xref: /freebsd/contrib/bmake/bmake.1 (revision 8c784bb8cf36911b828652f0bf7e88f443abec50)
1.\"	$NetBSD: make.1,v 1.360 2023/01/26 20:48:17 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 January 26, 2023
33.Dt BMAKE 1
34.Os
35.Sh NAME
36.Nm bmake
37.Nd maintain program dependencies
38.Sh SYNOPSIS
39.Nm
40.Op Fl BeikNnqrSstWwX
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 Fl v Ar variable
52.Op Ar variable\| Ns Cm \&= Ns Ar value
53.Op Ar target No ...
54.Sh DESCRIPTION
55.Nm
56is a program designed to simplify the maintenance of other programs.
57Its input is a list of specifications as to the files upon which programs
58and other files depend.
59If no
60.Fl f Ar makefile
61option is given,
62.Nm
63tries to open
64.Sq Pa makefile
65then
66.Sq Pa Makefile
67in order to find the specifications.
68If the file
69.Sq Pa .depend
70exists, it is read, see
71.Xr mkdep 1 .
72.Pp
73This manual page is intended as a reference document only.
74For a more thorough description of
75.Nm
76and makefiles, please refer to
77.%T "PMake \- A Tutorial"
78(from 1993).
79.Pp
80.Nm
81prepends the contents of the
82.Ev MAKEFLAGS
83environment variable to the command line arguments before parsing them.
84.Pp
85The options are as follows:
86.Bl -tag -width Ds
87.It Fl B
88Try to be backwards compatible by executing a single shell per command and
89by making the sources of a dependency line in sequence.
90.It Fl C Ar directory
91Change to
92.Ar directory
93before reading the makefiles or doing anything else.
94If multiple
95.Fl C
96options are specified, each is interpreted relative to the previous one:
97.Fl C Pa / Fl C Pa etc
98is equivalent to
99.Fl C Pa /etc .
100.It Fl D Ar variable
101Define
102.Ar variable
103to be 1, in the global scope.
104.It Fl d Oo Cm \- Oc Ns Ar flags
105Turn on debugging, and specify which portions of
106.Nm
107are to print debugging information.
108Unless the flags are preceded by
109.Ql \- ,
110they are added to the
111.Ev MAKEFLAGS
112environment variable and are passed on to any child make processes.
113By default, debugging information is printed to standard error,
114but this can be changed using the
115.Cm F
116debugging flag.
117The debugging output is always unbuffered; in addition, if debugging
118is enabled but debugging output is not directed to standard output,
119the standard output is line buffered.
120The available
121.Ar flags
122are:
123.Bl -tag -width Ds
124.It Cm A
125Print all possible debugging information;
126equivalent to specifying all of the debugging flags.
127.It Cm a
128Print debugging information about archive searching and caching.
129.It Cm C
130Print debugging information about the current working directory.
131.It Cm c
132Print debugging information about conditional evaluation.
133.It Cm d
134Print debugging information about directory searching and caching.
135.It Cm e
136Print debugging information about failed commands and targets.
137.It Cm F Ns Oo Cm \&+ Oc Ns Ar filename
138Specify where debugging output is written.
139This must be the last flag, because it consumes the remainder of
140the argument.
141If the character immediately after the
142.Cm F
143flag is
144.Ql \&+ ,
145the file is opened in append mode;
146otherwise the file is overwritten.
147If the file name is
148.Ql stdout
149or
150.Ql stderr ,
151debugging output is written to the standard output or standard error output
152respectively (and the
153.Ql \&+
154option has no effect).
155Otherwise, the output is written to the named file.
156If the file name ends with
157.Ql .%d ,
158the
159.Ql %d
160is replaced by the pid.
161.It Cm f
162Print debugging information about loop evaluation.
163.It Cm g1
164Print the input graph before making anything.
165.It Cm g2
166Print the input graph after making everything, or before exiting
167on error.
168.It Cm g3
169Print the input graph before exiting on error.
170.It Cm h
171Print debugging information about hash table operations.
172.It Cm j
173Print debugging information about running multiple shells.
174.It Cm L
175Turn on lint checks.
176This throws errors for variable assignments that do not parse correctly,
177at the time of assignment, so the file and line number are available.
178.It Cm l
179Print commands in Makefiles regardless of whether or not they are prefixed by
180.Ql @
181or other
182.Dq quiet
183flags.
184Also known as
185.Dq loud
186behavior.
187.It Cm M
188Print debugging information about
189.Dq meta
190mode decisions about targets.
191.It Cm m
192Print debugging information about making targets, including modification
193dates.
194.It Cm n
195Don't delete the temporary command scripts created when running commands.
196These temporary scripts are created in the directory
197referred to by the
198.Ev TMPDIR
199environment variable, or in
200.Pa /tmp
201if
202.Ev TMPDIR
203is unset or set to the empty string.
204The temporary scripts are created by
205.Xr mkstemp 3 ,
206and have names of the form
207.Pa makeXXXXXX .
208.Em NOTE :
209This can create many files in
210.Ev TMPDIR
211or
212.Pa /tmp ,
213so use with care.
214.It Cm p
215Print debugging information about makefile parsing.
216.It Cm s
217Print debugging information about suffix-transformation rules.
218.It Cm t
219Print debugging information about target list maintenance.
220.It Cm V
221Force the
222.Fl V
223option to print raw values of variables,
224overriding the default behavior set via
225.Va .MAKE.EXPAND_VARIABLES .
226.It Cm v
227Print debugging information about variable assignment and expansion.
228.It Cm x
229Run shell commands with
230.Fl x
231so the actual commands are printed as they are executed.
232.El
233.It Fl e
234Let environment variables override global variables within makefiles.
235.It Fl f Ar makefile
236Specify a makefile to read instead of the default
237.Pa makefile
238or
239.Pa Makefile .
240If
241.Ar makefile
242is
243.Ql \&- ,
244standard input is read.
245Multiple makefiles may be specified, and are read in the order specified.
246.It Fl I Ar directory
247Specify a directory in which to search for makefiles and included makefiles.
248The system makefile directory (or directories, see the
249.Fl m
250option) is automatically included as part of this list.
251.It Fl i
252Ignore non-zero exit of shell commands in the makefile.
253Equivalent to specifying
254.Ql \&-
255before each command line in the makefile.
256.It Fl J Ar private
257This option should
258.Em not
259be specified by the user.
260.Pp
261When the
262.Fl j
263option is in use in a recursive build, this option is passed by a make
264to child makes to allow all the make processes in the build to
265cooperate to avoid overloading the system.
266.It Fl j Ar max_jobs
267Specify the maximum number of jobs that
268.Nm
269may have running at any one time.
270The value is saved in
271.Va .MAKE.JOBS .
272Turns compatibility mode off, unless the
273.Fl B
274option is also specified.
275When compatibility mode is off, all commands associated with a
276target are executed in a single shell invocation as opposed to the
277traditional one shell invocation per line.
278This can break traditional scripts which change directories on each
279command invocation and then expect to start with a fresh environment
280on the next line.
281It is more efficient to correct the scripts rather than turn backwards
282compatibility on.
283.It Fl k
284Continue processing after errors are encountered, but only on those targets
285that do not depend on the target whose creation caused the error.
286.It Fl m Ar directory
287Specify a directory in which to search for
288.Pa sys.mk
289and makefiles included via the
290.Li \&< Ns Ar file Ns Li \&> Ns -style
291include statement.
292The
293.Fl m
294option can be used multiple times to form a search path.
295This path overrides the default system include path
296.Pa /usr/share/mk .
297Furthermore, the system include path is appended to the search path used for
298.Li \*q Ns Ar file Ns Li \*q Ns -style
299include statements (see the
300.Fl I
301option).
302The system include path can be referenced via the read-only variable
303.Va .SYSPATH .
304.Pp
305If a directory name in the
306.Fl m
307argument (or the
308.Ev MAKESYSPATH
309environment variable) starts with the string
310.Ql \&.../ ,
311.Nm
312searches for the specified file or directory named in the remaining part
313of the argument string.
314The search starts with the current directory
315and then works upward towards the root of the file system.
316If the search is successful, the resulting directory replaces the
317.Ql \&.../
318specification in the
319.Fl m
320argument.
321This feature allows
322.Nm
323to easily search in the current source tree for customized
324.Pa sys.mk
325files (e.g., by using
326.Ql \&.../mk/sys.mk
327as an argument).
328.It Fl n
329Display the commands that would have been executed, but do not
330actually execute them unless the target depends on the
331.Va .MAKE
332special source (see below) or the command is prefixed with
333.Sq Cm + .
334.It Fl N
335Display the commands that would have been executed,
336but do not actually execute any of them;
337useful for debugging top-level makefiles
338without descending into subdirectories.
339.It Fl q
340Do not execute any commands,
341instead exit 0 if the specified targets are up to date, and 1 otherwise.
342.It Fl r
343Do not use the built-in rules specified in the system makefile.
344.It Fl S
345Stop processing if an error is encountered.
346This is the default behavior and the opposite of
347.Fl k .
348.It Fl s
349Do not echo any commands as they are executed.
350Equivalent to specifying
351.Sq Ic @
352before each command line in the makefile.
353.It Fl T Ar tracefile
354When used with the
355.Fl j
356flag,
357append a trace record to
358.Ar tracefile
359for each job started and completed.
360.It Fl t
361Rather than re-building a target as specified in the makefile, create it
362or update its modification time to make it appear up-to-date.
363.It Fl V Ar variable
364Print the value of
365.Ar variable .
366Do not build any targets.
367Multiple instances of this option may be specified;
368the variables are printed one per line,
369with a blank line for each null or undefined variable.
370The value printed is extracted from the global scope after all
371makefiles have been read.
372.Pp
373By default, the raw variable contents (which may
374include additional unexpanded variable references) are shown.
375If
376.Ar variable
377contains a
378.Ql \&$ ,
379it is not interpreted as a variable name but rather as an expression.
380Its value is expanded before printing.
381The value is also expanded before printing if
382.Va .MAKE.EXPAND_VARIABLES
383is set to true and the
384.Fl dV
385option has not been used to override it.
386.Pp
387Note that loop-local and target-local variables, as well as values
388taken temporarily by global variables during makefile processing, are
389not accessible via this option.
390The
391.Fl dv
392debug mode can be used to see these at the cost of generating
393substantial extraneous output.
394.It Fl v Ar variable
395Like
396.Fl V ,
397but all printed variables are always expanded to their complete value.
398The last occurrence of
399.Fl V
400or
401.Fl v
402decides whether all variables are expanded or not.
403.It Fl W
404Treat any warnings during makefile parsing as errors.
405.It Fl w
406Print entering and leaving directory messages, pre and post processing.
407.It Fl X
408Don't export variables passed on the command line to the environment
409individually.
410Variables passed on the command line are still exported via the
411.Ev MAKEFLAGS
412environment variable.
413This option may be useful on systems which have a small limit on the
414size of command arguments.
415.It Ar variable\| Ns Cm \&= Ns Ar value
416Set the value of the variable
417.Ar variable
418to
419.Ar value .
420Normally, all values passed on the command line are also exported to
421sub-makes in the environment.
422The
423.Fl X
424flag disables this behavior.
425Variable assignments should follow options for POSIX compatibility
426but no ordering is enforced.
427.El
428.Pp
429There are several different types of lines in a makefile: dependency
430specifications, shell commands, variable assignments, include statements,
431conditional directives, for loops, other directives, and comments.
432.Pp
433Lines may be continued from one line to the next
434by ending them with a backslash
435.Pq Ql \e .
436The trailing newline character and initial whitespace on the following
437line are compressed into a single space.
438.Sh FILE DEPENDENCY SPECIFICATIONS
439Dependency lines consist of one or more targets, an operator, and zero
440or more sources.
441This creates a relationship where the targets
442.Dq depend
443on the sources and are customarily created from them.
444A target is considered out of date if it does not exist,
445or if its modification time is less than that of any of its sources.
446An out-of-date target is re-created, but not until all sources
447have been examined and themselves re-created as needed.
448Three operators may be used:
449.Bl -tag -width flag
450.It Ic \&:
451Many dependency lines may name this target but only one may have
452attached shell commands.
453All sources named in all dependency lines are considered together,
454and if needed the attached shell commands are run to create or
455re-create the target.
456If
457.Nm
458is interrupted, the target is removed.
459.It Ic \&!
460The same, but the target is always re-created whether or not it is out
461of date.
462.It Ic \&::
463Any dependency line may have attached shell commands, but each one
464is handled independently: its sources are considered and the attached
465shell commands are run if the target is out of date with respect to
466(only) those sources.
467Thus, different groups of the attached shell commands may be run
468depending on the circumstances.
469Furthermore, unlike
470.Ic \&: ,
471for dependency lines with no sources, the attached shell
472commands are always run.
473Also unlike
474.Ic \&: ,
475the target is not removed if
476.Nm
477is interrupted.
478.El
479.Pp
480All dependency lines mentioning a particular target must use the same
481operator.
482.Pp
483Targets and sources may contain the shell wildcard values
484.Ql \&? ,
485.Ql * ,
486.Ql [] ,
487and
488.Ql {} .
489The values
490.Ql \&? ,
491.Ql * ,
492and
493.Ql []
494may only be used as part of the final component of the target or source,
495and only match existing files.
496The value
497.Ql {}
498need not necessarily be used to describe existing files.
499Expansion is in directory order, not alphabetically as done in the shell.
500.Sh SHELL COMMANDS
501Each target may have associated with it one or more lines of shell commands,
502normally used to create the target.
503Each of the lines in this script
504.Em must
505be preceded by a tab.
506(For historical reasons, spaces are not accepted.)
507While targets can occur in many dependency lines if desired,
508by default only one of these rules may be followed by a creation script.
509If the
510.Sq Ic \&::
511operator is used, however, all rules may include scripts,
512and the respective scripts are executed in the order found.
513.Pp
514Each line is treated as a separate shell command,
515unless the end of line is escaped with a backslash
516.Ql \e ,
517in which case that line and the next are combined.
518If the first characters of the command are any combination of
519.Sq Ic @ ,
520.Sq Ic + ,
521or
522.Sq Ic \- ,
523the command is treated specially.
524.Bl -tag -offset indent -width indent
525.It Ic @
526causes the command not to be echoed before it is executed.
527.It Ic +
528causes the command to be executed even when
529.Fl n
530is given.
531This is similar to the effect of the
532.Va .MAKE
533special source,
534except that the effect can be limited to a single line of a script.
535.It Ic \-
536in compatibility mode
537causes any non-zero exit status of the command line to be ignored.
538.El
539.Pp
540When
541.Nm
542is run in jobs mode with
543.Fl j Ar max_jobs ,
544the entire script for the target is fed to a single instance of the shell.
545In compatibility (non-jobs) mode, each command is run in a separate process.
546If the command contains any shell meta characters
547.Pq Ql #=|^(){};&<>*?[]:$`\e\en ,
548it is passed to the shell; otherwise
549.Nm
550attempts direct execution.
551If a line starts with
552.Sq Ic \-
553and the shell has ErrCtl enabled,
554failure of the command line is ignored as in compatibility mode.
555Otherwise
556.Sq Ic \-
557affects the entire job;
558the script stops at the first command line that fails,
559but the target is not deemed to have failed.
560.Pp
561Makefiles should be written so that the mode of
562.Nm
563operation does not change their behavior.
564For example, any command which uses
565.Dq cd
566or
567.Dq chdir
568without the intention of changing the directory for subsequent commands
569should be put in parentheses so it executes in a subshell.
570To force the use of a single shell, escape the line breaks so as to make
571the whole script one command.
572For example:
573.Bd -literal -offset indent
574avoid-chdir-side-effects:
575	@echo "Building $@ in $$(pwd)"
576	@(cd ${.CURDIR} && ${MAKE} $@)
577	@echo "Back in $$(pwd)"
578
579ensure-one-shell-regardless-of-mode:
580	@echo "Building $@ in $$(pwd)"; \e
581	(cd ${.CURDIR} && ${MAKE} $@); \e
582	echo "Back in $$(pwd)"
583.Ed
584.Pp
585Since
586.Nm
587changes the current working directory to
588.Sq Va .OBJDIR
589before executing any targets,
590each child process starts with that as its current working directory.
591.Sh VARIABLE ASSIGNMENTS
592Variables in make behave much like macros in the C preprocessor.
593.Pp
594Variable assignments have the form
595.Sq Ar NAME Ar op Ar value ,
596where:
597.Bl -tag -offset Ds -width Ds
598.It Ar NAME
599is a single-word variable name,
600consisting, by tradition, of all upper-case letters,
601.It Ar op
602is one of the variable assignment operators described below, and
603.It Ar value
604is interpreted according to the variable assignment operator.
605.El
606.Pp
607Whitespace around
608.Ar NAME ,
609.Ar op
610and
611.Ar value
612is discarded.
613.Ss Variable assignment operators
614The five operators that assign values to variables are:
615.Bl -tag -width Ds
616.It Ic \&=
617Assign the value to the variable.
618Any previous value is overwritten.
619.It Ic \&+=
620Append the value to the current value of the variable,
621separating them by a single space.
622.It Ic \&?=
623Assign the value to the variable if it is not already defined.
624.It Ic \&:=
625Expand the value, then assign it to the variable.
626.Pp
627.Em NOTE :
628References to undefined variables are
629.Em not
630expanded.
631This can cause problems when variable modifiers are used.
632.\" See var-op-expand.mk, the section with LATER and INDIRECT.
633.It Ic \&!=
634Expand the value and pass it to the shell for execution,
635then assign the output from the child's standard output to the variable.
636Any newlines in the result are replaced with spaces.
637.El
638.Ss Expansion of variables
639In most contexts where variables are expanded,
640.Ql \&$$
641expands to a single dollar sign.
642In other contexts (most variable modifiers, string literals in conditions),
643.Ql \&\e$
644expands to a single dollar sign.
645.Pp
646References to variables have the form
647.Cm \&${ Ns Ar name Ns Oo Ns Cm \&: Ns Ar modifiers Oc Ns Cm \&}
648or
649.Cm \&$( Ns Ar name Ns Oo Ns Cm \&: Ns Ar modifiers Oc Ns Cm \&) .
650If the variable name consists of only a single character
651and the expression contains no modifiers,
652the surrounding curly braces or parentheses are not required.
653This shorter form is not recommended.
654.Pp
655If the variable name contains a dollar, the name itself is expanded first.
656This allows almost arbitrary variable names, however names containing dollar,
657braces, parentheses or whitespace are really best avoided.
658.Pp
659If the result of expanding a nested variable expression contains a dollar sign
660.Pq Ql \&$ ,
661the result is subject to further expansion.
662.Pp
663Variable substitution occurs at four distinct times, depending on where
664the variable is being used.
665.Bl -enum
666.It
667Variables in dependency lines are expanded as the line is read.
668.It
669Variables in conditionals are expanded individually,
670but only as far as necessary to determine the result of the conditional.
671.It
672Variables in shell commands are expanded when the shell command is
673executed.
674.It
675.Ic .for
676loop index variables are expanded on each loop iteration.
677Note that other variables are not expanded when composing the body of a loop,
678so the following example code:
679.Bd -literal -offset indent
680\&.for i in 1 2 3
681a+=     ${i}
682j=      ${i}
683b+=     ${j}
684\&.endfor
685
686all:
687	@echo ${a}
688	@echo ${b}
689.Ed
690.Pp
691prints:
692.Bd -literal -offset indent
6931 2 3
6943 3 3
695.Ed
696.Pp
697After the loop is executed:
698.Bl -tag -offset indent -width indent
699.It Va a
700contains
701.Ql ${:U1} ${:U2} ${:U3} ,
702which expands to
703.Ql 1 2 3 .
704.It Va j
705contains
706.Ql ${:U3} ,
707which expands to
708.Ql 3 .
709.It Va b
710contains
711.Ql ${j} ${j} ${j} ,
712which expands to
713.Ql ${:U3} ${:U3} ${:U3}
714and further to
715.Ql 3 3 3 .
716.El
717.El
718.Ss Variable classes
719The four different classes of variables (in order of increasing precedence)
720are:
721.Bl -tag -width Ds
722.It Environment variables
723Variables defined as part of
724.Nm Ns 's
725environment.
726.It Global variables
727Variables defined in the makefile or in included makefiles.
728.It Command line variables
729Variables defined as part of the command line.
730.It Local variables
731Variables that are defined specific to a certain target.
732.El
733.Pp
734Local variables can be set on a dependency line, unless
735.Va .MAKE.TARGET_LOCAL_VARIABLES
736is set to
737.Ql false .
738The rest of the line
739(which already has had global variables expanded)
740is the variable value.
741For example:
742.Bd -literal -offset indent
743COMPILER_WRAPPERS= ccache distcc icecc
744
745${OBJS}: .MAKE.META.CMP_FILTER=${COMPILER_WRAPPERS:S,^,N,}
746.Ed
747.Pp
748Only the targets
749.Ql ${OBJS}
750are impacted by that filter (in
751.Dq meta
752mode) and
753simply enabling/disabling any of the compiler wrappers does not render all
754of those targets out-of-date.
755.Pp
756.Em NOTE :
757target-local variable assignments behave differently in that;
758.Bl -tag -width Ds -offset indent
759.It Ic \&+=
760Only appends to a previous local assignment
761for the same target and variable.
762.It Ic \&:=
763Is redundant with respect to global variables,
764which have already been expanded.
765.El
766.Pp
767The seven built-in local variables are:
768.Bl -tag -width ".Va .ARCHIVE" -offset indent
769.It Va .ALLSRC
770The list of all sources for this target; also known as
771.Sq Va \&> .
772.It Va .ARCHIVE
773The name of the archive file; also known as
774.Sq Va \&! .
775.It Va .IMPSRC
776In suffix-transformation rules, the name/path of the source from which the
777target is to be transformed (the
778.Dq implied
779source); also known as
780.Sq Va \&< .
781It is not defined in explicit rules.
782.It Va .MEMBER
783The name of the archive member; also known as
784.Sq Va % .
785.It Va .OODATE
786The list of sources for this target that were deemed out-of-date; also
787known as
788.Sq Va \&? .
789.It Va .PREFIX
790The file prefix of the target, containing only the file portion, no suffix
791or preceding directory components; also known as
792.Sq Va * .
793The suffix must be one of the known suffixes declared with
794.Ic .SUFFIXES ,
795or it is not recognized.
796.It Va .TARGET
797The name of the target; also known as
798.Sq Va @ .
799For compatibility with other makes this is an alias for
800.Va .ARCHIVE
801in archive member rules.
802.El
803.Pp
804The shorter forms
805.Po
806.Sq Va \&> ,
807.Sq Va \&! ,
808.Sq Va \&< ,
809.Sq Va \&% ,
810.Sq Va \&? ,
811.Sq Va \&* ,
812and
813.Sq Va \&@
814.Pc
815are permitted for backward
816compatibility with historical makefiles and legacy POSIX make and are
817not recommended.
818.Pp
819Variants of these variables with the punctuation followed immediately by
820.Ql D
821or
822.Ql F ,
823e.g.\&
824.Ql $(@D) ,
825are legacy forms equivalent to using the
826.Ql :H
827and
828.Ql :T
829modifiers.
830These forms are accepted for compatibility with
831.At V
832makefiles and POSIX but are not recommended.
833.Pp
834Four of the local variables may be used in sources on dependency lines
835because they expand to the proper value for each target on the line.
836These variables are
837.Sq Va .TARGET ,
838.Sq Va .PREFIX ,
839.Sq Va .ARCHIVE ,
840and
841.Sq Va .MEMBER .
842.Ss Additional built-in variables
843In addition,
844.Nm
845sets or knows about the following variables:
846.Bl -tag
847.\" NB: This list is sorted case-insensitive, ignoring punctuation.
848.\" NB: To find all built-in variables in make's source code,
849.\" NB: search for Var_*, Global_*, SetVarObjdir, GetBooleanExpr,
850.\" NB: and the implementation of Var_SetWithFlags.
851.\" NB: Last synced on 2023-01-01.
852.It Va .ALLTARGETS
853The list of all targets encountered in the makefiles.
854If evaluated during makefile parsing,
855lists only those targets encountered thus far.
856.It Va .CURDIR
857A path to the directory where
858.Nm
859was executed.
860Refer to the description of
861.Sq Va PWD
862for more details.
863.It Va .ERROR_CMD
864Is used in error handling, see
865.Va MAKE_PRINT_VAR_ON_ERROR .
866.It Va .ERROR_CWD
867Is used in error handling, see
868.Va MAKE_PRINT_VAR_ON_ERROR .
869.It Va .ERROR_META_FILE
870Is used in error handling in
871.Dq meta
872mode, see
873.Va MAKE_PRINT_VAR_ON_ERROR .
874.It Va .ERROR_TARGET
875Is used in error handling, see
876.Va MAKE_PRINT_VAR_ON_ERROR .
877.It Va .INCLUDEDFROMDIR
878The directory of the file this makefile was included from.
879.It Va .INCLUDEDFROMFILE
880The filename of the file this makefile was included from.
881.\" .INCLUDES is intentionally undocumented, as it is obsolete.
882.\" .LIBS is intentionally undocumented, as it is obsolete.
883.It Va MACHINE
884The machine hardware name, see
885.Xr uname 1 .
886.It Va MACHINE_ARCH
887The machine processor architecture name, see
888.Xr uname 1 .
889.It Va MAKE
890The name that
891.Nm
892was executed with
893.Pq Va argv[0] .
894.It Va .MAKE
895The same as
896.Va MAKE ,
897for compatibility.
898The preferred variable to use is the environment variable
899.Ev MAKE
900because it is more compatible with other make variants
901and cannot be confused with the special target with the same name.
902.\" '.MAKE.cmd_filtered' is intentionally undocumented,
903.\" as it is an internal implementation detail.
904.It Va .MAKE.DEPENDFILE
905Names the makefile (default
906.Sq Pa .depend )
907from which generated dependencies are read.
908.It Va .MAKE.DIE_QUIETLY
909If set to
910.Ql true ,
911do not print error information at the end.
912.It Va .MAKE.EXPAND_VARIABLES
913A boolean that controls the default behavior of the
914.Fl V
915option.
916If true, variable values printed with
917.Fl V
918are fully expanded; if false, the raw variable contents (which may
919include additional unexpanded variable references) are shown.
920.It Va .MAKE.EXPORTED
921The list of variables exported by
922.Nm .
923.It Va MAKEFILE
924The top-level makefile that is currently read,
925as given in the command line.
926.It Va .MAKEFLAGS
927The environment variable
928.Sq Ev MAKEFLAGS
929may contain anything that
930may be specified on
931.Nm Ns 's
932command line.
933Anything specified on
934.Nm Ns 's
935command line is appended to the
936.Va .MAKEFLAGS
937variable, which is then added to the environment for all programs that
938.Nm
939executes.
940.It Va .MAKE.GID
941The numeric group ID of the user running
942.Nm .
943It is read-only.
944.It Va .MAKE.JOB.PREFIX
945If
946.Nm
947is run with
948.Fl j ,
949the output for each target is prefixed with a token
950.Dl --- Ar target Li ---
951the first part of which can be controlled via
952.Va .MAKE.JOB.PREFIX .
953If
954.Va .MAKE.JOB.PREFIX
955is empty, no token is printed.
956For example, setting
957.Va .MAKE.JOB.PREFIX
958to
959.Ql ${.newline}---${.MAKE:T}[${.MAKE.PID}]
960would produce tokens like
961.Dl ---make[1234] Ar target Li ---
962making it easier to track the degree of parallelism being achieved.
963.It Va .MAKE.JOBS
964The argument to the
965.Fl j
966option.
967.It Va .MAKE.LEVEL
968The recursion depth of
969.Nm .
970The top-level instance of
971.Nm
972has level 0, and each child make has its parent level plus 1.
973This allows tests like:
974.Li .if ${.MAKE.LEVEL} == 0
975to protect things which should only be evaluated in the top-level instance of
976.Nm .
977.It Va .MAKE.LEVEL.ENV
978The name of the environment variable that stores the level of nested calls to
979.Nm .
980.It Va .MAKE.MAKEFILE_PREFERENCE
981The ordered list of makefile names
982(default
983.Sq Pa makefile ,
984.Sq Pa Makefile )
985that
986.Nm
987looks for.
988.It Va .MAKE.MAKEFILES
989The list of makefiles read by
990.Nm ,
991which is useful for tracking dependencies.
992Each makefile is recorded only once, regardless of the number of times read.
993.It Va .MAKE.META.BAILIWICK
994In
995.Dq meta
996mode, provides a list of prefixes which
997match the directories controlled by
998.Nm .
999If a file that was generated outside of
1000.Va .OBJDIR
1001but within said bailiwick is missing,
1002the current target is considered out-of-date.
1003.It Va .MAKE.META.CMP_FILTER
1004In
1005.Dq meta
1006mode, it can (very rarely!) be useful to filter command
1007lines before comparison.
1008This variable can be set to a set of modifiers that are applied to
1009each line of the old and new command that differ, if the filtered
1010commands still differ, the target is considered out-of-date.
1011.It Va .MAKE.META.CREATED
1012In
1013.Dq meta
1014mode, this variable contains a list of all the meta files
1015updated.
1016If not empty, it can be used to trigger processing of
1017.Va .MAKE.META.FILES .
1018.It Va .MAKE.META.FILES
1019In
1020.Dq meta
1021mode, this variable contains a list of all the meta files
1022used (updated or not).
1023This list can be used to process the meta files to extract dependency
1024information.
1025.It Va .MAKE.META.IGNORE_FILTER
1026Provides a list of variable modifiers to apply to each pathname.
1027Ignore if the expansion is an empty string.
1028.It Va .MAKE.META.IGNORE_PATHS
1029Provides a list of path prefixes that should be ignored;
1030because the contents are expected to change over time.
1031The default list includes:
1032.Sq Pa /dev /etc /proc /tmp /var/run /var/tmp
1033.It Va .MAKE.META.IGNORE_PATTERNS
1034Provides a list of patterns to match against pathnames.
1035Ignore any that match.
1036.It Va .MAKE.META.PREFIX
1037Defines the message printed for each meta file updated in
1038.Dq meta verbose
1039mode.
1040The default value is:
1041.Dl Building ${.TARGET:H:tA}/${.TARGET:T}
1042.It Va .MAKE.MODE
1043Processed after reading all makefiles.
1044Affects the mode that
1045.Nm
1046runs in.
1047It can contain these keywords:
1048.Bl -tag -width indent
1049.It Cm compat
1050Like
1051.Fl B ,
1052puts
1053.Nm
1054into
1055.Dq compat
1056mode.
1057.It Cm meta
1058Puts
1059.Nm
1060into
1061.Dq meta
1062mode, where meta files are created for each target
1063to capture the command run, the output generated, and if
1064.Xr filemon 4
1065is available, the system calls which are of interest to
1066.Nm .
1067The captured output can be useful when diagnosing errors.
1068.It Cm curdirOk= Ns Ar bf
1069By default,
1070.Nm
1071does not create
1072.Pa .meta
1073files in
1074.Sq Va .CURDIR .
1075This can be overridden by setting
1076.Ar bf
1077to a value which represents true.
1078.It Cm missing-meta= Ns Ar bf
1079If
1080.Ar bf
1081is true, a missing
1082.Pa .meta
1083file makes the target out-of-date.
1084.It Cm missing-filemon= Ns Ar bf
1085If
1086.Ar bf
1087is true, missing filemon data makes the target out-of-date.
1088.It Cm nofilemon
1089Do not use
1090.Xr filemon 4 .
1091.It Cm env
1092For debugging, it can be useful to include the environment
1093in the
1094.Pa .meta
1095file.
1096.It Cm verbose
1097If in
1098.Dq meta
1099mode, print a clue about the target being built.
1100This is useful if the build is otherwise running silently.
1101The message printed is the expanded value of
1102.Va .MAKE.META.PREFIX .
1103.It Cm ignore-cmd
1104Some makefiles have commands which are simply not stable.
1105This keyword causes them to be ignored for
1106determining whether a target is out of date in
1107.Dq meta
1108mode.
1109See also
1110.Ic .NOMETA_CMP .
1111.It Cm silent= Ns Ar bf
1112If
1113.Ar bf
1114is true, when a .meta file is created, mark the target
1115.Ic .SILENT .
1116.It Cm randomize-targets
1117In both compat and parallel mode, do not make the targets in the usual order,
1118but instead randomize their order.
1119This mode can be used to detect undeclared dependencies between files.
1120.El
1121.It Va MAKEOBJDIR
1122Used to create files in a separate directory, see
1123.Va .OBJDIR .
1124.It Va MAKE_OBJDIR_CHECK_WRITABLE
1125Used to force a separate directory for the created files,
1126even if that directory is not writable, see
1127.Va .OBJDIR .
1128.It Va MAKEOBJDIRPREFIX
1129Used to create files in a separate directory, see
1130.Va .OBJDIR .
1131.It Va .MAKE.OS
1132The name of the operating system, see
1133.Xr uname 1 .
1134It is read-only.
1135.It Va .MAKEOVERRIDES
1136This variable is used to record the names of variables assigned to
1137on the command line, so that they may be exported as part of
1138.Sq Ev MAKEFLAGS .
1139This behavior can be disabled by assigning an empty value to
1140.Sq Va .MAKEOVERRIDES
1141within a makefile.
1142Extra variables can be exported from a makefile
1143by appending their names to
1144.Sq Va .MAKEOVERRIDES .
1145.Sq Ev MAKEFLAGS
1146is re-exported whenever
1147.Sq Va .MAKEOVERRIDES
1148is modified.
1149.It Va .MAKE.PATH_FILEMON
1150If
1151.Nm
1152was built with
1153.Xr filemon 4
1154support, this is set to the path of the device node.
1155This allows makefiles to test for this support.
1156.It Va .MAKE.PID
1157The process ID of
1158.Nm .
1159It is read-only.
1160.It Va .MAKE.PPID
1161The parent process ID of
1162.Nm .
1163It is read-only.
1164.It Va MAKE_PRINT_VAR_ON_ERROR
1165When
1166.Nm
1167stops due to an error, it sets
1168.Sq Va .ERROR_TARGET
1169to the name of the target that failed,
1170.Sq Va .ERROR_CMD
1171to the commands of the failed target,
1172and in
1173.Dq meta
1174mode, it also sets
1175.Sq Va .ERROR_CWD
1176to the
1177.Xr getcwd 3 ,
1178and
1179.Sq Va .ERROR_META_FILE
1180to the path of the meta file (if any) describing the failed target.
1181It then prints its name and the value of
1182.Sq Va .CURDIR
1183as well as the value of any variables named in
1184.Sq Va MAKE_PRINT_VAR_ON_ERROR .
1185.It Va .MAKE.SAVE_DOLLARS
1186If true,
1187.Ql $$
1188are preserved when doing
1189.Ql :=
1190assignments.
1191The default is false, for backwards compatibility.
1192Set to true for compatability with other makes.
1193If set to false,
1194.Ql $$
1195becomes
1196.Ql $
1197per normal evaluation rules.
1198.It Va .MAKE.TARGET_LOCAL_VARIABLES
1199If set to
1200.Ql false ,
1201apparent variable assignments in dependency lines are
1202treated as normal sources.
1203.It Va .MAKE.UID
1204The numeric ID of the user running
1205.Nm .
1206It is read-only.
1207.\" 'MAKE_VERSION' is intentionally undocumented
1208.\" since it is only defined in the bmake distribution,
1209.\" but not in NetBSD's native make.
1210.\" '.meta.%d.lcwd' is intentionally undocumented
1211.\" since it is an internal implementation detail.
1212.\" '.meta.%d.ldir' is intentionally undocumented
1213.\" since it is an internal implementation detail.
1214.\" 'MFLAGS' is intentionally undocumented
1215.\" since it is obsolete.
1216.It Va .newline
1217This variable is simply assigned a newline character as its value.
1218It is read-only.
1219This allows expansions using the
1220.Cm \&:@
1221modifier to put a newline between
1222iterations of the loop rather than a space.
1223For example, in case of an error,
1224.Nm
1225prints the variable names and their values using:
1226.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1227.It Va .OBJDIR
1228A path to the directory where the targets are built.
1229Its value is determined by trying to
1230.Xr chdir 2
1231to the following directories in order and using the first match:
1232.Bl -enum
1233.It
1234.Cm ${MAKEOBJDIRPREFIX} Ns Cm ${.CURDIR}
1235.Pp
1236(Only if
1237.Sq Ev MAKEOBJDIRPREFIX
1238is set in the environment or on the command line.)
1239.It
1240.Cm ${MAKEOBJDIR}
1241.Pp
1242(Only if
1243.Sq Ev MAKEOBJDIR
1244is set in the environment or on the command line.)
1245.It
1246.Cm ${.CURDIR} Ns Pa /obj. Ns Cm ${MACHINE}
1247.It
1248.Cm ${.CURDIR} Ns Pa /obj
1249.It
1250.Pa /usr/obj/ Ns Cm ${.CURDIR}
1251.It
1252.Cm ${.CURDIR}
1253.El
1254.Pp
1255Variable expansion is performed on the value before it is used,
1256so expressions such as
1257.Cm ${.CURDIR:S,^/usr/src,/var/obj,}
1258may be used.
1259This is especially useful with
1260.Sq Ev MAKEOBJDIR .
1261.Pp
1262.Sq Va .OBJDIR
1263may be modified in the makefile via the special target
1264.Sq Ic .OBJDIR .
1265In all cases,
1266.Nm
1267changes to the specified directory if it exists, and sets
1268.Sq Va .OBJDIR
1269and
1270.Sq Va PWD
1271to that directory before executing any targets.
1272.Pp
1273Except in the case of an explicit
1274.Sq Ic .OBJDIR
1275target,
1276.Nm
1277checks that the specified directory is writable and ignores it if not.
1278This check can be skipped by setting the environment variable
1279.Sq Ev MAKE_OBJDIR_CHECK_WRITABLE
1280to
1281.Dq no .
1282.It Va .PARSEDIR
1283The directory name of the current makefile being parsed.
1284.It Va .PARSEFILE
1285The basename of the current makefile being parsed.
1286This variable and
1287.Sq Va .PARSEDIR
1288are both set only while the makefiles are being parsed.
1289To retain their current values,
1290assign them to a variable using assignment with expansion
1291.Sq Cm \&:= .
1292.It Va .PATH
1293The space-separated list of directories that
1294.Nm
1295searches for files.
1296To update this search list, use the special target
1297.Sq Ic .PATH
1298rather than modifying the variable directly.
1299.It Va %POSIX
1300Is set in POSIX mode, see the special
1301.Ql Va .POSIX
1302target.
1303.\" XXX: There is no make variable named 'PWD',
1304.\" XXX: make only reads and writes the environment variable 'PWD'.
1305.It Va PWD
1306Alternate path to the current directory.
1307.Nm
1308normally sets
1309.Sq Va .CURDIR
1310to the canonical path given by
1311.Xr getcwd 3 .
1312However, if the environment variable
1313.Sq Ev PWD
1314is set and gives a path to the current directory,
1315.Nm
1316sets
1317.Sq Va .CURDIR
1318to the value of
1319.Sq Ev PWD
1320instead.
1321This behavior is disabled if
1322.Sq Ev MAKEOBJDIRPREFIX
1323is set or
1324.Sq Ev MAKEOBJDIR
1325contains a variable transform.
1326.Sq Va PWD
1327is set to the value of
1328.Sq Va .OBJDIR
1329for all programs which
1330.Nm
1331executes.
1332.It Va .SHELL
1333The pathname of the shell used to run target scripts.
1334It is read-only.
1335.It Va .SUFFIXES
1336The list of known suffixes.
1337It is read-only.
1338.It Va .SYSPATH
1339The space-separated list of directories that
1340.Nm
1341searches for makefiles, referred to as the system include path.
1342To update this search list, use the special target
1343.Sq Ic .SYSPATH
1344rather than modifying the variable which is read-only.
1345.It Va .TARGETS
1346The list of targets explicitly specified on the command line, if any.
1347.It Va VPATH
1348The colon-separated
1349.Pq Dq \&:
1350list of directories that
1351.Nm
1352searches for files.
1353This variable is supported for compatibility with old make programs only, use
1354.Sq Va .PATH
1355instead.
1356.El
1357.Ss Variable modifiers
1358The general format of a variable expansion is:
1359.Pp
1360.Sm off
1361.D1 Ic \&${ Ar variable\| Oo Ic \&: Ar modifier\| Oo Ic \&: No ... Oc Oc Ic \&}
1362.Sm on
1363.Pp
1364Each modifier begins with a colon.
1365To escape a colon, precede it with a backslash
1366.Ql \e .
1367.Pp
1368A list of indirect modifiers can be specified via a variable, as follows:
1369.Pp
1370.Bd -literal -offset indent
1371.Ar modifier_variable\^ Li \&= Ar modifier Ns Oo Ic \&: Ns No ... Oc
1372
1373.Sm off
1374.Ic \&${ Ar variable Ic \&:${ Ar modifier_variable Ic \&} Oo Ic \&: No ... Oc Ic \&}
1375.Sm on
1376.Ed
1377.Pp
1378In this case, the first modifier in the
1379.Ar modifier_variable
1380does not start with a colon,
1381since that colon already occurs in the referencing variable.
1382If any of the modifiers in the
1383.Ar modifier_variable
1384contains a dollar sign
1385.Pq Ql $ ,
1386these must be doubled to avoid early expansion.
1387.Pp
1388Some modifiers interpret the expression value as a single string,
1389others treat the expression value as a whitespace-separated list of words.
1390When splitting a string into words,
1391whitespace can be escaped using double quotes, single quotes and backslashes,
1392like in the shell.
1393The quotes and backslashes are retained in the words.
1394.Pp
1395The supported modifiers are:
1396.Bl -tag -width EEE
1397.It Cm \&:E
1398Replaces each word with its suffix.
1399.It Cm \&:H
1400Replaces each word with its dirname.
1401.It Cm \&:M\| Ns Ar pattern
1402Selects only those words that match
1403.Ar pattern .
1404The standard shell wildcard characters
1405.Pf ( Ql * ,
1406.Ql \&? ,
1407and
1408.Ql \&[] )
1409may
1410be used.
1411The wildcard characters may be escaped with a backslash
1412.Pq Ql \e .
1413As a consequence of the way values are split into words, matched,
1414and then joined, the construct
1415.Ql ${VAR:M*}
1416removes all leading and trailing whitespace
1417and normalizes the inter-word spacing to a single space.
1418.It Cm \&:N\| Ns Ar pattern
1419This is the opposite of
1420.Sq Cm \&:M ,
1421selecting all words which do
1422.Em not
1423match
1424.Ar pattern .
1425.It Cm \&:O
1426Orders the words lexicographically.
1427.It Cm \&:On
1428Orders the words numerically.
1429A number followed by one of
1430.Ql k ,
1431.Ql M
1432or
1433.Ql G
1434is multiplied by the appropriate factor, which is 1024 for
1435.Ql k ,
14361048576 for
1437.Ql M ,
1438or 1073741824 for
1439.Ql G .
1440Both upper- and lower-case letters are accepted.
1441.It Cm \&:Or
1442Orders the words in reverse lexicographical order.
1443.It Cm \&:Orn
1444Orders the words in reverse numerical order.
1445.It Cm \&:Ox
1446Shuffles the words.
1447The results are different each time you are referring to the
1448modified variable; use the assignment with expansion
1449.Sq Cm \&:=
1450to prevent such behavior.
1451For example,
1452.Bd -literal -offset indent
1453LIST=			uno due tre quattro
1454RANDOM_LIST=		${LIST:Ox}
1455STATIC_RANDOM_LIST:=	${LIST:Ox}
1456
1457all:
1458	@echo "${RANDOM_LIST}"
1459	@echo "${RANDOM_LIST}"
1460	@echo "${STATIC_RANDOM_LIST}"
1461	@echo "${STATIC_RANDOM_LIST}"
1462.Ed
1463may produce output similar to:
1464.Bd -literal -offset indent
1465quattro due tre uno
1466tre due quattro uno
1467due uno quattro tre
1468due uno quattro tre
1469.Ed
1470.It Cm \&:Q
1471Quotes every shell meta-character in the value, so that it can be passed
1472safely to the shell.
1473.It Cm \&:q
1474Quotes every shell meta-character in the value, and also doubles
1475.Sq $
1476characters so that it can be passed
1477safely through recursive invocations of
1478.Nm .
1479This is equivalent to
1480.Sq Cm \&:S/\e\&$/&&/g:Q .
1481.It Cm \&:R
1482Replaces each word with everything but its suffix.
1483.It Cm \&:range Ns Oo Cm = Ns Ar count Oc
1484The value is an integer sequence representing the words of the original
1485value, or the supplied
1486.Ar count .
1487.It Cm \&:gmtime Ns Oo Cm = Ns Ar timestamp Oc
1488The value is interpreted as a format string for
1489.Xr strftime 3 ,
1490using
1491.Xr gmtime 3 ,
1492producing the formatted timestamp.
1493If a
1494.Ar timestamp
1495value is not provided or is 0, the current time is used.
1496.It Cm \&:hash
1497Computes a 32-bit hash of the value and encodes it as 8 hex digits.
1498.It Cm \&:localtime Ns Oo Cm = Ns Ar timestamp Oc
1499The value is interpreted as a format string for
1500.Xr strftime 3 ,
1501using
1502.Xr localtime 3 ,
1503producing the formatted timestamp.
1504If a
1505.Ar timestamp
1506value is not provided or is 0, the current time is used.
1507.It Cm \&:tA
1508Attempts to convert the value to an absolute path using
1509.Xr realpath 3 .
1510If that fails, the value is unchanged.
1511.It Cm \&:tl
1512Converts the value to lower-case letters.
1513.It Cm \&:ts Ns Ar c
1514When joining the words after a modifier that treats the value as words,
1515the words are normally separated by a space.
1516This modifier changes the separator to the character
1517.Ar c .
1518If
1519.Ar c
1520is omitted, no separator is used.
1521The common escapes (including octal numeric codes) work as expected.
1522.It Cm \&:tu
1523Converts the value to upper-case letters.
1524.It Cm \&:tW
1525Causes subsequent modifiers to treat the value as a single word
1526(possibly containing embedded whitespace).
1527See also
1528.Sq Cm \&:[*] .
1529.It Cm \&:tw
1530Causes the value to be treated as a list of words.
1531See also
1532.Sq Cm \&:[@] .
1533.Sm off
1534.It Cm \&:S\| No \&/ Ar old_string\| No \&/ Ar new_string\| No \&/ Op Cm 1gW
1535.Sm on
1536Modifies the first occurrence of
1537.Ar old_string
1538in each word of the value, replacing it with
1539.Ar new_string .
1540If a
1541.Ql g
1542is appended to the last delimiter of the pattern,
1543all occurrences in each word are replaced.
1544If a
1545.Ql 1
1546is appended to the last delimiter of the pattern,
1547only the first occurrence is affected.
1548If a
1549.Ql W
1550is appended to the last delimiter of the pattern,
1551the value is treated as a single word.
1552If
1553.Ar old_string
1554begins with a caret
1555.Pq Ql ^ ,
1556.Ar old_string
1557is anchored at the beginning of each word.
1558If
1559.Ar old_string
1560ends with a dollar sign
1561.Pq Ql \&$ ,
1562it is anchored at the end of each word.
1563Inside
1564.Ar new_string ,
1565an ampersand
1566.Pq Ql &
1567is replaced by
1568.Ar old_string
1569(without the anchoring
1570.Ql ^
1571or
1572.Ql \&$ ) .
1573Any character may be used as the delimiter for the parts of the modifier
1574string.
1575The anchoring, ampersand and delimiter characters can be escaped with a
1576backslash
1577.Pq Ql \e .
1578.Pp
1579Both
1580.Ar old_string
1581and
1582.Ar new_string
1583may contain nested expressions.
1584To prevent a dollar sign from starting a nested expression,
1585escape it with a backslash.
1586.Sm off
1587.It Cm \&:C\| No \&/ Ar pattern\| No \&/ Ar replacement\| No \&/ Op Cm 1gW
1588.Sm on
1589The
1590.Cm \&:C
1591modifier works like the
1592.Cm \&:S
1593modifier except that the old and new strings, instead of being
1594simple strings, are an extended regular expression
1595.Ar pattern
1596(see
1597.Xr regex 3 )
1598and an
1599.Xr ed 1 Ns \-style
1600.Ar replacement .
1601Normally, the first occurrence of the pattern
1602.Ar pattern
1603in each word of the value is substituted with
1604.Ar replacement .
1605The
1606.Ql 1
1607modifier causes the substitution to apply to at most one word; the
1608.Ql g
1609modifier causes the substitution to apply to as many instances of the
1610search pattern
1611.Ar pattern
1612as occur in the word or words it is found in; the
1613.Ql W
1614modifier causes the value to be treated as a single word
1615(possibly containing embedded whitespace).
1616.Pp
1617As for the
1618.Cm \&:S
1619modifier, the
1620.Ar pattern
1621and
1622.Ar replacement
1623are subjected to variable expansion before being parsed as
1624regular expressions.
1625.It Cm \&:T
1626Replaces each word with its last path component (basename).
1627.It Cm \&:u
1628Removes adjacent duplicate words (like
1629.Xr uniq 1 ) .
1630.Sm off
1631.It Cm \&:\&?\| Ar true_string\| Cm \&: Ar false_string
1632.Sm on
1633If the variable name (not its value), when parsed as a
1634.Cm .if
1635conditional expression, evaluates to true, return as its value the
1636.Ar true_string ,
1637otherwise return the
1638.Ar false_string .
1639Since the variable name is used as the expression,
1640\&:\&? must be the first modifier after the variable name
1641.No itself Ns \^\(em\^ Ns
1642which, of course, usually contains variable expansions.
1643A common error is trying to use expressions like
1644.Dl ${NUMBERS:M42:?match:no}
1645which actually tests defined(NUMBERS).
1646To determine if any words match
1647.Dq 42 ,
1648you need to use something like:
1649.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1650.It Cm :\| Ns Ar old_string\| Ns Cm = Ns Ar new_string
1651This is the
1652.At V
1653style substitution.
1654It can only be the last modifier specified,
1655as a
1656.Ql \&:
1657in either
1658.Ar old_string
1659or
1660.Ar new_string
1661is treated as a regular character, not as the end of the modifier.
1662.Pp
1663If
1664.Ar old_string
1665does not contain the pattern matching character
1666.Ql % ,
1667and the word ends with
1668.Ar old_string
1669or equals it,
1670that suffix is replaced with
1671.Ar new_string .
1672.Pp
1673Otherwise, the first
1674.Ql %
1675in
1676.Ar old_string
1677matches a possibly empty substring of arbitrary characters,
1678and if the whole pattern is found in the word,
1679the matching part is replaced with
1680.Ar new_string ,
1681and the first occurrence of
1682.Ql %
1683in
1684.Ar new_string
1685(if any) is replaced with the substring matched by the
1686.Ql % .
1687.Pp
1688Both
1689.Ar old_string
1690and
1691.Ar new_string
1692may contain nested expressions.
1693To prevent a dollar sign from starting a nested expression,
1694escape it with a backslash.
1695.Sm off
1696.It Cm \&:@ Ar varname\| Cm @ Ar string\| Cm @
1697.Sm on
1698This is the loop expansion mechanism from the OSF Development
1699Environment (ODE) make.
1700Unlike
1701.Cm \&.for
1702loops, expansion occurs at the time of reference.
1703For each word in the value, assign the word to the variable named
1704.Ar varname
1705and evaluate
1706.Ar string .
1707The ODE convention is that
1708.Ar varname
1709should start and end with a period, for example:
1710.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1711.Pp
1712However, a single-letter variable is often more readable:
1713.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1714.It Cm \&:_ Ns Oo Cm = Ns Ar var Oc
1715Saves the current variable value in
1716.Ql $_
1717or the named
1718.Ar var
1719for later reference.
1720Example usage:
1721.Bd -literal -offset indent
1722M_cmpv.units = 1 1000 1000000
1723M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\
1724\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh
1725
1726.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}
1727
1728.Ed
1729Here
1730.Ql $_
1731is used to save the result of the
1732.Ql :S
1733modifier which is later referenced using the index values from
1734.Ql :range .
1735.It Cm \&:U\| Ns Ar newval
1736If the variable is undefined,
1737.Ar newval
1738is the value.
1739If the variable is defined, the existing value is returned.
1740This is another ODE make feature.
1741It is handy for setting per-target CFLAGS for instance:
1742.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1743If a value is only required if the variable is undefined, use:
1744.Dl ${VAR:D:Unewval}
1745.It Cm \&:D\| Ns Ar newval
1746If the variable is defined,
1747.Ar newval
1748is the value.
1749.It Cm \&:L
1750The name of the variable is the value.
1751.It Cm \&:P
1752The path of the node which has the same name as the variable is the value.
1753If no such node exists or its path is null, the name of the variable is used.
1754In order for this modifier to work, the name (node) must at least have
1755appeared on the right-hand side of a dependency.
1756.Sm off
1757.It Cm \&:\&! Ar cmd\| Cm \&!
1758.Sm on
1759The output of running
1760.Ar cmd
1761is the value.
1762.It Cm \&:sh
1763The value is run as a command, and the output becomes the new value.
1764.It Cm \&::= Ns Ar str
1765The variable is assigned the value
1766.Ar str
1767after substitution.
1768This modifier and its variations are useful in obscure situations
1769such as wanting to set a variable
1770at a point where a target's shell commands are being parsed.
1771These assignment modifiers always expand to nothing.
1772.Pp
1773The
1774.Sq Cm \&::
1775helps avoid false matches with the
1776.At V
1777style
1778.Ql \&:=
1779modifier and since substitution always occurs, the
1780.Ql \&::=
1781form is vaguely appropriate.
1782.It Cm \&::?= Ns Ar str
1783As for
1784.Cm \&::=
1785but only if the variable does not already have a value.
1786.It Cm \&::+= Ns Ar str
1787Append
1788.Ar str
1789to the variable.
1790.It Cm \&::!= Ns Ar cmd
1791Assign the output of
1792.Ar cmd
1793to the variable.
1794.It Cm \&:\&[ Ns Ar range Ns Cm \&]
1795Selects one or more words from the value,
1796or performs other operations related to the way in which the
1797value is split into words.
1798.Pp
1799An empty value, or a value that consists entirely of white-space,
1800is treated as a single word.
1801For the purposes of the
1802.Sq Cm \&:[]
1803modifier, the words are indexed both forwards using positive integers
1804(where index 1 represents the first word),
1805and backwards using negative integers
1806(where index \-1 represents the last word).
1807.Pp
1808The
1809.Ar range
1810is subjected to variable expansion, and the expanded result is
1811then interpreted as follows:
1812.Bl -tag -width index
1813.\" :[n]
1814.It Ar index
1815Selects a single word from the value.
1816.\" :[start..end]
1817.It Ar start Ns Cm \&.. Ns Ar end
1818Selects all words from
1819.Ar start
1820to
1821.Ar end ,
1822inclusive.
1823For example,
1824.Sq Cm \&:[2..-1]
1825selects all words from the second word to the last word.
1826If
1827.Ar start
1828is greater than
1829.Ar end ,
1830the words are output in reverse order.
1831For example,
1832.Sq Cm \&:[-1..1]
1833selects all the words from last to first.
1834If the list is already ordered,
1835this effectively reverses the list,
1836but it is more efficient to use
1837.Sq Cm \&:Or
1838instead of
1839.Sq Cm \&:O:[-1..1] .
1840.\" :[*]
1841.It Cm \&*
1842Causes subsequent modifiers to treat the value as a single word
1843(possibly containing embedded whitespace).
1844Analogous to the effect of
1845.Li \&$*
1846in Bourne shell.
1847.\" :[0]
1848.It 0
1849Means the same as
1850.Sq Cm \&:[*] .
1851.\" :[*]
1852.It Cm \&@
1853Causes subsequent modifiers to treat the value as a sequence of words
1854delimited by whitespace.
1855Analogous to the effect of
1856.Li \&$@
1857in Bourne shell.
1858.\" :[#]
1859.It Cm \&#
1860Returns the number of words in the value.
1861.El \" :[range]
1862.El
1863.Sh DIRECTIVES
1864.Nm
1865offers directives for including makefiles, conditionals and for loops.
1866All these directives are identified by a line beginning with a single dot
1867.Pq Ql \&.
1868character, followed by the keyword of the directive, such as
1869.Cm include
1870or
1871.Cm if .
1872.Ss File inclusion
1873Files are included with either
1874.Cm \&.include \&< Ns Ar file Ns Cm \&>
1875or
1876.Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q .
1877Variables between the angle brackets or double quotes are expanded
1878to form the file name.
1879If angle brackets are used, the included makefile is expected to be in
1880the system makefile directory.
1881If double quotes are used, the including makefile's directory and any
1882directories specified using the
1883.Fl I
1884option are searched before the system makefile directory.
1885.Pp
1886For compatibility with other make variants,
1887.Sq Cm include Ar file No ...
1888(without leading dot)
1889is also accepted.
1890.Pp
1891If the include statement is written as
1892.Cm .-include
1893or as
1894.Cm .sinclude ,
1895errors locating and/or opening include files are ignored.
1896.Pp
1897If the include statement is written as
1898.Cm .dinclude ,
1899not only are errors locating and/or opening include files ignored,
1900but stale dependencies within the included file are ignored just like in
1901.Va .MAKE.DEPENDFILE .
1902.Ss Exporting variables
1903The directives for exporting and unexporting variables are:
1904.Bl -tag -width Ds
1905.It Ic .export Ar variable No ...
1906Export the specified global variable.
1907If no variable list is provided, all globals are exported
1908except for internal variables (those that start with
1909.Ql \&. ) .
1910This is not affected by the
1911.Fl X
1912flag, so should be used with caution.
1913For compatibility with other make programs,
1914.Cm export Ar variable\| Ns Cm \&= Ns Ar value
1915(without leading dot) is also accepted.
1916.Pp
1917Appending a variable name to
1918.Va .MAKE.EXPORTED
1919is equivalent to exporting a variable.
1920.It Ic .export-env Ar variable No ...
1921The same as
1922.Ql .export ,
1923except that the variable is not appended to
1924.Va .MAKE.EXPORTED .
1925This allows exporting a value to the environment which is different from that
1926used by
1927.Nm
1928internally.
1929.It Ic .export-literal Ar variable No ...
1930The same as
1931.Ql .export-env ,
1932except that variables in the value are not expanded.
1933.It Ic .unexport Ar variable No ...
1934The opposite of
1935.Ql .export .
1936The specified global
1937.Ar variable
1938is removed from
1939.Va .MAKE.EXPORTED .
1940If no variable list is provided, all globals are unexported,
1941and
1942.Va .MAKE.EXPORTED
1943deleted.
1944.It Ic .unexport-env
1945Unexport all globals previously exported and
1946clear the environment inherited from the parent.
1947This operation causes a memory leak of the original environment,
1948so should be used sparingly.
1949Testing for
1950.Va .MAKE.LEVEL
1951being 0 would make sense.
1952Also note that any variables which originated in the parent environment
1953should be explicitly preserved if desired.
1954For example:
1955.Bd -literal -offset indent
1956.Li .if ${.MAKE.LEVEL} == 0
1957PATH := ${PATH}
1958.Li .unexport-env
1959.Li .export PATH
1960.Li .endif
1961.Pp
1962.Ed
1963Would result in an environment containing only
1964.Sq Ev PATH ,
1965which is the minimal useful environment.
1966.\" TODO: Check the below sentence, environment variables don't start with '.'.
1967Actually
1968.Sq Va .MAKE.LEVEL
1969is also pushed into the new environment.
1970.El
1971.Ss Messages
1972The directives for printing messages to the output are:
1973.Bl -tag -width Ds
1974.It Ic .info Ar message
1975The message is printed along with the name of the makefile and line number.
1976.It Ic .warning Ar message
1977The message prefixed by
1978.Sq Li warning:
1979is printed along with the name of the makefile and line number.
1980.It Ic .error Ar message
1981The message is printed along with the name of the makefile and line number,
1982.Nm
1983exits immediately.
1984.El
1985.Ss Conditionals
1986The directives for conditionals are:
1987.ds maybenot Oo Ic \&! Oc Ns
1988.Bl -tag
1989.It Ic .if \*[maybenot] Ar expression Op Ar operator expression No ...
1990Test the value of an expression.
1991.It Ic .ifdef \*[maybenot] Ar variable Op Ar operator variable No ...
1992Test whether a variable is defined.
1993.It Ic .ifndef \*[maybenot] Ar variable Op Ar operator variable No ...
1994Test whether a variable is not defined.
1995.It Ic .ifmake \*[maybenot] Ar target Op Ar operator target No ...
1996Test the target being requested.
1997.It Ic .ifnmake \*[maybenot] Ar target Op Ar operator target No ...
1998Test the target being requested.
1999.It Ic .else
2000Reverse the sense of the last conditional.
2001.It Ic .elif \*[maybenot] Ar expression Op Ar operator expression No ...
2002A combination of
2003.Sq Ic .else
2004followed by
2005.Sq Ic .if .
2006.It Ic .elifdef \*[maybenot] Ar variable Op Ar operator variable No ...
2007A combination of
2008.Sq Ic .else
2009followed by
2010.Sq Ic .ifdef .
2011.It Ic .elifndef \*[maybenot] Ar variable Op Ar operator variable No ...
2012A combination of
2013.Sq Ic .else
2014followed by
2015.Sq Ic .ifndef .
2016.It Ic .elifmake \*[maybenot] Ar target Op Ar operator target No ...
2017A combination of
2018.Sq Ic .else
2019followed by
2020.Sq Ic .ifmake .
2021.It Ic .elifnmake \*[maybenot] Ar target Op Ar operator target No ...
2022A combination of
2023.Sq Ic .else
2024followed by
2025.Sq Ic .ifnmake .
2026.It Ic .endif
2027End the body of the conditional.
2028.El
2029.Pp
2030The
2031.Ar operator
2032may be any one of the following:
2033.Bl -tag
2034.It Ic \&|\&|
2035Logical OR.
2036.It Ic \&&&
2037Logical AND; of higher precedence than
2038.Sq Ic \&|\&| .
2039.El
2040.Pp
2041.Nm
2042only evaluates a conditional as far as is necessary to determine its value.
2043Parentheses can be used to override the operator precedence.
2044The boolean operator
2045.Sq Ic \&!
2046may be used to logically negate an entire conditional.
2047It is of higher precedence than
2048.Sq Ic \&&& .
2049.Pp
2050The value of
2051.Ar expression
2052may be any of the following function call expressions:
2053.Bl -tag
2054.Sm off
2055.It Ic defined Li \&( Ar varname Li \&)
2056.Sm on
2057Evaluates to true if the variable
2058.Ar varname
2059has been defined.
2060.Sm off
2061.It Ic make Li \&( Ar target Li \&)
2062.Sm on
2063Evaluates to true if the target was specified as part of
2064.Nm Ns 's
2065command line or was declared the default target (either implicitly or
2066explicitly, see
2067.Va .MAIN )
2068before the line containing the conditional.
2069.Sm off
2070.It Ic empty Li \&( Ar varname Oo Li : Ar modifiers Oc Li \&)
2071.Sm on
2072Evaluates to true if the expansion of the variable,
2073after applying the modifiers, results in an empty string.
2074.Sm off
2075.It Ic exists Li \&( Ar pathname Li \&)
2076.Sm on
2077Evaluates to true if the given pathname exists.
2078If relative, the pathname is searched for on the system search path (see
2079.Va .PATH ) .
2080.Sm off
2081.It Ic target Li \&( Ar target Li \&)
2082.Sm on
2083Evaluates to true if the target has been defined.
2084.Sm off
2085.It Ic commands Li \&( Ar target Li \&)
2086.Sm on
2087Evaluates to true if the target has been defined
2088and has commands associated with it.
2089.El
2090.Pp
2091.Ar Expression
2092may also be an arithmetic or string comparison.
2093Variable expansion is performed on both sides of the comparison.
2094If both sides are numeric and neither is enclosed in quotes,
2095the comparison is done numerically, otherwise lexicographically.
2096A string is interpreted as hexadecimal integer if it is preceded by
2097.Li 0x ,
2098otherwise it is a decimal floating-point number;
2099octal numbers are not supported.
2100.Pp
2101All comparisons may use the operators
2102.Sq Ic \&==
2103and
2104.Sq Ic \&!= .
2105Numeric comparisons may also use the operators
2106.Sq Ic \&< ,
2107.Sq Ic \&<= ,
2108.Sq Ic \&>
2109and
2110.Sq Ic \&>= .
2111.Pp
2112If the comparison has neither a comparison operator nor a right side,
2113the expression evaluates to true if it is nonempty
2114and its numeric value (if any) is not zero.
2115.Pp
2116When
2117.Nm
2118is evaluating one of these conditional expressions, and it encounters
2119a (whitespace separated) word it doesn't recognize, either the
2120.Dq make
2121or
2122.Dq defined
2123function is applied to it, depending on the form of the conditional.
2124If the form is
2125.Sq Ic .ifdef ,
2126.Sq Ic .ifndef
2127or
2128.Sq Ic .if ,
2129the
2130.Dq defined
2131function is applied.
2132Similarly, if the form is
2133.Sq Ic .ifmake
2134or
2135.Sq Ic .ifnmake ,
2136the
2137.Dq make
2138function is applied.
2139.Pp
2140If the conditional evaluates to true,
2141parsing of the makefile continues as before.
2142If it evaluates to false, the following lines are skipped.
2143In both cases, this continues until the corresponding
2144.Sq Ic .else
2145or
2146.Sq Ic .endif
2147is found.
2148.Ss For loops
2149For loops are typically used to apply a set of rules to a list of files.
2150The syntax of a for loop is:
2151.Pp
2152.Bl -tag -compact -width Ds
2153.It Ic \&.for Ar variable Oo Ar variable No ... Oc Ic in Ar expression
2154.It Aq Ar make-lines
2155.It Ic \&.endfor
2156.El
2157.Pp
2158The
2159.Ar expression
2160is expanded and then split into words.
2161On each iteration of the loop, one word is taken and assigned to each
2162.Ar variable ,
2163in order, and these
2164.Ar variables
2165are substituted into the
2166.Ar make-lines
2167inside the body of the for loop.
2168The number of words must come out even; that is, if there are three
2169iteration variables, the number of words provided must be a multiple
2170of three.
2171.Pp
2172If
2173.Sq Ic .break
2174is encountered within a
2175.Cm \&.for
2176loop, it causes early termination of the loop, otherwise a parse error.
2177.\" TODO: Describe limitations with defined/empty.
2178.Ss Other directives
2179.Bl -tag -width Ds
2180.It Ic .undef Ar variable No ...
2181Un-define the specified global variables.
2182Only global variables can be un-defined.
2183.El
2184.Sh COMMENTS
2185Comments begin with a hash
2186.Pq Ql \&#
2187character, anywhere but in a shell
2188command line, and continue to the end of an unescaped new line.
2189.Sh SPECIAL SOURCES (ATTRIBUTES)
2190.Bl -tag -width .IGNOREx
2191.It Ic .EXEC
2192Target is never out of date, but always execute commands anyway.
2193.It Ic .IGNORE
2194Ignore any errors from the commands associated with this target, exactly
2195as if they all were preceded by a dash
2196.Pq Ql \- .
2197.\" .It Ic .INVISIBLE
2198.\" XXX
2199.\" .It Ic .JOIN
2200.\" XXX
2201.It Ic .MADE
2202Mark all sources of this target as being up to date.
2203.It Ic .MAKE
2204Execute the commands associated with this target even if the
2205.Fl n
2206or
2207.Fl t
2208options were specified.
2209Normally used to mark recursive
2210.Nm Ns s .
2211.It Ic .META
2212Create a meta file for the target, even if it is flagged as
2213.Ic .PHONY ,
2214.Ic .MAKE ,
2215or
2216.Ic .SPECIAL .
2217Usage in conjunction with
2218.Ic .MAKE
2219is the most likely case.
2220In
2221.Dq meta
2222mode, the target is out-of-date if the meta file is missing.
2223.It Ic .NOMETA
2224Do not create a meta file for the target.
2225Meta files are also not created for
2226.Ic .PHONY ,
2227.Ic .MAKE ,
2228or
2229.Ic .SPECIAL
2230targets.
2231.It Ic .NOMETA_CMP
2232Ignore differences in commands when deciding if target is out of date.
2233This is useful if the command contains a value which always changes.
2234If the number of commands change, though,
2235the target is still considered out of date.
2236The same effect applies to any command line that uses the variable
2237.Va .OODATE ,
2238which can be used for that purpose even when not otherwise needed or desired:
2239.Bd -literal -offset indent
2240
2241skip-compare-for-some:
2242	@echo this is compared
2243	@echo this is not ${.OODATE:M.NOMETA_CMP}
2244	@echo this is also compared
2245
2246.Ed
2247The
2248.Cm \&:M
2249pattern suppresses any expansion of the unwanted variable.
2250.It Ic .NOPATH
2251Do not search for the target in the directories specified by
2252.Va .PATH .
2253.It Ic .NOTMAIN
2254Normally
2255.Nm
2256selects the first target it encounters as the default target to be built
2257if no target was specified.
2258This source prevents this target from being selected.
2259.It Ic .OPTIONAL
2260If a target is marked with this attribute and
2261.Nm
2262can't figure out how to create it, it ignores this fact and assumes
2263the file isn't needed or already exists.
2264.It Ic .PHONY
2265The target does not correspond to an actual file;
2266it is always considered to be out of date,
2267and is not created with the
2268.Fl t
2269option.
2270Suffix-transformation rules are not applied to
2271.Ic .PHONY
2272targets.
2273.It Ic .PRECIOUS
2274When
2275.Nm
2276is interrupted, it normally removes any partially made targets.
2277This source prevents the target from being removed.
2278.It Ic .RECURSIVE
2279Synonym for
2280.Ic .MAKE .
2281.It Ic .SILENT
2282Do not echo any of the commands associated with this target, exactly
2283as if they all were preceded by an at sign
2284.Pq Ql @ .
2285.It Ic .USE
2286Turn the target into
2287.Nm Ns 's
2288version of a macro.
2289When the target is used as a source for another target, the other target
2290acquires the commands, sources, and attributes (except for
2291.Ic .USE )
2292of the
2293source.
2294If the target already has commands, the
2295.Ic .USE
2296target's commands are appended
2297to them.
2298.It Ic .USEBEFORE
2299Like
2300.Ic .USE ,
2301but instead of appending, prepend the
2302.Ic .USEBEFORE
2303target commands to the target.
2304.It Ic .WAIT
2305If
2306.Ic .WAIT
2307appears in a dependency line, the sources that precede it are
2308made before the sources that succeed it in the line.
2309Since the dependents of files are not made until the file itself
2310could be made, this also stops the dependents being built unless they
2311are needed for another branch of the dependency tree.
2312So given:
2313.Bd -literal
2314x: a .WAIT b
2315	echo x
2316a:
2317	echo a
2318b: b1
2319	echo b
2320b1:
2321	echo b1
2322
2323.Ed
2324the output is always
2325.Ql a ,
2326.Ql b1 ,
2327.Ql b ,
2328.Ql x .
2329.Pp
2330The ordering imposed by
2331.Ic .WAIT
2332is only relevant for parallel makes.
2333.El
2334.Sh SPECIAL TARGETS
2335Special targets may not be included with other targets, i.e. they must be
2336the only target specified.
2337.Bl -tag -width .BEGINx
2338.It Ic .BEGIN
2339Any command lines attached to this target are executed before anything
2340else is done.
2341.It Ic .DEFAULT
2342This is sort of a
2343.Ic .USE
2344rule for any target (that was used only as a source) that
2345.Nm
2346can't figure out any other way to create.
2347Only the shell script is used.
2348The
2349.Va .IMPSRC
2350variable of a target that inherits
2351.Ic .DEFAULT Ns 's
2352commands is set to the target's own name.
2353.It Ic .DELETE_ON_ERROR
2354If this target is present in the makefile, it globally causes make to
2355delete targets whose commands fail.
2356(By default, only targets whose commands are interrupted during
2357execution are deleted.
2358This is the historical behavior.)
2359This setting can be used to help prevent half-finished or malformed
2360targets from being left around and corrupting future rebuilds.
2361.It Ic .END
2362Any command lines attached to this target are executed after everything
2363else is done successfully.
2364.It Ic .ERROR
2365Any command lines attached to this target are executed when another target fails.
2366The
2367.Va .ERROR_TARGET
2368variable is set to the target that failed.
2369See also
2370.Va MAKE_PRINT_VAR_ON_ERROR .
2371.It Ic .IGNORE
2372Mark each of the sources with the
2373.Ic .IGNORE
2374attribute.
2375If no sources are specified, this is the equivalent of specifying the
2376.Fl i
2377option.
2378.It Ic .INTERRUPT
2379If
2380.Nm
2381is interrupted, the commands for this target are executed.
2382.It Ic .MAIN
2383If no target is specified when
2384.Nm
2385is invoked, this target is built.
2386.It Ic .MAKEFLAGS
2387This target provides a way to specify flags for
2388.Nm
2389at the time when the makefiles are read.
2390The flags are as if typed to the shell, though the
2391.Fl f
2392option has
2393no effect.
2394.\" XXX: NOT YET!!!!
2395.\" .It Ic .NOTPARALLEL
2396.\" The named targets are executed in non parallel mode.
2397.\" If no targets are
2398.\" specified, all targets are executed in non parallel mode.
2399.It Ic .NOPATH
2400Apply the
2401.Ic .NOPATH
2402attribute to any specified sources.
2403.It Ic .NOTPARALLEL
2404Disable parallel mode.
2405.It Ic .NO_PARALLEL
2406Synonym for
2407.Ic .NOTPARALLEL ,
2408for compatibility with other pmake variants.
2409.It Ic .NOREADONLY
2410clear the read-only attribute from the global variables specified as sources.
2411.It Ic .OBJDIR
2412The source is a new value for
2413.Sq Va .OBJDIR .
2414If it exists,
2415.Nm
2416changes the current working directory to it and updates the value of
2417.Sq Va .OBJDIR .
2418.It Ic .ORDER
2419In parallel mode, the named targets are made in sequence.
2420This ordering does not add targets to the list of targets to be made.
2421.Pp
2422Since the dependents of a target do not get built until the target itself
2423could be built, unless
2424.Ql a
2425is built by another part of the dependency graph,
2426the following is a dependency loop:
2427.Bd -literal
2428\&.ORDER: b a
2429b: a
2430.Ed
2431.Pp
2432.\" XXX: NOT YET!!!!
2433.\" .It Ic .PARALLEL
2434.\" The named targets are executed in parallel mode.
2435.\" If no targets are
2436.\" specified, all targets are executed in parallel mode.
2437.It Ic .PATH
2438The sources are directories which are to be searched for files not
2439found in the current directory.
2440If no sources are specified,
2441any previously specified directories are removed from the search path.
2442If the source is the special
2443.Ic .DOTLAST
2444target, the current working directory is searched last.
2445.It Ic .PATH. Ns Ar suffix
2446Like
2447.Ic .PATH
2448but applies only to files with a particular suffix.
2449The suffix must have been previously declared with
2450.Ic .SUFFIXES .
2451.It Ic .PHONY
2452Apply the
2453.Ic .PHONY
2454attribute to any specified sources.
2455.It Ic .POSIX
2456If this is the first non-comment line in the main makefile,
2457the variable
2458.Va %POSIX
2459is set to the value
2460.Ql 1003.2
2461and the makefile
2462.Ql <posix.mk>
2463is included if it exists,
2464to provide POSIX-compatible default rules.
2465If
2466.Nm
2467is run with the
2468.Fl r
2469flag, only
2470.Ql posix.mk
2471contributes to the default rules.
2472.It Ic .PRECIOUS
2473Apply the
2474.Ic .PRECIOUS
2475attribute to any specified sources.
2476If no sources are specified, the
2477.Ic .PRECIOUS
2478attribute is applied to every target in the file.
2479.It Ic .READONLY
2480set the read-only attribute on the global variables specified as sources.
2481.It Ic .SHELL
2482Sets the shell that
2483.Nm
2484uses to execute commands in jobs mode.
2485The sources are a set of
2486.Ar field\| Ns Cm \&= Ns Ar value
2487pairs.
2488.Bl -tag -width ".Li hasErrCtls"
2489.It Li name
2490This is the minimal specification, used to select one of the built-in
2491shell specs;
2492.Li sh ,
2493.Li ksh ,
2494and
2495.Li csh .
2496.It Li path
2497Specifies the absolute path to the shell.
2498.It Li hasErrCtl
2499Indicates whether the shell supports exit on error.
2500.It Li check
2501The command to turn on error checking.
2502.It Li ignore
2503The command to disable error checking.
2504.It Li echo
2505The command to turn on echoing of commands executed.
2506.It Li quiet
2507The command to turn off echoing of commands executed.
2508.It Li filter
2509The output to filter after issuing the
2510.Li quiet
2511command.
2512It is typically identical to
2513.Li quiet .
2514.It Li errFlag
2515The flag to pass the shell to enable error checking.
2516.It Li echoFlag
2517The flag to pass the shell to enable command echoing.
2518.It Li newline
2519The string literal to pass the shell that results in a single newline
2520character when used outside of any quoting characters.
2521.El
2522Example:
2523.Bd -literal
2524\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2525	check="set \-e" ignore="set +e" \e
2526	echo="set \-v" quiet="set +v" filter="set +v" \e
2527	echoFlag=v errFlag=e newline="'\en'"
2528.Ed
2529.It Ic .SILENT
2530Apply the
2531.Ic .SILENT
2532attribute to any specified sources.
2533If no sources are specified, the
2534.Ic .SILENT
2535attribute is applied to every
2536command in the file.
2537.It Ic .STALE
2538This target gets run when a dependency file contains stale entries, having
2539.Va .ALLSRC
2540set to the name of that dependency file.
2541.It Ic .SUFFIXES
2542Each source specifies a suffix to
2543.Nm .
2544If no sources are specified, any previously specified suffixes are deleted.
2545It allows the creation of suffix-transformation rules.
2546.Pp
2547Example:
2548.Bd -literal
2549\&.SUFFIXES: .c .o
2550\&.c.o:
2551	cc \-o ${.TARGET} \-c ${.IMPSRC}
2552.Ed
2553.It Ic .SYSPATH
2554The sources are directories which are to be added to the system
2555include path which
2556.Nm
2557searches for makefiles.
2558If no sources are specified,
2559any previously specified directories are removed from the system
2560include path.
2561.El
2562.Sh ENVIRONMENT
2563.Nm
2564uses the following environment variables, if they exist:
2565.Ev MACHINE ,
2566.Ev MACHINE_ARCH ,
2567.Ev MAKE ,
2568.Ev MAKEFLAGS ,
2569.Ev MAKEOBJDIR ,
2570.Ev MAKEOBJDIRPREFIX ,
2571.Ev MAKESYSPATH ,
2572.Ev PWD ,
2573and
2574.Ev TMPDIR .
2575.Pp
2576.Ev MAKEOBJDIRPREFIX
2577and
2578.Ev MAKEOBJDIR
2579may only be set in the environment or on the command line to
2580.Nm
2581and not as makefile variables;
2582see the description of
2583.Sq Va .OBJDIR
2584for more details.
2585.Sh FILES
2586.Bl -tag -width /usr/share/mk -compact
2587.It .depend
2588list of dependencies
2589.It makefile
2590first default makefile if no makefile is specified on the command line
2591.It Makefile
2592second default makefile if no makefile is specified on the command line
2593.It sys.mk
2594system makefile
2595.It /usr/share/mk
2596system makefile directory
2597.El
2598.Sh COMPATIBILITY
2599The basic make syntax is compatible between different make variants;
2600however the special variables, variable modifiers and conditionals are not.
2601.Ss Older versions
2602An incomplete list of changes in older versions of
2603.Nm :
2604.Pp
2605The way that .for loop variables are substituted changed after
2606NetBSD 5.0
2607so that they still appear to be variable expansions.
2608In particular this stops them being treated as syntax, and removes some
2609obscure problems using them in .if statements.
2610.Pp
2611The way that parallel makes are scheduled changed in
2612NetBSD 4.0
2613so that .ORDER and .WAIT apply recursively to the dependent nodes.
2614The algorithms used may change again in the future.
2615.Ss Other make dialects
2616Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
2617support most of the features of
2618.Nm
2619as described in this manual.
2620Most notably:
2621.Bl -bullet -offset indent
2622.It
2623The
2624.Ic .WAIT
2625and
2626.Ic .ORDER
2627declarations and most functionality pertaining to parallelization.
2628(GNU make supports parallelization but lacks the features needed to
2629control it effectively.)
2630.It
2631Directives, including for loops and conditionals and most of the
2632forms of include files.
2633(GNU make has its own incompatible and less powerful syntax for
2634conditionals.)
2635.\" The "less powerful" above means that GNU make does not have the
2636.\" make(target), target(target) and commands(target) functions.
2637.It
2638All built-in variables that begin with a dot.
2639.It
2640Most of the special sources and targets that begin with a dot,
2641with the notable exception of
2642.Ic .PHONY ,
2643.Ic .PRECIOUS ,
2644and
2645.Ic .SUFFIXES .
2646.It
2647Variable modifiers, except for the
2648.Ql :old=new
2649string substitution, which does not portably support globbing with
2650.Ql %
2651and historically only works on declared suffixes.
2652.It
2653The
2654.Ic $>
2655variable even in its short form; most makes support this functionality
2656but its name varies.
2657.El
2658.Pp
2659Some features are somewhat more portable, such as assignment with
2660.Ic += ,
2661.Ic ?= ,
2662and
2663.Ic != .
2664The
2665.Va .PATH
2666functionality is based on an older feature
2667.Ic VPATH
2668found in GNU make and many versions of SVR4 make; however,
2669historically its behavior is too ill-defined (and too buggy) to rely
2670upon.
2671.Pp
2672The
2673.Ic $@
2674and
2675.Ic $<
2676variables are more or less universally portable, as is the
2677.Ic $(MAKE)
2678variable.
2679Basic use of suffix rules (for files only in the current directory,
2680not trying to chain transformations together, etc.) is also reasonably
2681portable.
2682.Sh SEE ALSO
2683.Xr mkdep 1
2684.Sh HISTORY
2685.Nm
2686is derived from NetBSD
2687.Xr make 1 .
2688It uses autoconf to facilitate portability to other platforms.
2689.Pp
2690A
2691make
2692command appeared in
2693.At v7 .
2694This
2695make
2696implementation is based on Adam de Boor's pmake program,
2697which was written for Sprite at Berkeley.
2698It was designed to be a parallel distributed make running jobs on different
2699machines using a daemon called
2700.Dq customs .
2701.Pp
2702Historically the target/dependency
2703.Ic FRC
2704has been used to FoRCe rebuilding (since the target/dependency
2705does not exist ... unless someone creates an
2706.Pa FRC
2707file).
2708.Sh BUGS
2709The
2710make
2711syntax is difficult to parse.
2712For instance, finding the end of a variable's use should involve scanning
2713each of the modifiers, using the correct terminator for each field.
2714In many places
2715make
2716just counts {} and () in order to find the end of a variable expansion.
2717.Pp
2718There is no way of escaping a space character in a filename.
2719