xref: /freebsd/contrib/bmake/make.1 (revision a0e793cbf1951d07fc47a0d9ea389d7dacba5213)
1.\"	$NetBSD: make.1,v 1.230 2014/02/15 18:55:30 sjg Exp $
2.\"
3.\" Copyright (c) 1990, 1993
4.\"	The Regents of the University of California.  All rights reserved.
5.\"
6.\" Redistribution and use in source and binary forms, with or without
7.\" modification, are permitted provided that the following conditions
8.\" are met:
9.\" 1. Redistributions of source code must retain the above copyright
10.\"    notice, this list of conditions and the following disclaimer.
11.\" 2. Redistributions in binary form must reproduce the above copyright
12.\"    notice, this list of conditions and the following disclaimer in the
13.\"    documentation and/or other materials provided with the distribution.
14.\" 3. Neither the name of the University nor the names of its contributors
15.\"    may be used to endorse or promote products derived from this software
16.\"    without specific prior written permission.
17.\"
18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28.\" SUCH DAMAGE.
29.\"
30.\"	from: @(#)make.1	8.4 (Berkeley) 3/19/94
31.\"
32.Dd February 14, 2014
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 w
213Print entering and leaving directory messages, pre and post processing.
214.It Ar x
215Run shell commands with
216.Fl x
217so the actual commands are printed as they are executed.
218.El
219.It Fl e
220Specify that environment variables override macro assignments within
221makefiles.
222.It Fl f Ar makefile
223Specify a makefile to read instead of the default
224.Ql Pa makefile .
225If
226.Ar makefile
227is
228.Ql Fl ,
229standard input is read.
230Multiple makefiles may be specified, and are read in the order specified.
231.It Fl I Ar directory
232Specify a directory in which to search for makefiles and included makefiles.
233The system makefile directory (or directories, see the
234.Fl m
235option) is automatically included as part of this list.
236.It Fl i
237Ignore non-zero exit of shell commands in the makefile.
238Equivalent to specifying
239.Ql Fl
240before each command line in the makefile.
241.It Fl J Ar private
242This option should
243.Em not
244be specified by the user.
245.Pp
246When the
247.Ar j
248option is in use in a recursive build, this option is passed by a make
249to child makes to allow all the make processes in the build to
250cooperate to avoid overloading the system.
251.It Fl j Ar max_jobs
252Specify the maximum number of jobs that
253.Nm
254may have running at any one time.
255The value is saved in
256.Va .MAKE.JOBS .
257Turns compatibility mode off, unless the
258.Ar B
259flag is also specified.
260When compatibility mode is off, all commands associated with a
261target are executed in a single shell invocation as opposed to the
262traditional one shell invocation per line.
263This can break traditional scripts which change directories on each
264command invocation and then expect to start with a fresh environment
265on the next line.
266It is more efficient to correct the scripts rather than turn backwards
267compatibility on.
268.It Fl k
269Continue processing after errors are encountered, but only on those targets
270that do not depend on the target whose creation caused the error.
271.It Fl m Ar directory
272Specify a directory in which to search for sys.mk and makefiles included
273via the
274.Ao Ar file Ac Ns -style
275include statement.
276The
277.Fl m
278option can be used multiple times to form a search path.
279This path will override the default system include path: /usr/share/mk.
280Furthermore the system include path will be appended to the search path used
281for
282.Qo Ar file Qc Ns -style
283include statements (see the
284.Fl I
285option).
286.Pp
287If a file or directory name in the
288.Fl m
289argument (or the
290.Ev MAKESYSPATH
291environment variable) starts with the string
292.Qq \&.../
293then
294.Nm
295will search for the specified file or directory named in the remaining part
296of the argument string.
297The search starts with the current directory of
298the Makefile and then works upward towards the root of the filesystem.
299If the search is successful, then the resulting directory replaces the
300.Qq \&.../
301specification in the
302.Fl m
303argument.
304If used, this feature allows
305.Nm
306to easily search in the current source tree for customized sys.mk files
307(e.g., by using
308.Qq \&.../mk/sys.mk
309as an argument).
310.It Fl n
311Display the commands that would have been executed, but do not
312actually execute them unless the target depends on the .MAKE special
313source (see below).
314.It Fl N
315Display the commands which would have been executed, but do not
316actually execute any of them; useful for debugging top-level makefiles
317without descending into subdirectories.
318.It Fl q
319Do not execute any commands, but exit 0 if the specified targets are
320up-to-date and 1, otherwise.
321.It Fl r
322Do not use the built-in rules specified in the system makefile.
323.It Fl s
324Do not echo any commands as they are executed.
325Equivalent to specifying
326.Ql Ic @
327before each command line in the makefile.
328.It Fl T Ar tracefile
329When used with the
330.Fl j
331flag,
332append a trace record to
333.Ar tracefile
334for each job started and completed.
335.It Fl t
336Rather than re-building a target as specified in the makefile, create it
337or update its modification time to make it appear up-to-date.
338.It Fl V Ar variable
339Print
340.Nm Ns 's
341idea of the value of
342.Ar variable ,
343in the global context.
344Do not build any targets.
345Multiple instances of this option may be specified;
346the variables will be printed one per line,
347with a blank line for each null or undefined variable.
348If
349.Ar variable
350contains a
351.Ql \&$
352then the value will be expanded before printing.
353.It Fl W
354Treat any warnings during makefile parsing as errors.
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 a series of shell commands, normally
445used to create the target.
446Each of the commands in this script
447.Em must
448be preceded by a tab.
449While any target may appear on a dependency line, only one of these
450dependencies may be followed by a creation script, unless the
451.Ql Ic \&::
452operator is used.
453.Pp
454If the first characters of the command line are any combination of
455.Ql Ic @ ,
456.Ql Ic + ,
457or
458.Ql Ic \- ,
459the command is treated specially.
460A
461.Ql Ic @
462causes the command not to be echoed before it is executed.
463A
464.Ql Ic +
465causes the command to be executed even when
466.Fl n
467is given.
468This is similar to the effect of the .MAKE special source,
469except that the effect can be limited to a single line of a script.
470A
471.Ql Ic \-
472causes any non-zero exit status of the command line to be ignored.
473.Pp
474When
475.Nm
476is run in jobs mode with
477.Fl j Ar max_jobs ,
478the entire script for the target is fed to a
479single instance of the shell.
480.Pp
481In compatibility (non-jobs) mode, each command is run in a separate process.
482If the command contains any shell meta characters
483.Pq Ql #=|^(){};&<>*?[]:$`\e\en
484it will be passed to the shell, otherwise
485.Nm
486will attempt direct execution.
487.Pp
488Since
489.Nm
490will
491.Xr chdir 2
492to
493.Ql Va .OBJDIR
494before executing any targets, each child process
495starts with that as its current working directory.
496.Pp
497Makefiles should be written so that the mode of
498.Nm
499operation does not change their behavior.
500For example, any command which needs to use
501.Dq cd
502or
503.Dq chdir ,
504without side-effect should be put in parenthesis:
505.Bd -literal -offset indent
506
507avoid-chdir-side-effects:
508	@echo Building $@ in `pwd`
509	@(cd ${.CURDIR} && ${.MAKE} $@)
510	@echo Back in `pwd`
511
512ensure-one-shell-regardless-of-mode:
513	@echo Building $@ in `pwd`; \\
514	(cd ${.CURDIR} && ${.MAKE} $@); \\
515	echo Back in `pwd`
516.Ed
517.Sh VARIABLE ASSIGNMENTS
518Variables in make are much like variables in the shell, and, by tradition,
519consist of all upper-case letters.
520.Ss Variable assignment modifiers
521The five operators that can be used to assign values to variables are as
522follows:
523.Bl -tag -width Ds
524.It Ic \&=
525Assign the value to the variable.
526Any previous value is overridden.
527.It Ic \&+=
528Append the value to the current value of the variable.
529.It Ic \&?=
530Assign the value to the variable if it is not already defined.
531.It Ic \&:=
532Assign with expansion, i.e. expand the value before assigning it
533to the variable.
534Normally, expansion is not done until the variable is referenced.
535.Em NOTE :
536References to undefined variables are
537.Em not
538expanded.
539This can cause problems when variable modifiers are used.
540.It Ic \&!=
541Expand the value and pass it to the shell for execution and assign
542the result to the variable.
543Any newlines in the result are replaced with spaces.
544.El
545.Pp
546Any white-space before the assigned
547.Ar value
548is removed; if the value is being appended, a single space is inserted
549between the previous contents of the variable and the appended value.
550.Pp
551Variables are expanded by surrounding the variable name with either
552curly braces
553.Pq Ql {}
554or parentheses
555.Pq Ql ()
556and preceding it with
557a dollar sign
558.Pq Ql \&$ .
559If the variable name contains only a single letter, the surrounding
560braces or parentheses are not required.
561This shorter form is not recommended.
562.Pp
563If the variable name contains a dollar, then the name itself is expanded first.
564This allows almost arbitrary variable names, however names containing dollar,
565braces, parenthesis, or whitespace are really best avoided!
566.Pp
567If the result of expanding a variable contains a dollar sign
568.Pq Ql \&$
569the string is expanded again.
570.Pp
571Variable substitution occurs at three distinct times, depending on where
572the variable is being used.
573.Bl -enum
574.It
575Variables in dependency lines are expanded as the line is read.
576.It
577Variables in shell commands are expanded when the shell command is
578executed.
579.It
580.Dq .for
581loop index variables are expanded on each loop iteration.
582Note that other variables are not expanded inside loops so
583the following example code:
584.Bd -literal -offset indent
585
586.Dv .for i in 1 2 3
587a+=     ${i}
588j=      ${i}
589b+=     ${j}
590.Dv .endfor
591
592all:
593	@echo ${a}
594	@echo ${b}
595
596.Ed
597will print:
598.Bd -literal -offset indent
5991 2 3
6003 3 3
601
602.Ed
603Because while ${a} contains
604.Dq 1 2 3
605after the loop is executed, ${b}
606contains
607.Dq ${j} ${j} ${j}
608which expands to
609.Dq 3 3 3
610since after the loop completes ${j} contains
611.Dq 3 .
612.El
613.Ss Variable classes
614The four different classes of variables (in order of increasing precedence)
615are:
616.Bl -tag -width Ds
617.It Environment variables
618Variables defined as part of
619.Nm Ns 's
620environment.
621.It Global variables
622Variables defined in the makefile or in included makefiles.
623.It Command line variables
624Variables defined as part of the command line.
625.It Local variables
626Variables that are defined specific to a certain target.
627The seven local variables are as follows:
628.Bl -tag -width ".ARCHIVE"
629.It Va .ALLSRC
630The list of all sources for this target; also known as
631.Ql Va \&\*[Gt] .
632.It Va .ARCHIVE
633The name of the archive file.
634.It Va .IMPSRC
635In suffix-transformation rules, the name/path of the source from which the
636target is to be transformed (the
637.Dq implied
638source); also known as
639.Ql Va \&\*[Lt] .
640It is not defined in explicit rules.
641.It Va .MEMBER
642The name of the archive member.
643.It Va .OODATE
644The list of sources for this target that were deemed out-of-date; also
645known as
646.Ql Va \&? .
647.It Va .PREFIX
648The file prefix of the target, containing only the file portion, no suffix
649or preceding directory components; also known as
650.Ql Va * .
651.It Va .TARGET
652The name of the target; also known as
653.Ql Va @ .
654.El
655.Pp
656The shorter forms
657.Ql Va @ ,
658.Ql Va \&? ,
659.Ql Va \&\*[Lt] ,
660.Ql Va \&\*[Gt] ,
661and
662.Ql Va *
663are permitted for backward
664compatibility with historical makefiles and are not recommended.
665The six variables
666.Ql Va "@F" ,
667.Ql Va "@D" ,
668.Ql Va "\*[Lt]F" ,
669.Ql Va "\*[Lt]D" ,
670.Ql Va "*F" ,
671and
672.Ql Va "*D"
673are permitted for compatibility with
674.At V
675makefiles and are not recommended.
676.Pp
677Four of the local variables may be used in sources on dependency lines
678because they expand to the proper value for each target on the line.
679These variables are
680.Ql Va .TARGET ,
681.Ql Va .PREFIX ,
682.Ql Va .ARCHIVE ,
683and
684.Ql Va .MEMBER .
685.El
686.Ss Additional built-in variables
687In addition,
688.Nm
689sets or knows about the following variables:
690.Bl -tag -width .MAKEOVERRIDES
691.It Va \&$
692A single dollar sign
693.Ql \&$ ,
694i.e.
695.Ql \&$$
696expands to a single dollar
697sign.
698.It Va .ALLTARGETS
699The list of all targets encountered in the Makefile.
700If evaluated during
701Makefile parsing, lists only those targets encountered thus far.
702.It Va .CURDIR
703A path to the directory where
704.Nm
705was executed.
706Refer to the description of
707.Ql Ev PWD
708for more details.
709.It Va .INCLUDEDFROMDIR
710The directory of the file this Makefile was included from.
711.It Va .INCLUDEDFROMFILE
712The filename of the file this Makefile was included from.
713.It Ev MAKE
714The name that
715.Nm
716was executed with
717.Pq Va argv[0] .
718For compatibility
719.Nm
720also sets
721.Va .MAKE
722with the same value.
723The preferred variable to use is the environment variable
724.Ev MAKE
725because it is more compatible with other versions of
726.Nm
727and cannot be confused with the special target with the same name.
728.It Va .MAKE.ALWAYS_PASS_JOB_QUEUE
729Tells
730.Nm
731whether to pass the descriptors of the job token queue
732even if the target is not tagged with
733.Ic .MAKE
734The default is
735.Ql Pa yes
736for backwards compatability with
737.Fx 9.0
738and earlier.
739.It Va .MAKE.DEPENDFILE
740Names the makefile (default
741.Ql Pa .depend )
742from which generated dependencies are read.
743.It Va .MAKE.EXPAND_VARIABLES
744A boolean that controls the default behavior of the
745.Fl V
746option.
747.It Va .MAKE.EXPORTED
748The list of variables exported by
749.Nm .
750.It Va .MAKE.JOBS
751The argument to the
752.Fl j
753option.
754.It Va .MAKE.JOB.PREFIX
755If
756.Nm
757is run with
758.Ar j
759then output for each target is prefixed with a token
760.Ql --- target ---
761the first part of which can be controlled via
762.Va .MAKE.JOB.PREFIX .
763If
764.Va .MAKE.JOB.PREFIX
765is empty, no token is printed.
766.br
767For example:
768.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
769would produce tokens like
770.Ql ---make[1234] target ---
771making it easier to track the degree of parallelism being achieved.
772.It Ev MAKEFLAGS
773The environment variable
774.Ql Ev MAKEFLAGS
775may contain anything that
776may be specified on
777.Nm Ns 's
778command line.
779Anything specified on
780.Nm Ns 's
781command line is appended to the
782.Ql Ev MAKEFLAGS
783variable which is then
784entered into the environment for all programs which
785.Nm
786executes.
787.It Va .MAKE.LEVEL
788The recursion depth of
789.Nm .
790The initial instance of
791.Nm
792will be 0, and an incremented value is put into the environment
793to be seen by the next generation.
794This allows tests like:
795.Li .if ${.MAKE.LEVEL} == 0
796to protect things which should only be evaluated in the initial instance of
797.Nm .
798.It Va .MAKE.MAKEFILE_PREFERENCE
799The ordered list of makefile names
800(default
801.Ql Pa makefile ,
802.Ql Pa Makefile )
803that
804.Nm
805will look for.
806.It Va .MAKE.MAKEFILES
807The list of makefiles read by
808.Nm ,
809which is useful for tracking dependencies.
810Each makefile is recorded only once, regardless of the number of times read.
811.It Va .MAKE.MODE
812Processed after reading all makefiles.
813Can affect the mode that
814.Nm
815runs in.
816It can contain a number of keywords:
817.Bl -hang -width ignore-cmd
818.It Pa compat
819Like
820.Fl B ,
821puts
822.Nm
823into "compat" mode.
824.It Pa meta
825Puts
826.Nm
827into "meta" mode, where meta files are created for each target
828to capture the command run, the output generated and if
829.Xr filemon 4
830is available, the system calls which are of interest to
831.Nm .
832The captured output can be very useful when diagnosing errors.
833.It Pa curdirOk= Ar bf
834Normally
835.Nm
836will not create .meta files in
837.Ql Va .CURDIR .
838This can be overridden by setting
839.Va bf
840to a value which represents True.
841.It Pa env
842For debugging, it can be useful to inlcude the environment
843in the .meta file.
844.It Pa verbose
845If in "meta" mode, print a clue about the target being built.
846This is useful if the build is otherwise running silently.
847The message printed the value of:
848.Va .MAKE.META.PREFIX .
849.It Pa ignore-cmd
850Some makefiles have commands which are simply not stable.
851This keyword causes them to be ignored for
852determining whether a target is out of date in "meta" mode.
853See also
854.Ic .NOMETA_CMP .
855.It Pa silent= Ar bf
856If
857.Va bf
858is True, when a .meta file is created, mark the target
859.Ic .SILENT .
860.El
861.It Va .MAKE.META.BAILIWICK
862In "meta" mode, provides a list of prefixes which
863match the directories controlled by
864.Nm .
865If a file that was generated outside of
866.Va .OBJDIR
867but within said bailiwick is missing,
868the current target is considered out-of-date.
869.It Va .MAKE.META.CREATED
870In "meta" mode, this variable contains a list of all the meta files
871updated.
872If not empty, it can be used to trigger processing of
873.Va .MAKE.META.FILES .
874.It Va .MAKE.META.FILES
875In "meta" mode, this variable contains a list of all the meta files
876used (updated or not).
877This list can be used to process the meta files to extract dependency
878information.
879.It Va .MAKE.META.IGNORE_PATHS
880Provides a list of path prefixes that should be ignored;
881because the contents are expected to change over time.
882The default list includes:
883.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
884.It Va .MAKE.META.PREFIX
885Defines the message printed for each meta file updated in "meta verbose" mode.
886The default value is:
887.Dl Building ${.TARGET:H:tA}/${.TARGET:T}
888.It Va .MAKEOVERRIDES
889This variable is used to record the names of variables assigned to
890on the command line, so that they may be exported as part of
891.Ql Ev MAKEFLAGS .
892This behaviour can be disabled by assigning an empty value to
893.Ql Va .MAKEOVERRIDES
894within a makefile.
895Extra variables can be exported from a makefile
896by appending their names to
897.Ql Va .MAKEOVERRIDES .
898.Ql Ev MAKEFLAGS
899is re-exported whenever
900.Ql Va .MAKEOVERRIDES
901is modified.
902.It Va .MAKE.PATH_FILEMON
903If
904.Nm
905was built with
906.Xr filemon 4
907support, this is set to the path of the device node.
908This allows makefiles to test for this support.
909.It Va .MAKE.PID
910The process-id of
911.Nm .
912.It Va .MAKE.PPID
913The parent process-id of
914.Nm .
915.It Va MAKE_PRINT_VAR_ON_ERROR
916When
917.Nm
918stops due to an error, it prints its name and the value of
919.Ql Va .CURDIR
920as well as the value of any variables named in
921.Ql Va MAKE_PRINT_VAR_ON_ERROR .
922.It Va .newline
923This variable is simply assigned a newline character as its value.
924This allows expansions using the
925.Cm \&:@
926modifier to put a newline between
927iterations of the loop rather than a space.
928For example, the printing of
929.Ql Va MAKE_PRINT_VAR_ON_ERROR
930could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
931.It Va .OBJDIR
932A path to the directory where the targets are built.
933Its value is determined by trying to
934.Xr chdir 2
935to the following directories in order and using the first match:
936.Bl -enum
937.It
938.Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
939.Pp
940(Only if
941.Ql Ev MAKEOBJDIRPREFIX
942is set in the environment or on the command line.)
943.It
944.Ev ${MAKEOBJDIR}
945.Pp
946(Only if
947.Ql Ev MAKEOBJDIR
948is set in the environment or on the command line.)
949.It
950.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
951.It
952.Ev ${.CURDIR} Ns Pa /obj
953.It
954.Pa /usr/obj/ Ns Ev ${.CURDIR}
955.It
956.Ev ${.CURDIR}
957.El
958.Pp
959Variable expansion is performed on the value before it's used,
960so expressions such as
961.Dl ${.CURDIR:S,^/usr/src,/var/obj,}
962may be used.
963This is especially useful with
964.Ql Ev MAKEOBJDIR .
965.Pp
966.Ql Va .OBJDIR
967may be modified in the makefile as a global variable.
968In all cases,
969.Nm
970will
971.Xr chdir 2
972to
973.Ql Va .OBJDIR
974and set
975.Ql Ev PWD
976to that directory before executing any targets.
977.
978.It Va .PARSEDIR
979A path to the directory of the current
980.Ql Pa Makefile
981being parsed.
982.It Va .PARSEFILE
983The basename of the current
984.Ql Pa Makefile
985being parsed.
986This variable and
987.Ql Va .PARSEDIR
988are both set only while the
989.Ql Pa Makefiles
990are being parsed.
991If you want to retain their current values, assign them to a variable
992using assignment with expansion:
993.Pq Ql Cm \&:= .
994.It Va .PATH
995A variable that represents the list of directories that
996.Nm
997will search for files.
998The search list should be updated using the target
999.Ql Va .PATH
1000rather than the variable.
1001.It Ev PWD
1002Alternate path to the current directory.
1003.Nm
1004normally sets
1005.Ql Va .CURDIR
1006to the canonical path given by
1007.Xr getcwd 3 .
1008However, if the environment variable
1009.Ql Ev PWD
1010is set and gives a path to the current directory, then
1011.Nm
1012sets
1013.Ql Va .CURDIR
1014to the value of
1015.Ql Ev PWD
1016instead.
1017This behaviour is disabled if
1018.Ql Ev MAKEOBJDIRPREFIX
1019is set or
1020.Ql Ev MAKEOBJDIR
1021contains a variable transform.
1022.Ql Ev PWD
1023is set to the value of
1024.Ql Va .OBJDIR
1025for all programs which
1026.Nm
1027executes.
1028.It Ev .TARGETS
1029The list of targets explicitly specified on the command line, if any.
1030.It Ev VPATH
1031Colon-separated
1032.Pq Dq \&:
1033lists of directories that
1034.Nm
1035will search for files.
1036The variable is supported for compatibility with old make programs only,
1037use
1038.Ql Va .PATH
1039instead.
1040.El
1041.Ss Variable modifiers
1042Variable expansion may be modified to select or modify each word of the
1043variable (where a
1044.Dq word
1045is white-space delimited sequence of characters).
1046The general format of a variable expansion is as follows:
1047.Pp
1048.Dl ${variable[:modifier[:...]]}
1049.Pp
1050Each modifier begins with a colon,
1051which may be escaped with a backslash
1052.Pq Ql \e .
1053.Pp
1054A set of modifiers can be specified via a variable, as follows:
1055.Pp
1056.Dl modifier_variable=modifier[:...]
1057.Dl ${variable:${modifier_variable}[:...]}
1058.Pp
1059In this case the first modifier in the modifier_variable does not
1060start with a colon, since that must appear in the referencing
1061variable.
1062If any of the modifiers in the modifier_variable contain a dollar sign
1063.Pq Ql $ ,
1064these must be doubled to avoid early expansion.
1065.Pp
1066The supported modifiers are:
1067.Bl -tag -width EEE
1068.It Cm \&:E
1069Replaces each word in the variable with its suffix.
1070.It Cm \&:H
1071Replaces each word in the variable with everything but the last component.
1072.It Cm \&:M Ns Ar pattern
1073Select only those words that match
1074.Ar pattern .
1075The standard shell wildcard characters
1076.Pf ( Ql * ,
1077.Ql \&? ,
1078and
1079.Ql Oo Oc )
1080may
1081be used.
1082The wildcard characters may be escaped with a backslash
1083.Pq Ql \e .
1084As a consequence of the way values are split into words, matched,
1085and then joined, a construct like
1086.Dl ${VAR:M*}
1087will normalise the inter-word spacing, removing all leading and
1088trailing space, and converting multiple consecutive spaces
1089to single spaces.
1090.
1091.It Cm \&:N Ns Ar pattern
1092This is identical to
1093.Ql Cm \&:M ,
1094but selects all words which do not match
1095.Ar pattern .
1096.It Cm \&:O
1097Order every word in variable alphabetically.
1098To sort words in
1099reverse order use the
1100.Ql Cm \&:O:[-1..1]
1101combination of modifiers.
1102.It Cm \&:Ox
1103Randomize words in variable.
1104The results will be different each time you are referring to the
1105modified variable; use the assignment with expansion
1106.Pq Ql Cm \&:=
1107to prevent such behaviour.
1108For example,
1109.Bd -literal -offset indent
1110LIST=			uno due tre quattro
1111RANDOM_LIST=		${LIST:Ox}
1112STATIC_RANDOM_LIST:=	${LIST:Ox}
1113
1114all:
1115	@echo "${RANDOM_LIST}"
1116	@echo "${RANDOM_LIST}"
1117	@echo "${STATIC_RANDOM_LIST}"
1118	@echo "${STATIC_RANDOM_LIST}"
1119.Ed
1120may produce output similar to:
1121.Bd -literal -offset indent
1122quattro due tre uno
1123tre due quattro uno
1124due uno quattro tre
1125due uno quattro tre
1126.Ed
1127.It Cm \&:Q
1128Quotes every shell meta-character in the variable, so that it can be passed
1129safely through recursive invocations of
1130.Nm .
1131.It Cm \&:R
1132Replaces each word in the variable with everything but its suffix.
1133.It Cm \&:gmtime
1134The value is a format string for
1135.Xr strftime 3 ,
1136using the current
1137.Xr gmtime 3 .
1138.It Cm \&:hash
1139Compute a 32bit hash of the value and encode it as hex digits.
1140.It Cm \&:localtime
1141The value is a format string for
1142.Xr strftime 3 ,
1143using the current
1144.Xr localtime 3 .
1145.It Cm \&:tA
1146Attempt to convert variable to an absolute path using
1147.Xr realpath 3 ,
1148if that fails, the value is unchanged.
1149.It Cm \&:tl
1150Converts variable to lower-case letters.
1151.It Cm \&:ts Ns Ar c
1152Words in the variable are normally separated by a space on expansion.
1153This modifier sets the separator to the character
1154.Ar c .
1155If
1156.Ar c
1157is omitted, then no separator is used.
1158The common escapes (including octal numeric codes), work as expected.
1159.It Cm \&:tu
1160Converts variable to upper-case letters.
1161.It Cm \&:tW
1162Causes the value to be treated as a single word
1163(possibly containing embedded white space).
1164See also
1165.Ql Cm \&:[*] .
1166.It Cm \&:tw
1167Causes the value to be treated as a sequence of
1168words delimited by white space.
1169See also
1170.Ql Cm \&:[@] .
1171.Sm off
1172.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1173.Sm on
1174Modify the first occurrence of
1175.Ar old_string
1176in the variable's value, replacing it with
1177.Ar new_string .
1178If a
1179.Ql g
1180is appended to the last slash of the pattern, all occurrences
1181in each word are replaced.
1182If a
1183.Ql 1
1184is appended to the last slash of the pattern, only the first word
1185is affected.
1186If a
1187.Ql W
1188is appended to the last slash of the pattern,
1189then the value is treated as a single word
1190(possibly containing embedded white space).
1191If
1192.Ar old_string
1193begins with a caret
1194.Pq Ql ^ ,
1195.Ar old_string
1196is anchored at the beginning of each word.
1197If
1198.Ar old_string
1199ends with a dollar sign
1200.Pq Ql \&$ ,
1201it is anchored at the end of each word.
1202Inside
1203.Ar new_string ,
1204an ampersand
1205.Pq Ql \*[Am]
1206is replaced by
1207.Ar old_string
1208(without any
1209.Ql ^
1210or
1211.Ql \&$ ) .
1212Any character may be used as a delimiter for the parts of the modifier
1213string.
1214The anchoring, ampersand and delimiter characters may be escaped with a
1215backslash
1216.Pq Ql \e .
1217.Pp
1218Variable expansion occurs in the normal fashion inside both
1219.Ar old_string
1220and
1221.Ar new_string
1222with the single exception that a backslash is used to prevent the expansion
1223of a dollar sign
1224.Pq Ql \&$ ,
1225not a preceding dollar sign as is usual.
1226.Sm off
1227.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1228.Sm on
1229The
1230.Cm \&:C
1231modifier is just like the
1232.Cm \&:S
1233modifier except that the old and new strings, instead of being
1234simple strings, are an extended regular expression (see
1235.Xr regex 3 )
1236string
1237.Ar pattern
1238and an
1239.Xr ed 1 Ns \-style
1240string
1241.Ar replacement .
1242Normally, the first occurrence of the pattern
1243.Ar pattern
1244in each word of the value is substituted with
1245.Ar replacement .
1246The
1247.Ql 1
1248modifier causes the substitution to apply to at most one word; the
1249.Ql g
1250modifier causes the substitution to apply to as many instances of the
1251search pattern
1252.Ar pattern
1253as occur in the word or words it is found in; the
1254.Ql W
1255modifier causes the value to be treated as a single word
1256(possibly containing embedded white space).
1257Note that
1258.Ql 1
1259and
1260.Ql g
1261are orthogonal; the former specifies whether multiple words are
1262potentially affected, the latter whether multiple substitutions can
1263potentially occur within each affected word.
1264.Pp
1265As for the
1266.Cm \&:S
1267modifier, the
1268.Ar pattern
1269and
1270.Ar replacement
1271are subjected to variable expansion before being parsed as
1272regular expressions.
1273.It Cm \&:T
1274Replaces each word in the variable with its last component.
1275.It Cm \&:u
1276Remove adjacent duplicate words (like
1277.Xr uniq 1 ) .
1278.Sm off
1279.It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1280.Sm on
1281If the variable name (not its value), when parsed as a .if conditional
1282expression, evaluates to true, return as its value the
1283.Ar true_string ,
1284otherwise return the
1285.Ar false_string .
1286Since the variable name is used as the expression, \&:\&? must be the
1287first modifier after the variable name itself - which will, of course,
1288usually contain variable expansions.
1289A common error is trying to use expressions like
1290.Dl ${NUMBERS:M42:?match:no}
1291which actually tests defined(NUMBERS),
1292to determine is any words match "42" you need to use something like:
1293.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1294.It Ar :old_string=new_string
1295This is the
1296.At V
1297style variable substitution.
1298It must be the last modifier specified.
1299If
1300.Ar old_string
1301or
1302.Ar new_string
1303do not contain the pattern matching character
1304.Ar %
1305then it is assumed that they are
1306anchored at the end of each word, so only suffixes or entire
1307words may be replaced.
1308Otherwise
1309.Ar %
1310is the substring of
1311.Ar old_string
1312to be replaced in
1313.Ar new_string .
1314.Pp
1315Variable expansion occurs in the normal fashion inside both
1316.Ar old_string
1317and
1318.Ar new_string
1319with the single exception that a backslash is used to prevent the
1320expansion of a dollar sign
1321.Pq Ql \&$ ,
1322not a preceding dollar sign as is usual.
1323.Sm off
1324.It Cm \&:@ Ar temp Cm @ Ar string Cm @
1325.Sm on
1326This is the loop expansion mechanism from the OSF Development
1327Environment (ODE) make.
1328Unlike
1329.Cm \&.for
1330loops expansion occurs at the time of
1331reference.
1332Assign
1333.Ar temp
1334to each word in the variable and evaluate
1335.Ar string .
1336The ODE convention is that
1337.Ar temp
1338should start and end with a period.
1339For example.
1340.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1341.Pp
1342However a single character variable is often more readable:
1343.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1344.It Cm \&:U Ns Ar newval
1345If the variable is undefined
1346.Ar newval
1347is the value.
1348If the variable is defined, the existing value is returned.
1349This is another ODE make feature.
1350It is handy for setting per-target CFLAGS for instance:
1351.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1352If a value is only required if the variable is undefined, use:
1353.Dl ${VAR:D:Unewval}
1354.It Cm \&:D Ns Ar newval
1355If the variable is defined
1356.Ar newval
1357is the value.
1358.It Cm \&:L
1359The name of the variable is the value.
1360.It Cm \&:P
1361The path of the node which has the same name as the variable
1362is the value.
1363If no such node exists or its path is null, then the
1364name of the variable is used.
1365In order for this modifier to work, the name (node) must at least have
1366appeared on the rhs of a dependency.
1367.Sm off
1368.It Cm \&:\&! Ar cmd Cm \&!
1369.Sm on
1370The output of running
1371.Ar cmd
1372is the value.
1373.It Cm \&:sh
1374If the variable is non-empty it is run as a command and the output
1375becomes the new value.
1376.It Cm \&::= Ns Ar str
1377The variable is assigned the value
1378.Ar str
1379after substitution.
1380This modifier and its variations are useful in
1381obscure situations such as wanting to set a variable when shell commands
1382are being parsed.
1383These assignment modifiers always expand to
1384nothing, so if appearing in a rule line by themselves should be
1385preceded with something to keep
1386.Nm
1387happy.
1388.Pp
1389The
1390.Ql Cm \&::
1391helps avoid false matches with the
1392.At V
1393style
1394.Cm \&:=
1395modifier and since substitution always occurs the
1396.Cm \&::=
1397form is vaguely appropriate.
1398.It Cm \&::?= Ns Ar str
1399As for
1400.Cm \&::=
1401but only if the variable does not already have a value.
1402.It Cm \&::+= Ns Ar str
1403Append
1404.Ar str
1405to the variable.
1406.It Cm \&::!= Ns Ar cmd
1407Assign the output of
1408.Ar cmd
1409to the variable.
1410.It Cm \&:\&[ Ns Ar range Ns Cm \&]
1411Selects one or more words from the value,
1412or performs other operations related to the way in which the
1413value is divided into words.
1414.Pp
1415Ordinarily, a value is treated as a sequence of words
1416delimited by white space.
1417Some modifiers suppress this behaviour,
1418causing a value to be treated as a single word
1419(possibly containing embedded white space).
1420An empty value, or a value that consists entirely of white-space,
1421is treated as a single word.
1422For the purposes of the
1423.Ql Cm \&:[]
1424modifier, the words are indexed both forwards using positive integers
1425(where index 1 represents the first word),
1426and backwards using negative integers
1427(where index \-1 represents the last word).
1428.Pp
1429The
1430.Ar range
1431is subjected to variable expansion, and the expanded result is
1432then interpreted as follows:
1433.Bl -tag -width index
1434.\" :[n]
1435.It Ar index
1436Selects a single word from the value.
1437.\" :[start..end]
1438.It Ar start Ns Cm \&.. Ns Ar end
1439Selects all words from
1440.Ar start
1441to
1442.Ar end ,
1443inclusive.
1444For example,
1445.Ql Cm \&:[2..-1]
1446selects all words from the second word to the last word.
1447If
1448.Ar start
1449is greater than
1450.Ar end ,
1451then the words are output in reverse order.
1452For example,
1453.Ql Cm \&:[-1..1]
1454selects all the words from last to first.
1455.\" :[*]
1456.It Cm \&*
1457Causes subsequent modifiers to treat the value as a single word
1458(possibly containing embedded white space).
1459Analogous to the effect of
1460\&"$*\&"
1461in Bourne shell.
1462.\" :[0]
1463.It 0
1464Means the same as
1465.Ql Cm \&:[*] .
1466.\" :[*]
1467.It Cm \&@
1468Causes subsequent modifiers to treat the value as a sequence of words
1469delimited by white space.
1470Analogous to the effect of
1471\&"$@\&"
1472in Bourne shell.
1473.\" :[#]
1474.It Cm \&#
1475Returns the number of words in the value.
1476.El \" :[range]
1477.El
1478.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1479Makefile inclusion, conditional structures and for loops  reminiscent
1480of the C programming language are provided in
1481.Nm .
1482All such structures are identified by a line beginning with a single
1483dot
1484.Pq Ql \&.
1485character.
1486Files are included with either
1487.Cm \&.include Aq Ar file
1488or
1489.Cm \&.include Pf \*q Ar file Ns \*q .
1490Variables between the angle brackets or double quotes are expanded
1491to form the file name.
1492If angle brackets are used, the included makefile is expected to be in
1493the system makefile directory.
1494If double quotes are used, the including makefile's directory and any
1495directories specified using the
1496.Fl I
1497option are searched before the system
1498makefile directory.
1499For compatibility with other versions of
1500.Nm
1501.Ql include file ...
1502is also accepted.
1503If the include statement is written as
1504.Cm .-include
1505or as
1506.Cm .sinclude
1507then errors locating and/or opening include files are ignored.
1508.Pp
1509Conditional expressions are also preceded by a single dot as the first
1510character of a line.
1511The possible conditionals are as follows:
1512.Bl -tag -width Ds
1513.It Ic .error Ar message
1514The message is printed along with the name of the makefile and line number,
1515then
1516.Nm
1517will exit.
1518.It Ic .export Ar variable ...
1519Export the specified global variable.
1520If no variable list is provided, all globals are exported
1521except for internal variables (those that start with
1522.Ql \&. ) .
1523This is not affected by the
1524.Fl X
1525flag, so should be used with caution.
1526For compatibility with other
1527.Nm
1528programs
1529.Ql export variable=value
1530is also accepted.
1531.Pp
1532Appending a variable name to
1533.Va .MAKE.EXPORTED
1534is equivalent to exporting a variable.
1535.It Ic .export-env Ar variable ...
1536The same as
1537.Ql .export ,
1538except that the variable is not appended to
1539.Va .MAKE.EXPORTED .
1540This allows exporting a value to the environment which is different from that
1541used by
1542.Nm
1543internally.
1544.It Ic .info Ar message
1545The message is printed along with the name of the makefile and line number.
1546.It Ic .undef Ar variable
1547Un-define the specified global variable.
1548Only global variables may be un-defined.
1549.It Ic .unexport Ar variable ...
1550The opposite of
1551.Ql .export .
1552The specified global
1553.Va variable
1554will be removed from
1555.Va .MAKE.EXPORTED .
1556If no variable list is provided, all globals are unexported,
1557and
1558.Va .MAKE.EXPORTED
1559deleted.
1560.It Ic .unexport-env
1561Unexport all globals previously exported and
1562clear the environment inherited from the parent.
1563This operation will cause a memory leak of the original environment,
1564so should be used sparingly.
1565Testing for
1566.Va .MAKE.LEVEL
1567being 0, would make sense.
1568Also note that any variables which originated in the parent environment
1569should be explicitly preserved if desired.
1570For example:
1571.Bd -literal -offset indent
1572.Li .if ${.MAKE.LEVEL} == 0
1573PATH := ${PATH}
1574.Li .unexport-env
1575.Li .export PATH
1576.Li .endif
1577.Pp
1578.Ed
1579Would result in an environment containing only
1580.Ql Ev PATH ,
1581which is the minimal useful environment.
1582Actually
1583.Ql Ev .MAKE.LEVEL
1584will also be pushed into the new environment.
1585.It Ic .warning Ar message
1586The message prefixed by
1587.Ql Pa warning:
1588is printed along with the name of the makefile and line number.
1589.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1590Test the value of an expression.
1591.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1592Test the value of a variable.
1593.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1594Test the value of a variable.
1595.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1596Test the target being built.
1597.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1598Test the target being built.
1599.It Ic .else
1600Reverse the sense of the last conditional.
1601.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1602A combination of
1603.Ql Ic .else
1604followed by
1605.Ql Ic .if .
1606.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1607A combination of
1608.Ql Ic .else
1609followed by
1610.Ql Ic .ifdef .
1611.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1612A combination of
1613.Ql Ic .else
1614followed by
1615.Ql Ic .ifndef .
1616.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1617A combination of
1618.Ql Ic .else
1619followed by
1620.Ql Ic .ifmake .
1621.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1622A combination of
1623.Ql Ic .else
1624followed by
1625.Ql Ic .ifnmake .
1626.It Ic .endif
1627End the body of the conditional.
1628.El
1629.Pp
1630The
1631.Ar operator
1632may be any one of the following:
1633.Bl -tag -width "Cm XX"
1634.It Cm \&|\&|
1635Logical OR.
1636.It Cm \&\*[Am]\*[Am]
1637Logical
1638.Tn AND ;
1639of higher precedence than
1640.Dq \&|\&| .
1641.El
1642.Pp
1643As in C,
1644.Nm
1645will only evaluate a conditional as far as is necessary to determine
1646its value.
1647Parentheses may be used to change the order of evaluation.
1648The boolean operator
1649.Ql Ic \&!
1650may be used to logically negate an entire
1651conditional.
1652It is of higher precedence than
1653.Ql Ic \&\*[Am]\*[Am] .
1654.Pp
1655The value of
1656.Ar expression
1657may be any of the following:
1658.Bl -tag -width defined
1659.It Ic defined
1660Takes a variable name as an argument and evaluates to true if the variable
1661has been defined.
1662.It Ic make
1663Takes a target name as an argument and evaluates to true if the target
1664was specified as part of
1665.Nm Ns 's
1666command line or was declared the default target (either implicitly or
1667explicitly, see
1668.Va .MAIN )
1669before the line containing the conditional.
1670.It Ic empty
1671Takes a variable, with possible modifiers, and evaluates to true if
1672the expansion of the variable would result in an empty string.
1673.It Ic exists
1674Takes a file name as an argument and evaluates to true if the file exists.
1675The file is searched for on the system search path (see
1676.Va .PATH ) .
1677.It Ic target
1678Takes a target name as an argument and evaluates to true if the target
1679has been defined.
1680.It Ic commands
1681Takes a target name as an argument and evaluates to true if the target
1682has been defined and has commands associated with it.
1683.El
1684.Pp
1685.Ar Expression
1686may also be an arithmetic or string comparison.
1687Variable expansion is
1688performed on both sides of the comparison, after which the integral
1689values are compared.
1690A value is interpreted as hexadecimal if it is
1691preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1692The standard C relational operators are all supported.
1693If after
1694variable expansion, either the left or right hand side of a
1695.Ql Ic ==
1696or
1697.Ql Ic "!="
1698operator is not an integral value, then
1699string comparison is performed between the expanded
1700variables.
1701If no relational operator is given, it is assumed that the expanded
1702variable is being compared against 0 or an empty string in the case
1703of a string comparison.
1704.Pp
1705When
1706.Nm
1707is evaluating one of these conditional expressions, and it encounters
1708a (white-space separated) word it doesn't recognize, either the
1709.Dq make
1710or
1711.Dq defined
1712expression is applied to it, depending on the form of the conditional.
1713If the form is
1714.Ql Ic .ifdef ,
1715.Ql Ic .ifndef ,
1716or
1717.Ql Ic .if
1718the
1719.Dq defined
1720expression is applied.
1721Similarly, if the form is
1722.Ql Ic .ifmake
1723or
1724.Ql Ic .ifnmake , the
1725.Dq make
1726expression is applied.
1727.Pp
1728If the conditional evaluates to true the parsing of the makefile continues
1729as before.
1730If it evaluates to false, the following lines are skipped.
1731In both cases this continues until a
1732.Ql Ic .else
1733or
1734.Ql Ic .endif
1735is found.
1736.Pp
1737For loops are typically used to apply a set of rules to a list of files.
1738The syntax of a for loop is:
1739.Pp
1740.Bl -tag -compact -width Ds
1741.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1742.It Aq make-rules
1743.It Ic \&.endfor
1744.El
1745.Pp
1746After the for
1747.Ic expression
1748is evaluated, it is split into words.
1749On each iteration of the loop, one word is taken and assigned to each
1750.Ic variable ,
1751in order, and these
1752.Ic variables
1753are substituted into the
1754.Ic make-rules
1755inside the body of the for loop.
1756The number of words must come out even; that is, if there are three
1757iteration variables, the number of words provided must be a multiple
1758of three.
1759.Sh COMMENTS
1760Comments begin with a hash
1761.Pq Ql \&#
1762character, anywhere but in a shell
1763command line, and continue to the end of an unescaped new line.
1764.Sh SPECIAL SOURCES (ATTRIBUTES)
1765.Bl -tag -width .IGNOREx
1766.It Ic .EXEC
1767Target is never out of date, but always execute commands anyway.
1768.It Ic .IGNORE
1769Ignore any errors from the commands associated with this target, exactly
1770as if they all were preceded by a dash
1771.Pq Ql \- .
1772.\" .It Ic .INVISIBLE
1773.\" XXX
1774.\" .It Ic .JOIN
1775.\" XXX
1776.It Ic .MADE
1777Mark all sources of this target as being up-to-date.
1778.It Ic .MAKE
1779Execute the commands associated with this target even if the
1780.Fl n
1781or
1782.Fl t
1783options were specified.
1784Normally used to mark recursive
1785.Nm Ns s .
1786.It Ic .META
1787Create a meta file for the target, even if it is flagged as
1788.Ic .PHONY ,
1789.Ic .MAKE ,
1790or
1791.Ic .SPECIAL .
1792Usage in conjunction with
1793.Ic .MAKE
1794is the most likely case.
1795In "meta" mode, the target is out-of-date if the meta file is missing.
1796.It Ic .NOMETA
1797Do not create a meta file for the target.
1798Meta files are also not created for
1799.Ic .PHONY ,
1800.Ic .MAKE ,
1801or
1802.Ic .SPECIAL
1803targets.
1804.It Ic .NOMETA_CMP
1805Ignore differences in commands when deciding if target is out of date.
1806This is useful if the command contains a value which always changes.
1807If the number of commands change, though, the target will still be out of date.
1808The same effect applies to any command line that uses the variable
1809.Va .OODATE ,
1810which can be used for that purpose even when not otherwise needed or desired:
1811.Bd -literal -offset indent
1812
1813skip-compare-for-some:
1814	@echo this will be compared
1815	@echo this will not ${.OODATE:M.NOMETA_CMP}
1816	@echo this will also be compared
1817
1818.Ed
1819The
1820.Cm \&:M
1821pattern suppresses any expansion of the unwanted variable.
1822.It Ic .NOPATH
1823Do not search for the target in the directories specified by
1824.Ic .PATH .
1825.It Ic .NOTMAIN
1826Normally
1827.Nm
1828selects the first target it encounters as the default target to be built
1829if no target was specified.
1830This source prevents this target from being selected.
1831.It Ic .OPTIONAL
1832If a target is marked with this attribute and
1833.Nm
1834can't figure out how to create it, it will ignore this fact and assume
1835the file isn't needed or already exists.
1836.It Ic .PHONY
1837The target does not
1838correspond to an actual file; it is always considered to be out of date,
1839and will not be created with the
1840.Fl t
1841option.
1842Suffix-transformation rules are not applied to
1843.Ic .PHONY
1844targets.
1845.It Ic .PRECIOUS
1846When
1847.Nm
1848is interrupted, it normally removes any partially made targets.
1849This source prevents the target from being removed.
1850.It Ic .RECURSIVE
1851Synonym for
1852.Ic .MAKE .
1853.It Ic .SILENT
1854Do not echo any of the commands associated with this target, exactly
1855as if they all were preceded by an at sign
1856.Pq Ql @ .
1857.It Ic .USE
1858Turn the target into
1859.Nm Ns 's
1860version of a macro.
1861When the target is used as a source for another target, the other target
1862acquires the commands, sources, and attributes (except for
1863.Ic .USE )
1864of the
1865source.
1866If the target already has commands, the
1867.Ic .USE
1868target's commands are appended
1869to them.
1870.It Ic .USEBEFORE
1871Exactly like
1872.Ic .USE ,
1873but prepend the
1874.Ic .USEBEFORE
1875target commands to the target.
1876.It Ic .WAIT
1877If
1878.Ic .WAIT
1879appears in a dependency line, the sources that precede it are
1880made before the sources that succeed it in the line.
1881Since the dependents of files are not made until the file itself
1882could be made, this also stops the dependents being built unless they
1883are needed for another branch of the dependency tree.
1884So given:
1885.Bd -literal
1886x: a .WAIT b
1887	echo x
1888a:
1889	echo a
1890b: b1
1891	echo b
1892b1:
1893	echo b1
1894
1895.Ed
1896the output is always
1897.Ql a ,
1898.Ql b1 ,
1899.Ql b ,
1900.Ql x .
1901.br
1902The ordering imposed by
1903.Ic .WAIT
1904is only relevant for parallel makes.
1905.El
1906.Sh SPECIAL TARGETS
1907Special targets may not be included with other targets, i.e. they must be
1908the only target specified.
1909.Bl -tag -width .BEGINx
1910.It Ic .BEGIN
1911Any command lines attached to this target are executed before anything
1912else is done.
1913.It Ic .DEFAULT
1914This is sort of a
1915.Ic .USE
1916rule for any target (that was used only as a
1917source) that
1918.Nm
1919can't figure out any other way to create.
1920Only the shell script is used.
1921The
1922.Ic .IMPSRC
1923variable of a target that inherits
1924.Ic .DEFAULT Ns 's
1925commands is set
1926to the target's own name.
1927.It Ic .END
1928Any command lines attached to this target are executed after everything
1929else is done.
1930.It Ic .ERROR
1931Any command lines attached to this target are executed when another target fails.
1932The
1933.Ic .ERROR_TARGET
1934variable is set to the target that failed.
1935See also
1936.Ic MAKE_PRINT_VAR_ON_ERROR .
1937.It Ic .IGNORE
1938Mark each of the sources with the
1939.Ic .IGNORE
1940attribute.
1941If no sources are specified, this is the equivalent of specifying the
1942.Fl i
1943option.
1944.It Ic .INTERRUPT
1945If
1946.Nm
1947is interrupted, the commands for this target will be executed.
1948.It Ic .MAIN
1949If no target is specified when
1950.Nm
1951is invoked, this target will be built.
1952.It Ic .MAKEFLAGS
1953This target provides a way to specify flags for
1954.Nm
1955when the makefile is used.
1956The flags are as if typed to the shell, though the
1957.Fl f
1958option will have
1959no effect.
1960.\" XXX: NOT YET!!!!
1961.\" .It Ic .NOTPARALLEL
1962.\" The named targets are executed in non parallel mode.
1963.\" If no targets are
1964.\" specified, then all targets are executed in non parallel mode.
1965.It Ic .NOPATH
1966Apply the
1967.Ic .NOPATH
1968attribute to any specified sources.
1969.It Ic .NOTPARALLEL
1970Disable parallel mode.
1971.It Ic .NO_PARALLEL
1972Synonym for
1973.Ic .NOTPARALLEL ,
1974for compatibility with other pmake variants.
1975.It Ic .ORDER
1976The named targets are made in sequence.
1977This ordering does not add targets to the list of targets to be made.
1978Since the dependents of a target do not get built until the target itself
1979could be built, unless
1980.Ql a
1981is built by another part of the dependency graph,
1982the following is a dependency loop:
1983.Bd -literal
1984\&.ORDER: b a
1985b: a
1986.Ed
1987.Pp
1988The ordering imposed by
1989.Ic .ORDER
1990is only relevant for parallel makes.
1991.\" XXX: NOT YET!!!!
1992.\" .It Ic .PARALLEL
1993.\" The named targets are executed in parallel mode.
1994.\" If no targets are
1995.\" specified, then all targets are executed in parallel mode.
1996.It Ic .PATH
1997The sources are directories which are to be searched for files not
1998found in the current directory.
1999If no sources are specified, any previously specified directories are
2000deleted.
2001If the source is the special
2002.Ic .DOTLAST
2003target, then the current working
2004directory is searched last.
2005.It Ic .PATH. Ns Va suffix
2006Like
2007.Ic .PATH
2008but applies only to files with a particular suffix.
2009The suffix must have been previously declared with
2010.Ic .SUFFIXES .
2011.It Ic .PHONY
2012Apply the
2013.Ic .PHONY
2014attribute to any specified sources.
2015.It Ic .PRECIOUS
2016Apply the
2017.Ic .PRECIOUS
2018attribute to any specified sources.
2019If no sources are specified, the
2020.Ic .PRECIOUS
2021attribute is applied to every
2022target in the file.
2023.It Ic .SHELL
2024Sets the shell that
2025.Nm
2026will use to execute commands.
2027The sources are a set of
2028.Ar field=value
2029pairs.
2030.Bl -tag -width hasErrCtls
2031.It Ar name
2032This is the minimal specification, used to select one of the builtin
2033shell specs;
2034.Ar sh ,
2035.Ar ksh ,
2036and
2037.Ar csh .
2038.It Ar path
2039Specifies the path to the shell.
2040.It Ar hasErrCtl
2041Indicates whether the shell supports exit on error.
2042.It Ar check
2043The command to turn on error checking.
2044.It Ar ignore
2045The command to disable error checking.
2046.It Ar echo
2047The command to turn on echoing of commands executed.
2048.It Ar quiet
2049The command to turn off echoing of commands executed.
2050.It Ar filter
2051The output to filter after issuing the
2052.Ar quiet
2053command.
2054It is typically identical to
2055.Ar quiet .
2056.It Ar errFlag
2057The flag to pass the shell to enable error checking.
2058.It Ar echoFlag
2059The flag to pass the shell to enable command echoing.
2060.It Ar newline
2061The string literal to pass the shell that results in a single newline
2062character when used outside of any quoting characters.
2063.El
2064Example:
2065.Bd -literal
2066\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2067	check="set \-e" ignore="set +e" \e
2068	echo="set \-v" quiet="set +v" filter="set +v" \e
2069	echoFlag=v errFlag=e newline="'\en'"
2070.Ed
2071.It Ic .SILENT
2072Apply the
2073.Ic .SILENT
2074attribute to any specified sources.
2075If no sources are specified, the
2076.Ic .SILENT
2077attribute is applied to every
2078command in the file.
2079.It Ic .STALE
2080This target gets run when a dependency file contains stale entries, having
2081.Va .ALLSRC
2082set to the name of that dependency file.
2083.It Ic .SUFFIXES
2084Each source specifies a suffix to
2085.Nm .
2086If no sources are specified, any previously specified suffixes are deleted.
2087It allows the creation of suffix-transformation rules.
2088.Pp
2089Example:
2090.Bd -literal
2091\&.SUFFIXES: .o
2092\&.c.o:
2093	cc \-o ${.TARGET} \-c ${.IMPSRC}
2094.Ed
2095.El
2096.Sh ENVIRONMENT
2097.Nm
2098uses the following environment variables, if they exist:
2099.Ev MACHINE ,
2100.Ev MACHINE_ARCH ,
2101.Ev MAKE ,
2102.Ev MAKEFLAGS ,
2103.Ev MAKEOBJDIR ,
2104.Ev MAKEOBJDIRPREFIX ,
2105.Ev MAKESYSPATH ,
2106.Ev PWD ,
2107and
2108.Ev TMPDIR .
2109.Pp
2110.Ev MAKEOBJDIRPREFIX
2111and
2112.Ev MAKEOBJDIR
2113may only be set in the environment or on the command line to
2114.Nm
2115and not as makefile variables;
2116see the description of
2117.Ql Va .OBJDIR
2118for more details.
2119.Sh FILES
2120.Bl -tag -width /usr/share/mk -compact
2121.It .depend
2122list of dependencies
2123.It Makefile
2124list of dependencies
2125.It makefile
2126list of dependencies
2127.It sys.mk
2128system makefile
2129.It /usr/share/mk
2130system makefile directory
2131.El
2132.Sh COMPATIBILITY
2133The basic make syntax is compatible between different versions of make,
2134however the special variables, variable modifiers and conditionals are not.
2135.Pp
2136The way that parallel makes are scheduled changed in
2137.Nx 4.0
2138so that .ORDER and .WAIT apply recursively to the dependent nodes.
2139The algorithms used may change again in the future.
2140.Pp
2141The way that .for loop variables are substituted changed after
2142.Nx 5.0
2143so that they still appear to be variable expansions.
2144In particular this stops them being treated as syntax, and removes some
2145obscure problems using them in .if statements.
2146.Sh SEE ALSO
2147.Xr mkdep 1
2148.Sh HISTORY
2149A
2150.Nm
2151command appeared in
2152.At v7 .
2153This
2154.Nm
2155implementation is based on Adam De Boor's pmake program which was written
2156for Sprite at Berkeley.
2157It was designed to be a parallel distributed make running jobs on different
2158machines using a daemon called
2159.Dq customs .
2160.Pp
2161Historically the target/dependency
2162.Dq FRC
2163has been used to FoRCe rebuilding (since the target/dependency
2164does not exist... unless someone creates an
2165.Dq FRC
2166file).
2167.Sh BUGS
2168The
2169.Nm
2170syntax is difficult to parse without actually acting of the data.
2171For instance finding the end of a variable use should involve scanning each
2172the modifiers using the correct terminator for each field.
2173In many places
2174.Nm
2175just counts {} and () in order to find the end of a variable expansion.
2176.Pp
2177There is no way of escaping a space character in a filename.
2178