xref: /freebsd/contrib/bmake/make.1 (revision ef0cb5db0af0d5d5b75b74f8e534fe601b7176d7)
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30.\"	from: @(#)make.1	8.4 (Berkeley) 3/19/94
31.\"
32.Dd April 9, 2015
33.Dt MAKE 1
34.Os
35.Sh NAME
36.Nm 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 as a global variable.
1008In all cases,
1009.Nm
1010will
1011.Xr chdir 2
1012to
1013.Ql Va .OBJDIR
1014and set
1015.Ql Ev PWD
1016to that directory before executing any targets.
1017.
1018.It Va .PARSEDIR
1019A path to the directory of the current
1020.Ql Pa Makefile
1021being parsed.
1022.It Va .PARSEFILE
1023The basename of the current
1024.Ql Pa Makefile
1025being parsed.
1026This variable and
1027.Ql Va .PARSEDIR
1028are both set only while the
1029.Ql Pa Makefiles
1030are being parsed.
1031If you want to retain their current values, assign them to a variable
1032using assignment with expansion:
1033.Pq Ql Cm \&:= .
1034.It Va .PATH
1035A variable that represents the list of directories that
1036.Nm
1037will search for files.
1038The search list should be updated using the target
1039.Ql Va .PATH
1040rather than the variable.
1041.It Ev PWD
1042Alternate path to the current directory.
1043.Nm
1044normally sets
1045.Ql Va .CURDIR
1046to the canonical path given by
1047.Xr getcwd 3 .
1048However, if the environment variable
1049.Ql Ev PWD
1050is set and gives a path to the current directory, then
1051.Nm
1052sets
1053.Ql Va .CURDIR
1054to the value of
1055.Ql Ev PWD
1056instead.
1057This behaviour is disabled if
1058.Ql Ev MAKEOBJDIRPREFIX
1059is set or
1060.Ql Ev MAKEOBJDIR
1061contains a variable transform.
1062.Ql Ev PWD
1063is set to the value of
1064.Ql Va .OBJDIR
1065for all programs which
1066.Nm
1067executes.
1068.It Ev .TARGETS
1069The list of targets explicitly specified on the command line, if any.
1070.It Ev VPATH
1071Colon-separated
1072.Pq Dq \&:
1073lists of directories that
1074.Nm
1075will search for files.
1076The variable is supported for compatibility with old make programs only,
1077use
1078.Ql Va .PATH
1079instead.
1080.El
1081.Ss Variable modifiers
1082Variable expansion may be modified to select or modify each word of the
1083variable (where a
1084.Dq word
1085is white-space delimited sequence of characters).
1086The general format of a variable expansion is as follows:
1087.Pp
1088.Dl ${variable[:modifier[:...]]}
1089.Pp
1090Each modifier begins with a colon,
1091which may be escaped with a backslash
1092.Pq Ql \e .
1093.Pp
1094A set of modifiers can be specified via a variable, as follows:
1095.Pp
1096.Dl modifier_variable=modifier[:...]
1097.Dl ${variable:${modifier_variable}[:...]}
1098.Pp
1099In this case the first modifier in the modifier_variable does not
1100start with a colon, since that must appear in the referencing
1101variable.
1102If any of the modifiers in the modifier_variable contain a dollar sign
1103.Pq Ql $ ,
1104these must be doubled to avoid early expansion.
1105.Pp
1106The supported modifiers are:
1107.Bl -tag -width EEE
1108.It Cm \&:E
1109Replaces each word in the variable with its suffix.
1110.It Cm \&:H
1111Replaces each word in the variable with everything but the last component.
1112.It Cm \&:M Ns Ar pattern
1113Select only those words that match
1114.Ar pattern .
1115The standard shell wildcard characters
1116.Pf ( Ql * ,
1117.Ql \&? ,
1118and
1119.Ql Oo Oc )
1120may
1121be used.
1122The wildcard characters may be escaped with a backslash
1123.Pq Ql \e .
1124As a consequence of the way values are split into words, matched,
1125and then joined, a construct like
1126.Dl ${VAR:M*}
1127will normalise the inter-word spacing, removing all leading and
1128trailing space, and converting multiple consecutive spaces
1129to single spaces.
1130.
1131.It Cm \&:N Ns Ar pattern
1132This is identical to
1133.Ql Cm \&:M ,
1134but selects all words which do not match
1135.Ar pattern .
1136.It Cm \&:O
1137Order every word in variable alphabetically.
1138To sort words in
1139reverse order use the
1140.Ql Cm \&:O:[-1..1]
1141combination of modifiers.
1142.It Cm \&:Ox
1143Randomize words in variable.
1144The results will be different each time you are referring to the
1145modified variable; use the assignment with expansion
1146.Pq Ql Cm \&:=
1147to prevent such behaviour.
1148For example,
1149.Bd -literal -offset indent
1150LIST=			uno due tre quattro
1151RANDOM_LIST=		${LIST:Ox}
1152STATIC_RANDOM_LIST:=	${LIST:Ox}
1153
1154all:
1155	@echo "${RANDOM_LIST}"
1156	@echo "${RANDOM_LIST}"
1157	@echo "${STATIC_RANDOM_LIST}"
1158	@echo "${STATIC_RANDOM_LIST}"
1159.Ed
1160may produce output similar to:
1161.Bd -literal -offset indent
1162quattro due tre uno
1163tre due quattro uno
1164due uno quattro tre
1165due uno quattro tre
1166.Ed
1167.It Cm \&:Q
1168Quotes every shell meta-character in the variable, so that it can be passed
1169safely through recursive invocations of
1170.Nm .
1171.It Cm \&:R
1172Replaces each word in the variable with everything but its suffix.
1173.It Cm \&:gmtime
1174The value is a format string for
1175.Xr strftime 3 ,
1176using the current
1177.Xr gmtime 3 .
1178.It Cm \&:hash
1179Compute a 32bit hash of the value and encode it as hex digits.
1180.It Cm \&:localtime
1181The value is a format string for
1182.Xr strftime 3 ,
1183using the current
1184.Xr localtime 3 .
1185.It Cm \&:tA
1186Attempt to convert variable to an absolute path using
1187.Xr realpath 3 ,
1188if that fails, the value is unchanged.
1189.It Cm \&:tl
1190Converts variable to lower-case letters.
1191.It Cm \&:ts Ns Ar c
1192Words in the variable are normally separated by a space on expansion.
1193This modifier sets the separator to the character
1194.Ar c .
1195If
1196.Ar c
1197is omitted, then no separator is used.
1198The common escapes (including octal numeric codes), work as expected.
1199.It Cm \&:tu
1200Converts variable to upper-case letters.
1201.It Cm \&:tW
1202Causes the value to be treated as a single word
1203(possibly containing embedded white space).
1204See also
1205.Ql Cm \&:[*] .
1206.It Cm \&:tw
1207Causes the value to be treated as a sequence of
1208words delimited by white space.
1209See also
1210.Ql Cm \&:[@] .
1211.Sm off
1212.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1213.Sm on
1214Modify the first occurrence of
1215.Ar old_string
1216in the variable's value, replacing it with
1217.Ar new_string .
1218If a
1219.Ql g
1220is appended to the last slash of the pattern, all occurrences
1221in each word are replaced.
1222If a
1223.Ql 1
1224is appended to the last slash of the pattern, only the first word
1225is affected.
1226If a
1227.Ql W
1228is appended to the last slash of the pattern,
1229then the value is treated as a single word
1230(possibly containing embedded white space).
1231If
1232.Ar old_string
1233begins with a caret
1234.Pq Ql ^ ,
1235.Ar old_string
1236is anchored at the beginning of each word.
1237If
1238.Ar old_string
1239ends with a dollar sign
1240.Pq Ql \&$ ,
1241it is anchored at the end of each word.
1242Inside
1243.Ar new_string ,
1244an ampersand
1245.Pq Ql \*[Am]
1246is replaced by
1247.Ar old_string
1248(without any
1249.Ql ^
1250or
1251.Ql \&$ ) .
1252Any character may be used as a delimiter for the parts of the modifier
1253string.
1254The anchoring, ampersand and delimiter characters may be escaped with a
1255backslash
1256.Pq Ql \e .
1257.Pp
1258Variable expansion occurs in the normal fashion inside both
1259.Ar old_string
1260and
1261.Ar new_string
1262with the single exception that a backslash is used to prevent the expansion
1263of a dollar sign
1264.Pq Ql \&$ ,
1265not a preceding dollar sign as is usual.
1266.Sm off
1267.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1268.Sm on
1269The
1270.Cm \&:C
1271modifier is just like the
1272.Cm \&:S
1273modifier except that the old and new strings, instead of being
1274simple strings, are an extended regular expression (see
1275.Xr regex 3 )
1276string
1277.Ar pattern
1278and an
1279.Xr ed 1 Ns \-style
1280string
1281.Ar replacement .
1282Normally, the first occurrence of the pattern
1283.Ar pattern
1284in each word of the value is substituted with
1285.Ar replacement .
1286The
1287.Ql 1
1288modifier causes the substitution to apply to at most one word; the
1289.Ql g
1290modifier causes the substitution to apply to as many instances of the
1291search pattern
1292.Ar pattern
1293as occur in the word or words it is found in; the
1294.Ql W
1295modifier causes the value to be treated as a single word
1296(possibly containing embedded white space).
1297Note that
1298.Ql 1
1299and
1300.Ql g
1301are orthogonal; the former specifies whether multiple words are
1302potentially affected, the latter whether multiple substitutions can
1303potentially occur within each affected word.
1304.Pp
1305As for the
1306.Cm \&:S
1307modifier, the
1308.Ar pattern
1309and
1310.Ar replacement
1311are subjected to variable expansion before being parsed as
1312regular expressions.
1313.It Cm \&:T
1314Replaces each word in the variable with its last component.
1315.It Cm \&:u
1316Remove adjacent duplicate words (like
1317.Xr uniq 1 ) .
1318.Sm off
1319.It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1320.Sm on
1321If the variable name (not its value), when parsed as a .if conditional
1322expression, evaluates to true, return as its value the
1323.Ar true_string ,
1324otherwise return the
1325.Ar false_string .
1326Since the variable name is used as the expression, \&:\&? must be the
1327first modifier after the variable name itself - which will, of course,
1328usually contain variable expansions.
1329A common error is trying to use expressions like
1330.Dl ${NUMBERS:M42:?match:no}
1331which actually tests defined(NUMBERS),
1332to determine is any words match "42" you need to use something like:
1333.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1334.It Ar :old_string=new_string
1335This is the
1336.At V
1337style variable substitution.
1338It must be the last modifier specified.
1339If
1340.Ar old_string
1341or
1342.Ar new_string
1343do not contain the pattern matching character
1344.Ar %
1345then it is assumed that they are
1346anchored at the end of each word, so only suffixes or entire
1347words may be replaced.
1348Otherwise
1349.Ar %
1350is the substring of
1351.Ar old_string
1352to be replaced in
1353.Ar new_string .
1354.Pp
1355Variable expansion occurs in the normal fashion inside both
1356.Ar old_string
1357and
1358.Ar new_string
1359with the single exception that a backslash is used to prevent the
1360expansion of a dollar sign
1361.Pq Ql \&$ ,
1362not a preceding dollar sign as is usual.
1363.Sm off
1364.It Cm \&:@ Ar temp Cm @ Ar string Cm @
1365.Sm on
1366This is the loop expansion mechanism from the OSF Development
1367Environment (ODE) make.
1368Unlike
1369.Cm \&.for
1370loops expansion occurs at the time of
1371reference.
1372Assign
1373.Ar temp
1374to each word in the variable and evaluate
1375.Ar string .
1376The ODE convention is that
1377.Ar temp
1378should start and end with a period.
1379For example.
1380.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1381.Pp
1382However a single character variable is often more readable:
1383.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1384.It Cm \&:U Ns Ar newval
1385If the variable is undefined
1386.Ar newval
1387is the value.
1388If the variable is defined, the existing value is returned.
1389This is another ODE make feature.
1390It is handy for setting per-target CFLAGS for instance:
1391.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1392If a value is only required if the variable is undefined, use:
1393.Dl ${VAR:D:Unewval}
1394.It Cm \&:D Ns Ar newval
1395If the variable is defined
1396.Ar newval
1397is the value.
1398.It Cm \&:L
1399The name of the variable is the value.
1400.It Cm \&:P
1401The path of the node which has the same name as the variable
1402is the value.
1403If no such node exists or its path is null, then the
1404name of the variable is used.
1405In order for this modifier to work, the name (node) must at least have
1406appeared on the rhs of a dependency.
1407.Sm off
1408.It Cm \&:\&! Ar cmd Cm \&!
1409.Sm on
1410The output of running
1411.Ar cmd
1412is the value.
1413.It Cm \&:sh
1414If the variable is non-empty it is run as a command and the output
1415becomes the new value.
1416.It Cm \&::= Ns Ar str
1417The variable is assigned the value
1418.Ar str
1419after substitution.
1420This modifier and its variations are useful in
1421obscure situations such as wanting to set a variable when shell commands
1422are being parsed.
1423These assignment modifiers always expand to
1424nothing, so if appearing in a rule line by themselves should be
1425preceded with something to keep
1426.Nm
1427happy.
1428.Pp
1429The
1430.Ql Cm \&::
1431helps avoid false matches with the
1432.At V
1433style
1434.Cm \&:=
1435modifier and since substitution always occurs the
1436.Cm \&::=
1437form is vaguely appropriate.
1438.It Cm \&::?= Ns Ar str
1439As for
1440.Cm \&::=
1441but only if the variable does not already have a value.
1442.It Cm \&::+= Ns Ar str
1443Append
1444.Ar str
1445to the variable.
1446.It Cm \&::!= Ns Ar cmd
1447Assign the output of
1448.Ar cmd
1449to the variable.
1450.It Cm \&:\&[ Ns Ar range Ns Cm \&]
1451Selects one or more words from the value,
1452or performs other operations related to the way in which the
1453value is divided into words.
1454.Pp
1455Ordinarily, a value is treated as a sequence of words
1456delimited by white space.
1457Some modifiers suppress this behaviour,
1458causing a value to be treated as a single word
1459(possibly containing embedded white space).
1460An empty value, or a value that consists entirely of white-space,
1461is treated as a single word.
1462For the purposes of the
1463.Ql Cm \&:[]
1464modifier, the words are indexed both forwards using positive integers
1465(where index 1 represents the first word),
1466and backwards using negative integers
1467(where index \-1 represents the last word).
1468.Pp
1469The
1470.Ar range
1471is subjected to variable expansion, and the expanded result is
1472then interpreted as follows:
1473.Bl -tag -width index
1474.\" :[n]
1475.It Ar index
1476Selects a single word from the value.
1477.\" :[start..end]
1478.It Ar start Ns Cm \&.. Ns Ar end
1479Selects all words from
1480.Ar start
1481to
1482.Ar end ,
1483inclusive.
1484For example,
1485.Ql Cm \&:[2..-1]
1486selects all words from the second word to the last word.
1487If
1488.Ar start
1489is greater than
1490.Ar end ,
1491then the words are output in reverse order.
1492For example,
1493.Ql Cm \&:[-1..1]
1494selects all the words from last to first.
1495.\" :[*]
1496.It Cm \&*
1497Causes subsequent modifiers to treat the value as a single word
1498(possibly containing embedded white space).
1499Analogous to the effect of
1500\&"$*\&"
1501in Bourne shell.
1502.\" :[0]
1503.It 0
1504Means the same as
1505.Ql Cm \&:[*] .
1506.\" :[*]
1507.It Cm \&@
1508Causes subsequent modifiers to treat the value as a sequence of words
1509delimited by white space.
1510Analogous to the effect of
1511\&"$@\&"
1512in Bourne shell.
1513.\" :[#]
1514.It Cm \&#
1515Returns the number of words in the value.
1516.El \" :[range]
1517.El
1518.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1519Makefile inclusion, conditional structures and for loops  reminiscent
1520of the C programming language are provided in
1521.Nm .
1522All such structures are identified by a line beginning with a single
1523dot
1524.Pq Ql \&.
1525character.
1526Files are included with either
1527.Cm \&.include Aq Ar file
1528or
1529.Cm \&.include Pf \*q Ar file Ns \*q .
1530Variables between the angle brackets or double quotes are expanded
1531to form the file name.
1532If angle brackets are used, the included makefile is expected to be in
1533the system makefile directory.
1534If double quotes are used, the including makefile's directory and any
1535directories specified using the
1536.Fl I
1537option are searched before the system
1538makefile directory.
1539For compatibility with other versions of
1540.Nm
1541.Ql include file ...
1542is also accepted.
1543If the include statement is written as
1544.Cm .-include
1545or as
1546.Cm .sinclude
1547then errors locating and/or opening include files are ignored.
1548.Pp
1549Conditional expressions are also preceded by a single dot as the first
1550character of a line.
1551The possible conditionals are as follows:
1552.Bl -tag -width Ds
1553.It Ic .error Ar message
1554The message is printed along with the name of the makefile and line number,
1555then
1556.Nm
1557will exit.
1558.It Ic .export Ar variable ...
1559Export the specified global variable.
1560If no variable list is provided, all globals are exported
1561except for internal variables (those that start with
1562.Ql \&. ) .
1563This is not affected by the
1564.Fl X
1565flag, so should be used with caution.
1566For compatibility with other
1567.Nm
1568programs
1569.Ql export variable=value
1570is also accepted.
1571.Pp
1572Appending a variable name to
1573.Va .MAKE.EXPORTED
1574is equivalent to exporting a variable.
1575.It Ic .export-env Ar variable ...
1576The same as
1577.Ql .export ,
1578except that the variable is not appended to
1579.Va .MAKE.EXPORTED .
1580This allows exporting a value to the environment which is different from that
1581used by
1582.Nm
1583internally.
1584.It Ic .info Ar message
1585The message is printed along with the name of the makefile and line number.
1586.It Ic .undef Ar variable
1587Un-define the specified global variable.
1588Only global variables may be un-defined.
1589.It Ic .unexport Ar variable ...
1590The opposite of
1591.Ql .export .
1592The specified global
1593.Va variable
1594will be removed from
1595.Va .MAKE.EXPORTED .
1596If no variable list is provided, all globals are unexported,
1597and
1598.Va .MAKE.EXPORTED
1599deleted.
1600.It Ic .unexport-env
1601Unexport all globals previously exported and
1602clear the environment inherited from the parent.
1603This operation will cause a memory leak of the original environment,
1604so should be used sparingly.
1605Testing for
1606.Va .MAKE.LEVEL
1607being 0, would make sense.
1608Also note that any variables which originated in the parent environment
1609should be explicitly preserved if desired.
1610For example:
1611.Bd -literal -offset indent
1612.Li .if ${.MAKE.LEVEL} == 0
1613PATH := ${PATH}
1614.Li .unexport-env
1615.Li .export PATH
1616.Li .endif
1617.Pp
1618.Ed
1619Would result in an environment containing only
1620.Ql Ev PATH ,
1621which is the minimal useful environment.
1622Actually
1623.Ql Ev .MAKE.LEVEL
1624will also be pushed into the new environment.
1625.It Ic .warning Ar message
1626The message prefixed by
1627.Ql Pa warning:
1628is printed along with the name of the makefile and line number.
1629.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1630Test the value of an expression.
1631.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1632Test the value of a variable.
1633.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1634Test the value of a variable.
1635.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1636Test the target being built.
1637.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1638Test the target being built.
1639.It Ic .else
1640Reverse the sense of the last conditional.
1641.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1642A combination of
1643.Ql Ic .else
1644followed by
1645.Ql Ic .if .
1646.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1647A combination of
1648.Ql Ic .else
1649followed by
1650.Ql Ic .ifdef .
1651.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1652A combination of
1653.Ql Ic .else
1654followed by
1655.Ql Ic .ifndef .
1656.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1657A combination of
1658.Ql Ic .else
1659followed by
1660.Ql Ic .ifmake .
1661.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1662A combination of
1663.Ql Ic .else
1664followed by
1665.Ql Ic .ifnmake .
1666.It Ic .endif
1667End the body of the conditional.
1668.El
1669.Pp
1670The
1671.Ar operator
1672may be any one of the following:
1673.Bl -tag -width "Cm XX"
1674.It Cm \&|\&|
1675Logical OR.
1676.It Cm \&\*[Am]\*[Am]
1677Logical
1678.Tn AND ;
1679of higher precedence than
1680.Dq \&|\&| .
1681.El
1682.Pp
1683As in C,
1684.Nm
1685will only evaluate a conditional as far as is necessary to determine
1686its value.
1687Parentheses may be used to change the order of evaluation.
1688The boolean operator
1689.Ql Ic \&!
1690may be used to logically negate an entire
1691conditional.
1692It is of higher precedence than
1693.Ql Ic \&\*[Am]\*[Am] .
1694.Pp
1695The value of
1696.Ar expression
1697may be any of the following:
1698.Bl -tag -width defined
1699.It Ic defined
1700Takes a variable name as an argument and evaluates to true if the variable
1701has been defined.
1702.It Ic make
1703Takes a target name as an argument and evaluates to true if the target
1704was specified as part of
1705.Nm Ns 's
1706command line or was declared the default target (either implicitly or
1707explicitly, see
1708.Va .MAIN )
1709before the line containing the conditional.
1710.It Ic empty
1711Takes a variable, with possible modifiers, and evaluates to true if
1712the expansion of the variable would result in an empty string.
1713.It Ic exists
1714Takes a file name as an argument and evaluates to true if the file exists.
1715The file is searched for on the system search path (see
1716.Va .PATH ) .
1717.It Ic target
1718Takes a target name as an argument and evaluates to true if the target
1719has been defined.
1720.It Ic commands
1721Takes a target name as an argument and evaluates to true if the target
1722has been defined and has commands associated with it.
1723.El
1724.Pp
1725.Ar Expression
1726may also be an arithmetic or string comparison.
1727Variable expansion is
1728performed on both sides of the comparison, after which the integral
1729values are compared.
1730A value is interpreted as hexadecimal if it is
1731preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1732The standard C relational operators are all supported.
1733If after
1734variable expansion, either the left or right hand side of a
1735.Ql Ic ==
1736or
1737.Ql Ic "!="
1738operator is not an integral value, then
1739string comparison is performed between the expanded
1740variables.
1741If no relational operator is given, it is assumed that the expanded
1742variable is being compared against 0 or an empty string in the case
1743of a string comparison.
1744.Pp
1745When
1746.Nm
1747is evaluating one of these conditional expressions, and it encounters
1748a (white-space separated) word it doesn't recognize, either the
1749.Dq make
1750or
1751.Dq defined
1752expression is applied to it, depending on the form of the conditional.
1753If the form is
1754.Ql Ic .ifdef ,
1755.Ql Ic .ifndef ,
1756or
1757.Ql Ic .if
1758the
1759.Dq defined
1760expression is applied.
1761Similarly, if the form is
1762.Ql Ic .ifmake
1763or
1764.Ql Ic .ifnmake , the
1765.Dq make
1766expression is applied.
1767.Pp
1768If the conditional evaluates to true the parsing of the makefile continues
1769as before.
1770If it evaluates to false, the following lines are skipped.
1771In both cases this continues until a
1772.Ql Ic .else
1773or
1774.Ql Ic .endif
1775is found.
1776.Pp
1777For loops are typically used to apply a set of rules to a list of files.
1778The syntax of a for loop is:
1779.Pp
1780.Bl -tag -compact -width Ds
1781.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1782.It Aq make-rules
1783.It Ic \&.endfor
1784.El
1785.Pp
1786After the for
1787.Ic expression
1788is evaluated, it is split into words.
1789On each iteration of the loop, one word is taken and assigned to each
1790.Ic variable ,
1791in order, and these
1792.Ic variables
1793are substituted into the
1794.Ic make-rules
1795inside the body of the for loop.
1796The number of words must come out even; that is, if there are three
1797iteration variables, the number of words provided must be a multiple
1798of three.
1799.Sh COMMENTS
1800Comments begin with a hash
1801.Pq Ql \&#
1802character, anywhere but in a shell
1803command line, and continue to the end of an unescaped new line.
1804.Sh SPECIAL SOURCES (ATTRIBUTES)
1805.Bl -tag -width .IGNOREx
1806.It Ic .EXEC
1807Target is never out of date, but always execute commands anyway.
1808.It Ic .IGNORE
1809Ignore any errors from the commands associated with this target, exactly
1810as if they all were preceded by a dash
1811.Pq Ql \- .
1812.\" .It Ic .INVISIBLE
1813.\" XXX
1814.\" .It Ic .JOIN
1815.\" XXX
1816.It Ic .MADE
1817Mark all sources of this target as being up-to-date.
1818.It Ic .MAKE
1819Execute the commands associated with this target even if the
1820.Fl n
1821or
1822.Fl t
1823options were specified.
1824Normally used to mark recursive
1825.Nm Ns s .
1826.It Ic .META
1827Create a meta file for the target, even if it is flagged as
1828.Ic .PHONY ,
1829.Ic .MAKE ,
1830or
1831.Ic .SPECIAL .
1832Usage in conjunction with
1833.Ic .MAKE
1834is the most likely case.
1835In "meta" mode, the target is out-of-date if the meta file is missing.
1836.It Ic .NOMETA
1837Do not create a meta file for the target.
1838Meta files are also not created for
1839.Ic .PHONY ,
1840.Ic .MAKE ,
1841or
1842.Ic .SPECIAL
1843targets.
1844.It Ic .NOMETA_CMP
1845Ignore differences in commands when deciding if target is out of date.
1846This is useful if the command contains a value which always changes.
1847If the number of commands change, though, the target will still be out of date.
1848The same effect applies to any command line that uses the variable
1849.Va .OODATE ,
1850which can be used for that purpose even when not otherwise needed or desired:
1851.Bd -literal -offset indent
1852
1853skip-compare-for-some:
1854	@echo this will be compared
1855	@echo this will not ${.OODATE:M.NOMETA_CMP}
1856	@echo this will also be compared
1857
1858.Ed
1859The
1860.Cm \&:M
1861pattern suppresses any expansion of the unwanted variable.
1862.It Ic .NOPATH
1863Do not search for the target in the directories specified by
1864.Ic .PATH .
1865.It Ic .NOTMAIN
1866Normally
1867.Nm
1868selects the first target it encounters as the default target to be built
1869if no target was specified.
1870This source prevents this target from being selected.
1871.It Ic .OPTIONAL
1872If a target is marked with this attribute and
1873.Nm
1874can't figure out how to create it, it will ignore this fact and assume
1875the file isn't needed or already exists.
1876.It Ic .PHONY
1877The target does not
1878correspond to an actual file; it is always considered to be out of date,
1879and will not be created with the
1880.Fl t
1881option.
1882Suffix-transformation rules are not applied to
1883.Ic .PHONY
1884targets.
1885.It Ic .PRECIOUS
1886When
1887.Nm
1888is interrupted, it normally removes any partially made targets.
1889This source prevents the target from being removed.
1890.It Ic .RECURSIVE
1891Synonym for
1892.Ic .MAKE .
1893.It Ic .SILENT
1894Do not echo any of the commands associated with this target, exactly
1895as if they all were preceded by an at sign
1896.Pq Ql @ .
1897.It Ic .USE
1898Turn the target into
1899.Nm Ns 's
1900version of a macro.
1901When the target is used as a source for another target, the other target
1902acquires the commands, sources, and attributes (except for
1903.Ic .USE )
1904of the
1905source.
1906If the target already has commands, the
1907.Ic .USE
1908target's commands are appended
1909to them.
1910.It Ic .USEBEFORE
1911Exactly like
1912.Ic .USE ,
1913but prepend the
1914.Ic .USEBEFORE
1915target commands to the target.
1916.It Ic .WAIT
1917If
1918.Ic .WAIT
1919appears in a dependency line, the sources that precede it are
1920made before the sources that succeed it in the line.
1921Since the dependents of files are not made until the file itself
1922could be made, this also stops the dependents being built unless they
1923are needed for another branch of the dependency tree.
1924So given:
1925.Bd -literal
1926x: a .WAIT b
1927	echo x
1928a:
1929	echo a
1930b: b1
1931	echo b
1932b1:
1933	echo b1
1934
1935.Ed
1936the output is always
1937.Ql a ,
1938.Ql b1 ,
1939.Ql b ,
1940.Ql x .
1941.br
1942The ordering imposed by
1943.Ic .WAIT
1944is only relevant for parallel makes.
1945.El
1946.Sh SPECIAL TARGETS
1947Special targets may not be included with other targets, i.e. they must be
1948the only target specified.
1949.Bl -tag -width .BEGINx
1950.It Ic .BEGIN
1951Any command lines attached to this target are executed before anything
1952else is done.
1953.It Ic .DEFAULT
1954This is sort of a
1955.Ic .USE
1956rule for any target (that was used only as a
1957source) that
1958.Nm
1959can't figure out any other way to create.
1960Only the shell script is used.
1961The
1962.Ic .IMPSRC
1963variable of a target that inherits
1964.Ic .DEFAULT Ns 's
1965commands is set
1966to the target's own name.
1967.It Ic .END
1968Any command lines attached to this target are executed after everything
1969else is done.
1970.It Ic .ERROR
1971Any command lines attached to this target are executed when another target fails.
1972The
1973.Ic .ERROR_TARGET
1974variable is set to the target that failed.
1975See also
1976.Ic MAKE_PRINT_VAR_ON_ERROR .
1977.It Ic .IGNORE
1978Mark each of the sources with the
1979.Ic .IGNORE
1980attribute.
1981If no sources are specified, this is the equivalent of specifying the
1982.Fl i
1983option.
1984.It Ic .INTERRUPT
1985If
1986.Nm
1987is interrupted, the commands for this target will be executed.
1988.It Ic .MAIN
1989If no target is specified when
1990.Nm
1991is invoked, this target will be built.
1992.It Ic .MAKEFLAGS
1993This target provides a way to specify flags for
1994.Nm
1995when the makefile is used.
1996The flags are as if typed to the shell, though the
1997.Fl f
1998option will have
1999no effect.
2000.\" XXX: NOT YET!!!!
2001.\" .It Ic .NOTPARALLEL
2002.\" The named targets are executed in non parallel mode.
2003.\" If no targets are
2004.\" specified, then all targets are executed in non parallel mode.
2005.It Ic .NOPATH
2006Apply the
2007.Ic .NOPATH
2008attribute to any specified sources.
2009.It Ic .NOTPARALLEL
2010Disable parallel mode.
2011.It Ic .NO_PARALLEL
2012Synonym for
2013.Ic .NOTPARALLEL ,
2014for compatibility with other pmake variants.
2015.It Ic .ORDER
2016The named targets are made in sequence.
2017This ordering does not add targets to the list of targets to be made.
2018Since the dependents of a target do not get built until the target itself
2019could be built, unless
2020.Ql a
2021is built by another part of the dependency graph,
2022the following is a dependency loop:
2023.Bd -literal
2024\&.ORDER: b a
2025b: a
2026.Ed
2027.Pp
2028The ordering imposed by
2029.Ic .ORDER
2030is only relevant for parallel makes.
2031.\" XXX: NOT YET!!!!
2032.\" .It Ic .PARALLEL
2033.\" The named targets are executed in parallel mode.
2034.\" If no targets are
2035.\" specified, then all targets are executed in parallel mode.
2036.It Ic .PATH
2037The sources are directories which are to be searched for files not
2038found in the current directory.
2039If no sources are specified, any previously specified directories are
2040deleted.
2041If the source is the special
2042.Ic .DOTLAST
2043target, then the current working
2044directory is searched last.
2045.It Ic .PATH. Ns Va suffix
2046Like
2047.Ic .PATH
2048but applies only to files with a particular suffix.
2049The suffix must have been previously declared with
2050.Ic .SUFFIXES .
2051.It Ic .PHONY
2052Apply the
2053.Ic .PHONY
2054attribute to any specified sources.
2055.It Ic .PRECIOUS
2056Apply the
2057.Ic .PRECIOUS
2058attribute to any specified sources.
2059If no sources are specified, the
2060.Ic .PRECIOUS
2061attribute is applied to every
2062target in the file.
2063.It Ic .SHELL
2064Sets the shell that
2065.Nm
2066will use to execute commands.
2067The sources are a set of
2068.Ar field=value
2069pairs.
2070.Bl -tag -width hasErrCtls
2071.It Ar name
2072This is the minimal specification, used to select one of the builtin
2073shell specs;
2074.Ar sh ,
2075.Ar ksh ,
2076and
2077.Ar csh .
2078.It Ar path
2079Specifies the path to the shell.
2080.It Ar hasErrCtl
2081Indicates whether the shell supports exit on error.
2082.It Ar check
2083The command to turn on error checking.
2084.It Ar ignore
2085The command to disable error checking.
2086.It Ar echo
2087The command to turn on echoing of commands executed.
2088.It Ar quiet
2089The command to turn off echoing of commands executed.
2090.It Ar filter
2091The output to filter after issuing the
2092.Ar quiet
2093command.
2094It is typically identical to
2095.Ar quiet .
2096.It Ar errFlag
2097The flag to pass the shell to enable error checking.
2098.It Ar echoFlag
2099The flag to pass the shell to enable command echoing.
2100.It Ar newline
2101The string literal to pass the shell that results in a single newline
2102character when used outside of any quoting characters.
2103.El
2104Example:
2105.Bd -literal
2106\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2107	check="set \-e" ignore="set +e" \e
2108	echo="set \-v" quiet="set +v" filter="set +v" \e
2109	echoFlag=v errFlag=e newline="'\en'"
2110.Ed
2111.It Ic .SILENT
2112Apply the
2113.Ic .SILENT
2114attribute to any specified sources.
2115If no sources are specified, the
2116.Ic .SILENT
2117attribute is applied to every
2118command in the file.
2119.It Ic .STALE
2120This target gets run when a dependency file contains stale entries, having
2121.Va .ALLSRC
2122set to the name of that dependency file.
2123.It Ic .SUFFIXES
2124Each source specifies a suffix to
2125.Nm .
2126If no sources are specified, any previously specified suffixes are deleted.
2127It allows the creation of suffix-transformation rules.
2128.Pp
2129Example:
2130.Bd -literal
2131\&.SUFFIXES: .o
2132\&.c.o:
2133	cc \-o ${.TARGET} \-c ${.IMPSRC}
2134.Ed
2135.El
2136.Sh ENVIRONMENT
2137.Nm
2138uses the following environment variables, if they exist:
2139.Ev MACHINE ,
2140.Ev MACHINE_ARCH ,
2141.Ev MAKE ,
2142.Ev MAKEFLAGS ,
2143.Ev MAKEOBJDIR ,
2144.Ev MAKEOBJDIRPREFIX ,
2145.Ev MAKESYSPATH ,
2146.Ev PWD ,
2147and
2148.Ev TMPDIR .
2149.Pp
2150.Ev MAKEOBJDIRPREFIX
2151and
2152.Ev MAKEOBJDIR
2153may only be set in the environment or on the command line to
2154.Nm
2155and not as makefile variables;
2156see the description of
2157.Ql Va .OBJDIR
2158for more details.
2159.Sh FILES
2160.Bl -tag -width /usr/share/mk -compact
2161.It .depend
2162list of dependencies
2163.It Makefile
2164list of dependencies
2165.It makefile
2166list of dependencies
2167.It sys.mk
2168system makefile
2169.It /usr/share/mk
2170system makefile directory
2171.El
2172.Sh COMPATIBILITY
2173The basic make syntax is compatible between different versions of make;
2174however the special variables, variable modifiers and conditionals are not.
2175.Ss Older versions
2176An incomplete list of changes in older versions of
2177.Nm :
2178.Pp
2179The way that .for loop variables are substituted changed after
2180.Nx 5.0
2181so that they still appear to be variable expansions.
2182In particular this stops them being treated as syntax, and removes some
2183obscure problems using them in .if statements.
2184.Pp
2185The way that parallel makes are scheduled changed in
2186.Nx 4.0
2187so that .ORDER and .WAIT apply recursively to the dependent nodes.
2188The algorithms used may change again in the future.
2189.Ss Other make dialects
2190Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
2191support most of the features of
2192.Nm
2193as described in this manual.
2194Most notably:
2195.Bl -bullet -offset indent
2196.It
2197The
2198.Ic .WAIT
2199and
2200.Ic .ORDER
2201declarations and most functionality pertaining to parallelization.
2202(GNU make supports parallelization but lacks these features needed to
2203control it effectively.)
2204.It
2205Directives, including for loops and conditionals and most of the
2206forms of include files.
2207(GNU make has its own incompatible and less powerful syntax for
2208conditionals.)
2209.It
2210All built-in variables that begin with a dot.
2211.It
2212Most of the special sources and targets that begin with a dot,
2213with the notable exception of
2214.Ic .PHONY ,
2215.Ic .PRECIOUS ,
2216and
2217.Ic .SUFFIXES .
2218.It
2219Variable modifiers, except for the
2220.Dl :old=new
2221string substitution, which does not portably support globbing with
2222.Ql %
2223and historically only works on declared suffixes.
2224.It
2225The
2226.Ic $>
2227variable even in its short form; most makes support this functionality
2228but its name varies.
2229.El
2230.Pp
2231Some features are somewhat more portable, such as assignment with
2232.Ic += ,
2233.Ic ?= ,
2234and
2235.Ic != .
2236The
2237.Ic .PATH
2238functionality is based on an older feature
2239.Ic VPATH
2240found in GNU make and many versions of SVR4 make; however,
2241historically its behavior is too ill-defined (and too buggy) to rely
2242upon.
2243.Pp
2244The
2245.Ic $@
2246and
2247.Ic $<
2248variables are more or less universally portable, as is the
2249.Ic $(MAKE)
2250variable.
2251Basic use of suffix rules (for files only in the current directory,
2252not trying to chain transformations together, etc.) is also reasonably
2253portable.
2254.Sh SEE ALSO
2255.Xr mkdep 1
2256.Sh HISTORY
2257A
2258.Nm
2259command appeared in
2260.At v7 .
2261This
2262.Nm
2263implementation is based on Adam De Boor's pmake program which was written
2264for Sprite at Berkeley.
2265It was designed to be a parallel distributed make running jobs on different
2266machines using a daemon called
2267.Dq customs .
2268.Pp
2269Historically the target/dependency
2270.Dq FRC
2271has been used to FoRCe rebuilding (since the target/dependency
2272does not exist... unless someone creates an
2273.Dq FRC
2274file).
2275.Sh BUGS
2276The
2277.Nm
2278syntax is difficult to parse without actually acting of the data.
2279For instance finding the end of a variable use should involve scanning each
2280the modifiers using the correct terminator for each field.
2281In many places
2282.Nm
2283just counts {} and () in order to find the end of a variable expansion.
2284.Pp
2285There is no way of escaping a space character in a filename.
2286