to work, the name (node) must at least have
1407appeared on the rhs of a dependency.
1408.Sm off
1409.It Cm \&:\&! Ar cmd Cm \&!
1410.Sm on
1411The output of running
1412.Ar cmd
1413is the value.
1414.It Cm \&:sh
1415If the variable is non-empty it is run as a command and the output
1416becomes the new value.
1417.It Cm \&::= Ns Ar str
1418The variable is assigned the value
1419.Ar str
1420after substitution.
1421This modifier and its variations are useful in
1422obscure situations such as wanting to set a variable when shell commands
1423are being parsed.
1424These assignment modifiers always expand to
1425nothing, so if appearing in a rule line by themselves should be
1426preceded with something to keep
1427.Nm
1428happy.
1429.Pp
1430The
1431.Ql Cm \&::
1432helps avoid false matches with the
1433.At V
1434style
1435.Cm \&:=
1436modifier and since substitution always occurs the
1437.Cm \&::=
1438form is vaguely appropriate.
1439.It Cm \&::?= Ns Ar str
1440As for
1441.Cm \&::=
1442but only if the variable does not already have a value.
1443.It Cm \&::+= Ns Ar str
1444Append
1445.Ar str
1446to the variable.
1447.It Cm \&::!= Ns Ar cmd
1448Assign the output of
1449.Ar cmd
1450to the variable.
1451.It Cm \&:\&[ Ns Ar range Ns Cm \&]
1452Selects one or more words from the value,
1453or performs other operations related to the way in which the
1454value is divided into words.
1455.Pp
1456Ordinarily, a value is treated as a sequence of words
1457delimited by white space.
1458Some modifiers suppress this behaviour,
1459causing a value to be treated as a single word
1460(possibly containing embedded white space).
1461An empty value, or a value that consists entirely of white-space,
1462is treated as a single word.
1463For the purposes of the
1464.Ql Cm \&:[]
1465modifier, the words are indexed both forwards using positive integers
1466(where index 1 represents the first word),
1467and backwards using negative integers
1468(where index \-1 represents the last word).
1469.Pp
1470The
1471.Ar range
1472is subjected to variable expansion, and the expanded result is
1473then interpreted as follows:
1474.Bl -tag -width index
1475.\" :[n]
1476.It Ar index
1477Selects a single word from the value.
1478.\" :[start..end]
1479.It Ar start Ns Cm \&.. Ns Ar end
1480Selects all words from
1481.Ar start
1482to
1483.Ar end ,
1484inclusive.
1485For example,
1486.Ql Cm \&:[2..-1]
1487selects all words from the second word to the last word.
1488If
1489.Ar start
1490is greater than
1491.Ar end ,
1492then the words are output in reverse order.
1493For example,
1494.Ql Cm \&:[-1..1]
1495selects all the words from last to first.
1496.\" :[*]
1497.It Cm \&*
1498Causes subsequent modifiers to treat the value as a single word
1499(possibly containing embedded white space).
1500Analogous to the effect of
1501\&"$*\&"
1502in Bourne shell.
1503.\" :[0]
1504.It 0
1505Means the same as
1506.Ql Cm \&:[*] .
1507.\" :[*]
1508.It Cm \&@
1509Causes subsequent modifiers to treat the value as a sequence of words
1510delimited by white space.
1511Analogous to the effect of
1512\&"$@\&"
1513in Bourne shell.
1514.\" :[#]
1515.It Cm \&#
1516Returns the number of words in the value.
1517.El \" :[range]
1518.El
1519.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1520Makefile inclusion, conditional structures and for loops  reminiscent
1521of the C programming language are provided in
1522.Nm .
1523All such structures are identified by a line beginning with a single
1524dot
1525.Pq Ql \&.
1526character.
1527Files are included with either
1528.Cm \&.include Aq Ar file
1529or
1530.Cm \&.include Pf \*q Ar file Ns \*q .
1531Variables between the angle brackets or double quotes are expanded
1532to form the file name.
1533If angle brackets are used, the included makefile is expected to be in
1534the system makefile directory.
1535If double quotes are used, the including makefile's directory and any
1536directories specified using the
1537.Fl I
1538option are searched before the system
1539makefile directory.
1540For compatibility with other versions of
1541.Nm
1542.Ql include file ...
1543is also accepted.
1544If the include statement is written as
1545.Cm .-include
1546or as
1547.Cm .sinclude
1548then errors locating and/or opening include files are ignored.
1549.Pp
1550Conditional expressions are also preceded by a single dot as the first
1551character of a line.
1552The possible conditionals are as follows:
1553.Bl -tag -width Ds
1554.It Ic .error Ar message
1555The message is printed along with the name of the makefile and line number,
1556then
1557.Nm
1558will exit.
1559.It Ic .export Ar variable ...
1560Export the specified global variable.
1561If no variable list is provided, all globals are exported
1562except for internal variables (those that start with
1563.Ql \&. ) .
1564This is not affected by the
1565.Fl X
1566flag, so should be used with caution.
1567For compatibility with other
1568.Nm
1569programs
1570.Ql export variable=value
1571is also accepted.
1572.Pp
1573Appending a variable name to
1574.Va .MAKE.EXPORTED
1575is equivalent to exporting a variable.
1576.It Ic .export-env Ar variable ...
1577The same as
1578.Ql .export ,
1579except that the variable is not appended to
1580.Va .MAKE.EXPORTED .
1581This allows exporting a value to the environment which is different from that
1582used by
1583.Nm
1584internally.
1585.It Ic .info Ar message
1586The message is printed along with the name of the makefile and line number.
1587.It Ic .undef Ar variable
1588Un-define the specified global variable.
1589Only global variables may be un-defined.
1590.It Ic .unexport Ar variable ...
1591The opposite of
1592.Ql .export .
1593The specified global
1594.Va variable
1595will be removed from
1596.Va .MAKE.EXPORTED .
1597If no variable list is provided, all globals are unexported,
1598and
1599.Va .MAKE.EXPORTED
1600deleted.
1601.It Ic .unexport-env
1602Unexport all globals previously exported and
1603clear the environment inherited from the parent.
1604This operation will cause a memory leak of the original environment,
1605so should be used sparingly.
1606Testing for
1607.Va .MAKE.LEVEL
1608being 0, would make sense.
1609Also note that any variables which originated in the parent environment
1610should be explicitly preserved if desired.
1611For example:
1612.Bd -literal -offset indent
1613.Li .if ${.MAKE.LEVEL} == 0
1614PATH := ${PATH}
1615.Li .unexport-env
1616.Li .export PATH
1617.Li .endif
1618.Pp
1619.Ed
1620Would result in an environment containing only
1621.Ql Ev PATH ,
1622which is the minimal useful environment.
1623Actually
1624.Ql Ev .MAKE.LEVEL
1625will also be pushed into the new environment.
1626.It Ic .warning Ar message
1627The message prefixed by
1628.Ql Pa warning:
1629is printed along with the name of the makefile and line number.
1630.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1631Test the value of an expression.
1632.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1633Test the value of a variable.
1634.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1635Test the value of a variable.
1636.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1637Test the target being built.
1638.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1639Test the target being built.
1640.It Ic .else
1641Reverse the sense of the last conditional.
1642.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1643A combination of
1644.Ql Ic .else
1645followed by
1646.Ql Ic .if .
1647.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1648A combination of
1649.Ql Ic .else
1650followed by
1651.Ql Ic .ifdef .
1652.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1653A combination of
1654.Ql Ic .else
1655followed by
1656.Ql Ic .ifndef .
1657.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1658A combination of
1659.Ql Ic .else
1660followed by
1661.Ql Ic .ifmake .
1662.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1663A combination of
1664.Ql Ic .else
1665followed by
1666.Ql Ic .ifnmake .
1667.It Ic .endif
1668End the body of the conditional.
1669.El
1670.Pp
1671The
1672.Ar operator
1673may be any one of the following:
1674.Bl -tag -width "Cm XX"
1675.It Cm \&|\&|
1676Logical OR.
1677.It Cm \&\*[Am]\*[Am]
1678Logical
1679.Tn AND ;
1680of higher precedence than
1681.Dq \&|\&| .
1682.El
1683.Pp
1684As in C,
1685.Nm
1686will only evaluate a conditional as far as is necessary to determine
1687its value.
1688Parentheses may be used to change the order of evaluation.
1689The boolean operator
1690.Ql Ic \&!
1691may be used to logically negate an entire
1692conditional.
1693It is of higher precedence than
1694.Ql Ic \&\*[Am]\*[Am] .
1695.Pp
1696The value of
1697.Ar expression
1698may be any of the following:
1699.Bl -tag -width defined
1700.It Ic defined
1701Takes a variable name as an argument and evaluates to true if the variable
1702has been defined.
1703.It Ic make
1704Takes a target name as an argument and evaluates to true if the target
1705was specified as part of
1706.Nm Ns 's
1707command line or was declared the default target (either implicitly or
1708explicitly, see
1709.Va .MAIN )
1710before the line containing the conditional.
1711.It Ic empty
1712Takes a variable, with possible modifiers, and evaluates to true if
1713the expansion of the variable would result in an empty string.
1714.It Ic exists
1715Takes a file name as an argument and evaluates to true if the file exists.
1716The file is searched for on the system search path (see
1717.Va .PATH ) .
1718.It Ic target
1719Takes a target name as an argument and evaluates to true if the target
1720has been defined.
1721.It Ic commands
1722Takes a target name as an argument and evaluates to true if the target
1723has been defined and has commands associated with it.
1724.El
1725.Pp
1726.Ar Expression
1727may also be an arithmetic or string comparison.
1728Variable expansion is
1729performed on both sides of the comparison, after which the integral
1730values are compared.
1731A value is interpreted as hexadecimal if it is
1732preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1733The standard C relational operators are all supported.
1734If after
1735variable expansion, either the left or right hand side of a
1736.Ql Ic ==
1737or
1738.Ql Ic "!="
1739operator is not an integral value, then
1740string comparison is performed between the expanded
1741variables.
1742If no relational operator is given, it is assumed that the expanded
1743variable is being compared against 0 or an empty string in the case
1744of a string comparison.
1745.Pp
1746When
1747.Nm
1748is evaluating one of these conditional expressions, and it encounters
1749a (white-space separated) word it doesn't recognize, either the
1750.Dq make
1751or
1752.Dq defined
1753expression is applied to it, depending on the form of the conditional.
1754If the form is
1755.Ql Ic .ifdef ,
1756.Ql Ic .ifndef ,
1757or
1758.Ql Ic .if
1759the
1760.Dq defined
1761expression is applied.
1762Similarly, if the form is
1763.Ql Ic .ifmake
1764or
1765.Ql Ic .ifnmake , the
1766.Dq make
1767expression is applied.
1768.Pp
1769If the conditional evaluates to true the parsing of the makefile continues
1770as before.
1771If it evaluates to false, the following lines are skipped.
1772In both cases this continues until a
1773.Ql Ic .else
1774or
1775.Ql Ic .endif
1776is found.
1777.Pp
1778For loops are typically used to apply a set of rules to a list of files.
1779The syntax of a for loop is:
1780.Pp
1781.Bl -tag -compact -width Ds
1782.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1783.It Aq make-rules
1784.It Ic \&.endfor
1785.El
1786.Pp
1787After the for
1788.Ic expression
1789is evaluated, it is split into words.
1790On each iteration of the loop, one word is taken and assigned to each
1791.Ic variable ,
1792in order, and these
1793.Ic variables
1794are substituted into the
1795.Ic make-rules
1796inside the body of the for loop.
1797The number of words must come out even; that is, if there are three
1798iteration variables, the number of words provided must be a multiple
1799of three.
1800.Sh COMMENTS
1801Comments begin with a hash
1802.Pq Ql \&#
1803character, anywhere but in a shell
1804command line, and continue to the end of an unescaped new line.
1805.Sh SPECIAL SOURCES (ATTRIBUTES)
1806.Bl -tag -width .IGNOREx
1807.It Ic .EXEC
1808Target is never out of date, but always execute commands anyway.
1809.It Ic .IGNORE
1810Ignore any errors from the commands associated with this target, exactly
1811as if they all were preceded by a dash
1812.Pq Ql \- .
1813.\" .It Ic .INVISIBLE
1814.\" XXX
1815.\" .It Ic .JOIN
1816.\" XXX
1817.It Ic .MADE
1818Mark all sources of this target as being up-to-date.
1819.It Ic .MAKE
1820Execute the commands associated with this target even if the
1821.Fl n
1822or
1823.Fl t
1824options were specified.
1825Normally used to mark recursive
1826.Nm Ns s .
1827.It Ic .META
1828Create a meta file for the target, even if it is flagged as
1829.Ic .PHONY ,
1830.Ic .MAKE ,
1831or
1832.Ic .SPECIAL .
1833Usage in conjunction with
1834.Ic .MAKE
1835is the most likely case.
1836In "meta" mode, the target is out-of-date if the meta file is missing.
1837.It Ic .NOMETA
1838Do not create a meta file for the target.
1839Meta files are also not created for
1840.Ic .PHONY ,
1841.Ic .MAKE ,
1842or
1843.Ic .SPECIAL
1844targets.
1845.It Ic .NOMETA_CMP
1846Ignore differences in commands when deciding if target is out of date.
1847This is useful if the command contains a value which always changes.
1848If the number of commands change, though, the target will still be out of date.
1849The same effect applies to any command line that uses the variable
1850.Va .OODATE ,
1851which can be used for that purpose even when not otherwise needed or desired:
1852.Bd -literal -offset indent
1853
1854skip-compare-for-some:
1855	@echo this will be compared
1856	@echo this will not ${.OODATE:M.NOMETA_CMP}
1857	@echo this will also be compared
1858
1859.Ed
1860The
1861.Cm \&:M
1862pattern suppresses any expansion of the unwanted variable.
1863.It Ic .NOPATH
1864Do not search for the target in the directories specified by
1865.Ic .PATH .
1866.It Ic .NOTMAIN
1867Normally
1868.Nm
1869selects the first target it encounters as the default target to be built
1870if no target was specified.
1871This source prevents this target from being selected.
1872.It Ic .OPTIONAL
1873If a target is marked with this attribute and
1874.Nm
1875can't figure out how to create it, it will ignore this fact and assume
1876the file isn't needed or already exists.
1877.It Ic .PHONY
1878The target does not
1879correspond to an actual file; it is always considered to be out of date,
1880and will not be created with the
1881.Fl t
1882option.
1883Suffix-transformation rules are not applied to
1884.Ic .PHONY
1885targets.
1886.It Ic .PRECIOUS
1887When
1888.Nm
1889is interrupted, it normally removes any partially made targets.
1890This source prevents the target from being removed.
1891.It Ic .RECURSIVE
1892Synonym for
1893.Ic .MAKE .
1894.It Ic .SILENT
1895Do not echo any of the commands associated with this target, exactly
1896as if they all were preceded by an at sign
1897.Pq Ql @ .
1898.It Ic .USE
1899Turn the target into
1900.Nm Ns 's
1901version of a macro.
1902When the target is used as a source for another target, the other target
1903acquires the commands, sources, and attributes (except for
1904.Ic .USE )
1905of the
1906source.
1907If the target already has commands, the
1908.Ic .USE
1909target's commands are appended
1910to them.
1911.It Ic .USEBEFORE
1912Exactly like
1913.Ic .USE ,
1914but prepend the
1915.Ic .USEBEFORE
1916target commands to the target.
1917.It Ic .WAIT
1918If
1919.Ic .WAIT
1920appears in a dependency line, the sources that precede it are
1921made before the sources that succeed it in the line.
1922Since the dependents of files are not made until the file itself
1923could be made, this also stops the dependents being built unless they
1924are needed for another branch of the dependency tree.
1925So given:
1926.Bd -literal
1927x: a .WAIT b
1928	echo x
1929a:
1930	echo a
1931b: b1
1932	echo b
1933b1:
1934	echo b1
1935
1936.Ed
1937the output is always
1938.Ql a ,
1939.Ql b1 ,
1940.Ql b ,
1941.Ql x .
1942.br
1943The ordering imposed by
1944.Ic .WAIT
1945is only relevant for parallel makes.
1946.El
1947.Sh SPECIAL TARGETS
1948Special targets may not be included with other targets, i.e. they must be
1949the only target specified.
1950.Bl -tag -width .BEGINx
1951.It Ic .BEGIN
1952Any command lines attached to this target are executed before anything
1953else is done.
1954.It Ic .DEFAULT
1955This is sort of a
1956.Ic .USE
1957rule for any target (that was used only as a
1958source) that
1959.Nm
1960can't figure out any other way to create.
1961Only the shell script is used.
1962The
1963.Ic .IMPSRC
1964variable of a target that inherits
1965.Ic .DEFAULT Ns 's
1966commands is set
1967to the target's own name.
1968.It Ic .END
1969Any command lines attached to this target are executed after everything
1970else is done.
1971.It Ic .ERROR
1972Any command lines attached to this target are executed when another target fails.
1973The
1974.Ic .ERROR_TARGET
1975variable is set to the target that failed.
1976See also
1977.Ic MAKE_PRINT_VAR_ON_ERROR .
1978.It Ic .IGNORE
1979Mark each of the sources with the
1980.Ic .IGNORE
1981attribute.
1982If no sources are specified, this is the equivalent of specifying the
1983.Fl i
1984option.
1985.It Ic .INTERRUPT
1986If
1987.Nm
1988is interrupted, the commands for this target will be executed.
1989.It Ic .MAIN
1990If no target is specified when
1991.Nm
1992is invoked, this target will be built.
1993.It Ic .MAKEFLAGS
1994This target provides a way to specify flags for
1995.Nm
1996when the makefile is used.
1997The flags are as if typed to the shell, though the
1998.Fl f
1999option will have
2000no effect.
2001.\" XXX: NOT YET!!!!
2002.\" .It Ic .NOTPARALLEL
2003.\" The named targets are executed in non parallel mode.
2004.\" If no targets are
2005.\" specified, then all targets are executed in non parallel mode.
2006.It Ic .NOPATH
2007Apply the
2008.Ic .NOPATH
2009attribute to any specified sources.
2010.It Ic .NOTPARALLEL
2011Disable parallel mode.
2012.It Ic .NO_PARALLEL
2013Synonym for
2014.Ic .NOTPARALLEL ,
2015for compatibility with other pmake variants.
2016.It Ic .OBJDIR
2017The source is a new value for
2018.Ql Va .OBJDIR .
2019If it exists,
2020.Nm
2021will
2022.Xr chdir 2
2023to it and update the value of
2024.Ql Va .OBJDIR .
2025.It Ic .ORDER
2026The named targets are made in sequence.
2027This ordering does not add targets to the list of targets to be made.
2028Since the dependents of a target do not get built until the target itself
2029could be built, unless
2030.Ql a
2031is built by another part of the dependency graph,
2032the following is a dependency loop:
2033.Bd -literal
2034\&.ORDER: b a
2035b: a
2036.Ed
2037.Pp
2038The ordering imposed by
2039.Ic .ORDER
2040is only relevant for parallel makes.
2041.\" XXX: NOT YET!!!!
2042.\" .It Ic .PARALLEL
2043.\" The named targets are executed in parallel mode.
2044.\" If no targets are
2045.\" specified, then all targets are executed in parallel mode.
2046.It Ic .PATH
2047The sources are directories which are to be searched for files not
2048found in the current directory.
2049If no sources are specified, any previously specified directories are
2050deleted.
2051If the source is the special
2052.Ic .DOTLAST
2053target, then the current working
2054directory is searched last.
2055.It Ic .PATH. Ns Va suffix
2056Like
2057.Ic .PATH
2058but applies only to files with a particular suffix.
2059The suffix must have been previously declared with
2060.Ic .SUFFIXES .
2061.It Ic .PHONY
2062Apply the
2063.Ic .PHONY
2064attribute to any specified sources.
2065.It Ic .PRECIOUS
2066Apply the
2067.Ic .PRECIOUS
2068attribute to any specified sources.
2069If no sources are specified, the
2070.Ic .PRECIOUS
2071attribute is applied to every
2072target in the file.
2073.It Ic .SHELL
2074Sets the shell that
2075.Nm
2076will use to execute commands.
2077The sources are a set of
2078.Ar field=value
2079pairs.
2080.Bl -tag -width hasErrCtls
2081.It Ar name
2082This is the minimal specification, used to select one of the builtin
2083shell specs;
2084.Ar sh ,
2085.Ar ksh ,
2086and
2087.Ar csh .
2088.It Ar path
2089Specifies the path to the shell.
2090.It Ar hasErrCtl
2091Indicates whether the shell supports exit on error.
2092.It Ar check
2093The command to turn on error checking.
2094.It Ar ignore
2095The command to disable error checking.
2096.It Ar echo
2097The command to turn on echoing of commands executed.
2098.It Ar quiet
2099The command to turn off echoing of commands executed.
2100.It Ar filter
2101The output to filter after issuing the
2102.Ar quiet
2103command.
2104It is typically identical to
2105.Ar quiet .
2106.It Ar errFlag
2107The flag to pass the shell to enable error checking.
2108.It Ar echoFlag
2109The flag to pass the shell to enable command echoing.
2110.It Ar newline
2111The string literal to pass the shell that results in a single newline
2112character when used outside of any quoting characters.
2113.El
2114Example:
2115.Bd -literal
2116\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2117	check="set \-e" ignore="set +e" \e
2118	echo="set \-v" quiet="set +v" filter="set +v" \e
2119	echoFlag=v errFlag=e newline="'\en'"
2120.Ed
2121.It Ic .SILENT
2122Apply the
2123.Ic .SILENT
2124attribute to any specified sources.
2125If no sources are specified, the
2126.Ic .SILENT
2127attribute is applied to every
2128command in the file.
2129.It Ic .STALE
2130This target gets run when a dependency file contains stale entries, having
2131.Va .ALLSRC
2132set to the name of that dependency file.
2133.It Ic .SUFFIXES
2134Each source specifies a suffix to
2135.Nm .
2136If no sources are specified, any previously specified suffixes are deleted.
2137It allows the creation of suffix-transformation rules.
2138.Pp
2139Example:
2140.Bd -literal
2141\&.SUFFIXES: .o
2142\&.c.o:
2143	cc \-o ${.TARGET} \-c ${.IMPSRC}
2144.Ed
2145.El
2146.Sh ENVIRONMENT
2147.Nm
2148uses the following environment variables, if they exist:
2149.Ev MACHINE ,
2150.Ev MACHINE_ARCH ,
2151.Ev MAKE ,
2152.Ev MAKEFLAGS ,
2153.Ev MAKEOBJDIR ,
2154.Ev MAKEOBJDIRPREFIX ,
2155.Ev MAKESYSPATH ,
2156.Ev PWD ,
2157and
2158.Ev TMPDIR .
2159.Pp
2160.Ev MAKEOBJDIRPREFIX
2161and
2162.Ev MAKEOBJDIR
2163may only be set in the environment or on the command line to
2164.Nm
2165and not as makefile variables;
2166see the description of
2167.Ql Va .OBJDIR
2168for more details.
2169.Sh FILES
2170.Bl -tag -width /usr/share/mk -compact
2171.It .depend
2172list of dependencies
2173.It Makefile
2174list of dependencies
2175.It makefile
2176list of dependencies
2177.It sys.mk
2178system makefile
2179.It /usr/share/mk
2180system makefile directory
2181.El
2182.Sh COMPATIBILITY
2183The basic make syntax is compatible between different versions of make;
2184however the special variables, variable modifiers and conditionals are not.
2185.Ss Older versions
2186An incomplete list of changes in older versions of
2187.Nm :
2188.Pp
2189The way that .for loop variables are substituted changed after
2190.Nx 5.0
2191so that they still appear to be variable expansions.
2192In particular this stops them being treated as syntax, and removes some
2193obscure problems using them in .if statements.
2194.Pp
2195The way that parallel makes are scheduled changed in
2196.Nx 4.0
2197so that .ORDER and .WAIT apply recursively to the dependent nodes.
2198The algorithms used may change again in the future.
2199.Ss Other make dialects
2200Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
2201support most of the features of
2202.Nm
2203as described in this manual.
2204Most notably:
2205.Bl -bullet -offset indent
2206.It
2207The
2208.Ic .WAIT
2209and
2210.Ic .ORDER
2211declarations and most functionality pertaining to parallelization.
2212(GNU make supports parallelization but lacks these features needed to
2213control it effectively.)
2214.It
2215Directives, including for loops and conditionals and most of the
2216forms of include files.
2217(GNU make has its own incompatible and less powerful syntax for
2218conditionals.)
2219.It
2220All built-in variables that begin with a dot.
2221.It
2222Most of the special sources and targets that begin with a dot,
2223with the notable exception of
2224.Ic .PHONY ,
2225.Ic .PRECIOUS ,
2226and
2227.Ic .SUFFIXES .
2228.It
2229Variable modifiers, except for the
2230.Dl :old=new
2231string substitution, which does not portably support globbing with
2232.Ql %
2233and historically only works on declared suffixes.
2234.It
2235The
2236.Ic $>
2237variable even in its short form; most makes support this functionality
2238but its name varies.
2239.El
2240.Pp
2241Some features are somewhat more portable, such as assignment with
2242.Ic += ,
2243.Ic ?= ,
2244and
2245.Ic != .
2246The
2247.Ic .PATH
2248functionality is based on an older feature
2249.Ic VPATH
2250found in GNU make and many versions of SVR4 make; however,
2251historically its behavior is too ill-defined (and too buggy) to rely
2252upon.
2253.Pp
2254The
2255.Ic $@
2256and
2257.Ic $<
2258variables are more or less universally portable, as is the
2259.Ic $(MAKE)
2260variable.
2261Basic use of suffix rules (for files only in the current directory,
2262not trying to chain transformations together, etc.) is also reasonably
2263portable.
2264.Sh SEE ALSO
2265.Xr mkdep 1
2266.Sh HISTORY
2267A
2268.Nm
2269command appeared in
2270.At v7 .
2271This
2272.Nm
2273implementation is based on Adam De Boor's pmake program which was written
2274for Sprite at Berkeley.
2275It was designed to be a parallel distributed make running jobs on different
2276machines using a daemon called
2277.Dq customs .
2278.Pp
2279Historically the target/dependency
2280.Dq FRC
2281has been used to FoRCe rebuilding (since the target/dependency
2282does not exist... unless someone creates an
2283.Dq FRC
2284file).
2285.Sh BUGS
2286The
2287.Nm
2288syntax is difficult to parse without actually acting of the data.
2289For instance finding the end of a variable use should involve scanning each
2290the modifiers using the correct terminator for each field.
2291In many places
2292.Nm
2293just counts {} and () in order to find the end of a variable expansion.
2294.Pp
2295There is no way of escaping a space character in a filename.
2296