xref: /freebsd/contrib/bmake/bmake.1 (revision a2aef24aa3c8458e4036735dd6928b4ef77294e5)
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3.\" Copyright (c) 1990, 1993
4.\"	The Regents of the University of California.  All rights reserved.
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7.\" modification, are permitted provided that the following conditions
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10.\"    notice, this list of conditions and the following disclaimer.
11.\" 2. Redistributions in binary form must reproduce the above copyright
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13.\"    documentation and/or other materials provided with the distribution.
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15.\"    may be used to endorse or promote products derived from this software
16.\"    without specific prior written permission.
17.\"
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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
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29.\"
30.\"	from: @(#)make.1	8.4 (Berkeley) 3/19/94
31.\"
32.Dd June 22, 2017
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 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 Fl v Ar variable
52.Op Ar variable=value
53.Op Ar target ...
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
61makefile option is given,
62.Nm
63will try to open
64.Ql Pa makefile
65then
66.Ql Pa Makefile
67in order to find the specifications.
68If the file
69.Ql 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.Pp
79.Nm
80will prepend the contents of the
81.Va MAKEFLAGS
82environment variable to the command line arguments before parsing them.
83.Pp
84The options are as follows:
85.Bl -tag -width Ds
86.It Fl B
87Try to be backwards compatible by executing a single shell per command and
88by executing the commands to make the sources of a dependency line in sequence.
89.It Fl C Ar directory
90Change to
91.Ar directory
92before reading the makefiles or doing anything else.
93If multiple
94.Fl C
95options are specified, each is interpreted relative to the previous one:
96.Fl C Pa / Fl C Pa etc
97is equivalent to
98.Fl C Pa /etc .
99.It Fl D Ar variable
100Define
101.Ar variable
102to be 1, in the global context.
103.It Fl d Ar [-]flags
104Turn on debugging, and specify which portions of
105.Nm
106are to print debugging information.
107Unless the flags are preceded by
108.Ql \-
109they are added to the
110.Va MAKEFLAGS
111environment variable and will be processed by any child make processes.
112By default, debugging information is printed to standard error,
113but this can be changed using the
114.Ar F
115debugging flag.
116The debugging output is always unbuffered; in addition, if debugging
117is enabled but debugging output is not directed to standard output,
118then the standard output is line buffered.
119.Ar Flags
120is one or more of the following:
121.Bl -tag -width Ds
122.It Ar A
123Print all possible debugging information;
124equivalent to specifying all of the debugging flags.
125.It Ar a
126Print debugging information about archive searching and caching.
127.It Ar C
128Print debugging information about current working directory.
129.It Ar c
130Print debugging information about conditional evaluation.
131.It Ar d
132Print debugging information about directory searching and caching.
133.It Ar e
134Print debugging information about failed commands and targets.
135.It Ar F Ns Oo Sy \&+ Oc Ns Ar filename
136Specify where debugging output is written.
137This must be the last flag, because it consumes the remainder of
138the argument.
139If the character immediately after the
140.Ql F
141flag is
142.Ql \&+ ,
143then the file will be opened in append mode;
144otherwise the file will be overwritten.
145If the file name is
146.Ql stdout
147or
148.Ql stderr
149then debugging output will be written to the
150standard output or standard error output file descriptors respectively
151(and the
152.Ql \&+
153option has no effect).
154Otherwise, the output will be written to the named file.
155If the file name ends
156.Ql .%d
157then the
158.Ql %d
159is replaced by the pid.
160.It Ar f
161Print debugging information about loop evaluation.
162.It Ar "g1"
163Print the input graph before making anything.
164.It Ar "g2"
165Print the input graph after making everything, or before exiting
166on error.
167.It Ar "g3"
168Print the input graph before exiting on error.
169.It Ar j
170Print debugging information about running multiple shells.
171.It Ar l
172Print commands in Makefiles regardless of whether or not they are prefixed by
173.Ql @
174or other "quiet" flags.
175Also known as "loud" behavior.
176.It Ar M
177Print debugging information about "meta" mode decisions about targets.
178.It Ar m
179Print debugging information about making targets, including modification
180dates.
181.It Ar n
182Don't delete the temporary command scripts created when running commands.
183These temporary scripts are created in the directory
184referred to by the
185.Ev TMPDIR
186environment variable, or in
187.Pa /tmp
188if
189.Ev TMPDIR
190is unset or set to the empty string.
191The temporary scripts are created by
192.Xr mkstemp 3 ,
193and have names of the form
194.Pa makeXXXXXX .
195.Em NOTE :
196This can create many files in
197.Ev TMPDIR
198or
199.Pa /tmp ,
200so use with care.
201.It Ar p
202Print debugging information about makefile parsing.
203.It Ar s
204Print debugging information about suffix-transformation rules.
205.It Ar t
206Print debugging information about target list maintenance.
207.It Ar V
208Force the
209.Fl V
210option to print raw values of variables, overriding the default behavior
211set via
212.Va .MAKE.EXPAND_VARIABLES .
213.It Ar v
214Print debugging information about variable assignment.
215.It Ar x
216Run shell commands with
217.Fl x
218so the actual commands are printed as they are executed.
219.El
220.It Fl e
221Specify that environment variables override macro assignments within
222makefiles.
223.It Fl f Ar makefile
224Specify a makefile to read instead of the default
225.Ql Pa makefile .
226If
227.Ar makefile
228is
229.Ql Fl ,
230standard input is read.
231Multiple makefiles may be specified, and are read in the order specified.
232.It Fl I Ar directory
233Specify a directory in which to search for makefiles and included makefiles.
234The system makefile directory (or directories, see the
235.Fl m
236option) is automatically included as part of this list.
237.It Fl i
238Ignore non-zero exit of shell commands in the makefile.
239Equivalent to specifying
240.Ql Fl
241before each command line in the makefile.
242.It Fl J Ar private
243This option should
244.Em not
245be specified by the user.
246.Pp
247When the
248.Ar j
249option is in use in a recursive build, this option is passed by a make
250to child makes to allow all the make processes in the build to
251cooperate to avoid overloading the system.
252.It Fl j Ar max_jobs
253Specify the maximum number of jobs that
254.Nm
255may have running at any one time.
256The value is saved in
257.Va .MAKE.JOBS .
258Turns compatibility mode off, unless the
259.Ar B
260flag is also specified.
261When compatibility mode is off, all commands associated with a
262target are executed in a single shell invocation as opposed to the
263traditional one shell invocation per line.
264This can break traditional scripts which change directories on each
265command invocation and then expect to start with a fresh environment
266on the next line.
267It is more efficient to correct the scripts rather than turn backwards
268compatibility on.
269.It Fl k
270Continue processing after errors are encountered, but only on those targets
271that do not depend on the target whose creation caused the error.
272.It Fl m Ar directory
273Specify a directory in which to search for sys.mk and makefiles included
274via the
275.Ao Ar file Ac Ns -style
276include statement.
277The
278.Fl m
279option can be used multiple times to form a search path.
280This path will override the default system include path: /usr/share/mk.
281Furthermore the system include path will be appended to the search path used
282for
283.Qo Ar file Qc Ns -style
284include statements (see the
285.Fl I
286option).
287.Pp
288If a file or directory name in the
289.Fl m
290argument (or the
291.Ev MAKESYSPATH
292environment variable) starts with the string
293.Qq \&.../
294then
295.Nm
296will search for the specified file or directory named in the remaining part
297of the argument string.
298The search starts with the current directory of
299the Makefile and then works upward towards the root of the file system.
300If the search is successful, then the resulting directory replaces the
301.Qq \&.../
302specification in the
303.Fl m
304argument.
305If used, this feature allows
306.Nm
307to easily search in the current source tree for customized sys.mk files
308(e.g., by using
309.Qq \&.../mk/sys.mk
310as an argument).
311.It Fl n
312Display the commands that would have been executed, but do not
313actually execute them unless the target depends on the .MAKE special
314source (see below).
315.It Fl N
316Display the commands which would have been executed, but do not
317actually execute any of them; useful for debugging top-level makefiles
318without descending into subdirectories.
319.It Fl q
320Do not execute any commands, but exit 0 if the specified targets are
321up-to-date and 1, otherwise.
322.It Fl r
323Do not use the built-in rules specified in the system makefile.
324.It Fl s
325Do not echo any commands as they are executed.
326Equivalent to specifying
327.Ql Ic @
328before each command line in the makefile.
329.It Fl T Ar tracefile
330When used with the
331.Fl j
332flag,
333append a trace record to
334.Ar tracefile
335for each job started and completed.
336.It Fl t
337Rather than re-building a target as specified in the makefile, create it
338or update its modification time to make it appear up-to-date.
339.It Fl V Ar variable
340Print the value of
341.Ar variable .
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.
346The value printed is extracted from the global context after all
347makefiles have been read.
348By default, the raw variable contents (which may
349include additional unexpanded variable references) are shown.
350If
351.Ar variable
352contains a
353.Ql \&$
354then the value will be recursively expanded to its complete resultant
355text before printing.
356The expanded value will also be printed if
357.Va .MAKE.EXPAND_VARIABLES
358is set to true and
359the
360.Fl dV
361option has not been used to override it.
362Note that loop-local and target-local variables, as well as values
363taken temporarily by global variables during makefile processing, are
364not accessible via this option.
365The
366.Fl dv
367debug mode can be used to see these at the cost of generating
368substantial extraneous output.
369.It Fl v Ar variable
370Like
371.Fl V
372but the variable is always expanded to its complete value.
373.It Fl W
374Treat any warnings during makefile parsing as errors.
375.It Fl w
376Print entering and leaving directory messages, pre and post processing.
377.It Fl X
378Don't export variables passed on the command line to the environment
379individually.
380Variables passed on the command line are still exported
381via the
382.Va MAKEFLAGS
383environment variable.
384This option may be useful on systems which have a small limit on the
385size of command arguments.
386.It Ar variable=value
387Set the value of the variable
388.Ar variable
389to
390.Ar value .
391Normally, all values passed on the command line are also exported to
392sub-makes in the environment.
393The
394.Fl X
395flag disables this behavior.
396Variable assignments should follow options for POSIX compatibility
397but no ordering is enforced.
398.El
399.Pp
400There are seven different types of lines in a makefile: file dependency
401specifications, shell commands, variable assignments, include statements,
402conditional directives, for loops, and comments.
403.Pp
404In general, lines may be continued from one line to the next by ending
405them with a backslash
406.Pq Ql \e .
407The trailing newline character and initial whitespace on the following
408line are compressed into a single space.
409.Sh FILE DEPENDENCY SPECIFICATIONS
410Dependency lines consist of one or more targets, an operator, and zero
411or more sources.
412This creates a relationship where the targets
413.Dq depend
414on the sources
415and are usually created from them.
416The exact relationship between the target and the source is determined
417by the operator that separates them.
418The three operators are as follows:
419.Bl -tag -width flag
420.It Ic \&:
421A target is considered out-of-date if its modification time is less than
422those of any of its sources.
423Sources for a target accumulate over dependency lines when this operator
424is used.
425The target is removed if
426.Nm
427is interrupted.
428.It Ic \&!
429Targets are always re-created, but not until all sources have been
430examined and re-created as necessary.
431Sources for a target accumulate over dependency lines when this operator
432is used.
433The target is removed if
434.Nm
435is interrupted.
436.It Ic \&::
437If no sources are specified, the target is always re-created.
438Otherwise, a target is considered out-of-date if any of its sources has
439been modified more recently than the target.
440Sources for a target do not accumulate over dependency lines when this
441operator is used.
442The target will not be removed if
443.Nm
444is interrupted.
445.El
446.Pp
447Targets and sources may contain the shell wildcard values
448.Ql \&? ,
449.Ql * ,
450.Ql [] ,
451and
452.Ql {} .
453The values
454.Ql \&? ,
455.Ql * ,
456and
457.Ql []
458may only be used as part of the final
459component of the target or source, and must be used to describe existing
460files.
461The value
462.Ql {}
463need not necessarily be used to describe existing files.
464Expansion is in directory order, not alphabetically as done in the shell.
465.Sh SHELL COMMANDS
466Each target may have associated with it one or more lines of shell
467commands, normally
468used to create the target.
469Each of the lines in this script
470.Em must
471be preceded by a tab.
472(For historical reasons, spaces are not accepted.)
473While targets can appear in many dependency lines if desired, by
474default only one of these rules may be followed by a creation
475script.
476If the
477.Ql Ic \&::
478operator is used, however, all rules may include scripts and the
479scripts are executed in the order found.
480.Pp
481Each line is treated as a separate shell command, unless the end of
482line is escaped with a backslash
483.Pq Ql \e
484in which case that line and the next are combined.
485.\" The escaped newline is retained and passed to the shell, which
486.\" normally ignores it.
487.\" However, the tab at the beginning of the following line is removed.
488If the first characters of the command are any combination of
489.Ql Ic @ ,
490.Ql Ic + ,
491or
492.Ql Ic \- ,
493the command is treated specially.
494A
495.Ql Ic @
496causes the command not to be echoed before it is executed.
497A
498.Ql Ic +
499causes the command to be executed even when
500.Fl n
501is given.
502This is similar to the effect of the .MAKE special source,
503except that the effect can be limited to a single line of a script.
504A
505.Ql Ic \-
506in compatibility mode
507causes any non-zero exit status of the command line to be ignored.
508.Pp
509When
510.Nm
511is run in jobs mode with
512.Fl j Ar max_jobs ,
513the entire script for the target is fed to a
514single instance of the shell.
515In compatibility (non-jobs) mode, each command is run in a separate process.
516If the command contains any shell meta characters
517.Pq Ql #=|^(){};&<>*?[]:$`\e\en
518it will be passed to the shell; otherwise
519.Nm
520will attempt direct execution.
521If a line starts with
522.Ql Ic \-
523and the shell has ErrCtl enabled then failure of the command line
524will be ignored as in compatibility mode.
525Otherwise
526.Ql Ic \-
527affects the entire job;
528the script will stop at the first command line that fails,
529but the target will not be deemed to have failed.
530.Pp
531Makefiles should be written so that the mode of
532.Nm
533operation does not change their behavior.
534For example, any command which needs to use
535.Dq cd
536or
537.Dq chdir
538without potentially changing the directory for subsequent commands
539should be put in parentheses so it executes in a subshell.
540To force the use of one shell, escape the line breaks so as to make
541the whole script one command.
542For example:
543.Bd -literal -offset indent
544avoid-chdir-side-effects:
545	@echo Building $@ in `pwd`
546	@(cd ${.CURDIR} && ${MAKE} $@)
547	@echo Back in `pwd`
548
549ensure-one-shell-regardless-of-mode:
550	@echo Building $@ in `pwd`; \e
551	(cd ${.CURDIR} && ${MAKE} $@); \e
552	echo Back in `pwd`
553.Ed
554.Pp
555Since
556.Nm
557will
558.Xr chdir 2
559to
560.Ql Va .OBJDIR
561before executing any targets, each child process
562starts with that as its current working directory.
563.Sh VARIABLE ASSIGNMENTS
564Variables in make are much like variables in the shell, and, by tradition,
565consist of all upper-case letters.
566.Ss Variable assignment modifiers
567The five operators that can be used to assign values to variables are as
568follows:
569.Bl -tag -width Ds
570.It Ic \&=
571Assign the value to the variable.
572Any previous value is overridden.
573.It Ic \&+=
574Append the value to the current value of the variable.
575.It Ic \&?=
576Assign the value to the variable if it is not already defined.
577.It Ic \&:=
578Assign with expansion, i.e. expand the value before assigning it
579to the variable.
580Normally, expansion is not done until the variable is referenced.
581.Em NOTE :
582References to undefined variables are
583.Em not
584expanded.
585This can cause problems when variable modifiers are used.
586.It Ic \&!=
587Expand the value and pass it to the shell for execution and assign
588the result to the variable.
589Any newlines in the result are replaced with spaces.
590.El
591.Pp
592Any white-space before the assigned
593.Ar value
594is removed; if the value is being appended, a single space is inserted
595between the previous contents of the variable and the appended value.
596.Pp
597Variables are expanded by surrounding the variable name with either
598curly braces
599.Pq Ql {}
600or parentheses
601.Pq Ql ()
602and preceding it with
603a dollar sign
604.Pq Ql \&$ .
605If the variable name contains only a single letter, the surrounding
606braces or parentheses are not required.
607This shorter form is not recommended.
608.Pp
609If the variable name contains a dollar, then the name itself is expanded first.
610This allows almost arbitrary variable names, however names containing dollar,
611braces, parenthesis, or whitespace are really best avoided!
612.Pp
613If the result of expanding a variable contains a dollar sign
614.Pq Ql \&$
615the string is expanded again.
616.Pp
617Variable substitution occurs at three distinct times, depending on where
618the variable is being used.
619.Bl -enum
620.It
621Variables in dependency lines are expanded as the line is read.
622.It
623Variables in shell commands are expanded when the shell command is
624executed.
625.It
626.Dq .for
627loop index variables are expanded on each loop iteration.
628Note that other variables are not expanded inside loops so
629the following example code:
630.Bd -literal -offset indent
631
632.Dv .for i in 1 2 3
633a+=     ${i}
634j=      ${i}
635b+=     ${j}
636.Dv .endfor
637
638all:
639	@echo ${a}
640	@echo ${b}
641
642.Ed
643will print:
644.Bd -literal -offset indent
6451 2 3
6463 3 3
647
648.Ed
649Because while ${a} contains
650.Dq 1 2 3
651after the loop is executed, ${b}
652contains
653.Dq ${j} ${j} ${j}
654which expands to
655.Dq 3 3 3
656since after the loop completes ${j} contains
657.Dq 3 .
658.El
659.Ss Variable classes
660The four different classes of variables (in order of increasing precedence)
661are:
662.Bl -tag -width Ds
663.It Environment variables
664Variables defined as part of
665.Nm Ns 's
666environment.
667.It Global variables
668Variables defined in the makefile or in included makefiles.
669.It Command line variables
670Variables defined as part of the command line.
671.It Local variables
672Variables that are defined specific to a certain target.
673.El
674.Pp
675Local variables are all built in and their values vary magically from
676target to target.
677It is not currently possible to define new local variables.
678The seven local variables are as follows:
679.Bl -tag -width ".ARCHIVE" -offset indent
680.It Va .ALLSRC
681The list of all sources for this target; also known as
682.Ql Va \&> .
683.It Va .ARCHIVE
684The name of the archive file; also known as
685.Ql Va \&! .
686.It Va .IMPSRC
687In suffix-transformation rules, the name/path of the source from which the
688target is to be transformed (the
689.Dq implied
690source); also known as
691.Ql Va \&< .
692It is not defined in explicit rules.
693.It Va .MEMBER
694The name of the archive member; also known as
695.Ql Va % .
696.It Va .OODATE
697The list of sources for this target that were deemed out-of-date; also
698known as
699.Ql Va \&? .
700.It Va .PREFIX
701The file prefix of the target, containing only the file portion, no suffix
702or preceding directory components; also known as
703.Ql Va * .
704The suffix must be one of the known suffixes declared with
705.Ic .SUFFIXES
706or it will not be recognized.
707.It Va .TARGET
708The name of the target; also known as
709.Ql Va @ .
710For compatibility with other makes this is an alias for
711.Ic .ARCHIVE
712in archive member rules.
713.El
714.Pp
715The shorter forms
716.Ql ( Va > ,
717.Ql Va \&! ,
718.Ql Va < ,
719.Ql Va % ,
720.Ql Va \&? ,
721.Ql Va * ,
722and
723.Ql Va @ )
724are permitted for backward
725compatibility with historical makefiles and legacy POSIX make and are
726not recommended.
727.Pp
728Variants of these variables with the punctuation followed immediately by
729.Ql D
730or
731.Ql F ,
732e.g.
733.Ql Va $(@D) ,
734are legacy forms equivalent to using the
735.Ql :H
736and
737.Ql :T
738modifiers.
739These forms are accepted for compatibility with
740.At V
741makefiles and POSIX but are not recommended.
742.Pp
743Four of the local variables may be used in sources on dependency lines
744because they expand to the proper value for each target on the line.
745These variables are
746.Ql Va .TARGET ,
747.Ql Va .PREFIX ,
748.Ql Va .ARCHIVE ,
749and
750.Ql Va .MEMBER .
751.Ss Additional built-in variables
752In addition,
753.Nm
754sets or knows about the following variables:
755.Bl -tag -width .MAKEOVERRIDES
756.It Va \&$
757A single dollar sign
758.Ql \&$ ,
759i.e.
760.Ql \&$$
761expands to a single dollar
762sign.
763.It Va .ALLTARGETS
764The list of all targets encountered in the Makefile.
765If evaluated during
766Makefile parsing, lists only those targets encountered thus far.
767.It Va .CURDIR
768A path to the directory where
769.Nm
770was executed.
771Refer to the description of
772.Ql Ev PWD
773for more details.
774.It Va .INCLUDEDFROMDIR
775The directory of the file this Makefile was included from.
776.It Va .INCLUDEDFROMFILE
777The filename of the file this Makefile was included from.
778.It Ev MAKE
779The name that
780.Nm
781was executed with
782.Pq Va argv[0] .
783For compatibility
784.Nm
785also sets
786.Va .MAKE
787with the same value.
788The preferred variable to use is the environment variable
789.Ev MAKE
790because it is more compatible with other versions of
791.Nm
792and cannot be confused with the special target with the same name.
793.It Va .MAKE.DEPENDFILE
794Names the makefile (default
795.Ql Pa .depend )
796from which generated dependencies are read.
797.It Va .MAKE.EXPAND_VARIABLES
798A boolean that controls the default behavior of the
799.Fl V
800option.
801If true, variable values printed with
802.Fl V
803are fully expanded; if false, the raw variable contents (which may
804include additional unexpanded variable references) are shown.
805.It Va .MAKE.EXPORTED
806The list of variables exported by
807.Nm .
808.It Va .MAKE.JOBS
809The argument to the
810.Fl j
811option.
812.It Va .MAKE.JOB.PREFIX
813If
814.Nm
815is run with
816.Ar j
817then output for each target is prefixed with a token
818.Ql --- target ---
819the first part of which can be controlled via
820.Va .MAKE.JOB.PREFIX .
821If
822.Va .MAKE.JOB.PREFIX
823is empty, no token is printed.
824.br
825For example:
826.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
827would produce tokens like
828.Ql ---make[1234] target ---
829making it easier to track the degree of parallelism being achieved.
830.It Ev MAKEFLAGS
831The environment variable
832.Ql Ev MAKEFLAGS
833may contain anything that
834may be specified on
835.Nm Ns 's
836command line.
837Anything specified on
838.Nm Ns 's
839command line is appended to the
840.Ql Ev MAKEFLAGS
841variable which is then
842entered into the environment for all programs which
843.Nm
844executes.
845.It Va .MAKE.LEVEL
846The recursion depth of
847.Nm .
848The initial instance of
849.Nm
850will be 0, and an incremented value is put into the environment
851to be seen by the next generation.
852This allows tests like:
853.Li .if ${.MAKE.LEVEL} == 0
854to protect things which should only be evaluated in the initial instance of
855.Nm .
856.It Va .MAKE.MAKEFILE_PREFERENCE
857The ordered list of makefile names
858(default
859.Ql Pa makefile ,
860.Ql Pa Makefile )
861that
862.Nm
863will look for.
864.It Va .MAKE.MAKEFILES
865The list of makefiles read by
866.Nm ,
867which is useful for tracking dependencies.
868Each makefile is recorded only once, regardless of the number of times read.
869.It Va .MAKE.MODE
870Processed after reading all makefiles.
871Can affect the mode that
872.Nm
873runs in.
874It can contain a number of keywords:
875.Bl -hang -width missing-filemon=bf.
876.It Pa compat
877Like
878.Fl B ,
879puts
880.Nm
881into "compat" mode.
882.It Pa meta
883Puts
884.Nm
885into "meta" mode, where meta files are created for each target
886to capture the command run, the output generated and if
887.Xr filemon 4
888is available, the system calls which are of interest to
889.Nm .
890The captured output can be very useful when diagnosing errors.
891.It Pa curdirOk= Ar bf
892Normally
893.Nm
894will not create .meta files in
895.Ql Va .CURDIR .
896This can be overridden by setting
897.Va bf
898to a value which represents True.
899.It Pa missing-meta= Ar bf
900If
901.Va bf
902is True, then a missing .meta file makes the target out-of-date.
903.It Pa missing-filemon= Ar bf
904If
905.Va bf
906is True, then missing filemon data makes the target out-of-date.
907.It Pa nofilemon
908Do not use
909.Xr filemon 4 .
910.It Pa env
911For debugging, it can be useful to include the environment
912in the .meta file.
913.It Pa verbose
914If in "meta" mode, print a clue about the target being built.
915This is useful if the build is otherwise running silently.
916The message printed the value of:
917.Va .MAKE.META.PREFIX .
918.It Pa ignore-cmd
919Some makefiles have commands which are simply not stable.
920This keyword causes them to be ignored for
921determining whether a target is out of date in "meta" mode.
922See also
923.Ic .NOMETA_CMP .
924.It Pa silent= Ar bf
925If
926.Va bf
927is True, when a .meta file is created, mark the target
928.Ic .SILENT .
929.El
930.It Va .MAKE.META.BAILIWICK
931In "meta" mode, provides a list of prefixes which
932match the directories controlled by
933.Nm .
934If a file that was generated outside of
935.Va .OBJDIR
936but within said bailiwick is missing,
937the current target is considered out-of-date.
938.It Va .MAKE.META.CREATED
939In "meta" mode, this variable contains a list of all the meta files
940updated.
941If not empty, it can be used to trigger processing of
942.Va .MAKE.META.FILES .
943.It Va .MAKE.META.FILES
944In "meta" mode, this variable contains a list of all the meta files
945used (updated or not).
946This list can be used to process the meta files to extract dependency
947information.
948.It Va .MAKE.META.IGNORE_PATHS
949Provides a list of path prefixes that should be ignored;
950because the contents are expected to change over time.
951The default list includes:
952.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
953.It Va .MAKE.META.IGNORE_PATTERNS
954Provides a list of patterns to match against pathnames.
955Ignore any that match.
956.It Va .MAKE.META.IGNORE_FILTER
957Provides a list of variable modifiers to apply to each pathname.
958Ignore if the expansion is an empty string.
959.It Va .MAKE.META.PREFIX
960Defines the message printed for each meta file updated in "meta verbose" mode.
961The default value is:
962.Dl Building ${.TARGET:H:tA}/${.TARGET:T}
963.It Va .MAKEOVERRIDES
964This variable is used to record the names of variables assigned to
965on the command line, so that they may be exported as part of
966.Ql Ev MAKEFLAGS .
967This behavior can be disabled by assigning an empty value to
968.Ql Va .MAKEOVERRIDES
969within a makefile.
970Extra variables can be exported from a makefile
971by appending their names to
972.Ql Va .MAKEOVERRIDES .
973.Ql Ev MAKEFLAGS
974is re-exported whenever
975.Ql Va .MAKEOVERRIDES
976is modified.
977.It Va .MAKE.PATH_FILEMON
978If
979.Nm
980was built with
981.Xr filemon 4
982support, this is set to the path of the device node.
983This allows makefiles to test for this support.
984.It Va .MAKE.PID
985The process-id of
986.Nm .
987.It Va .MAKE.PPID
988The parent process-id of
989.Nm .
990.It Va .MAKE.SAVE_DOLLARS
991value should be a boolean that controls whether
992.Ql $$
993are preserved when doing
994.Ql :=
995assignments.
996The default is false, for backwards compatibility.
997Set to true for compatability with other makes.
998If set to false,
999.Ql $$
1000becomes
1001.Ql $
1002per normal evaluation rules.
1003.It Va MAKE_PRINT_VAR_ON_ERROR
1004When
1005.Nm
1006stops due to an error, it sets
1007.Ql Va .ERROR_TARGET
1008to the name of the target that failed,
1009.Ql Va .ERROR_CMD
1010to the commands of the failed target,
1011and in "meta" mode, it also sets
1012.Ql Va .ERROR_CWD
1013to the
1014.Xr getcwd 3 ,
1015and
1016.Ql Va .ERROR_META_FILE
1017to the path of the meta file (if any) describing the failed target.
1018It then prints its name and the value of
1019.Ql Va .CURDIR
1020as well as the value of any variables named in
1021.Ql Va MAKE_PRINT_VAR_ON_ERROR .
1022.It Va .newline
1023This variable is simply assigned a newline character as its value.
1024This allows expansions using the
1025.Cm \&:@
1026modifier to put a newline between
1027iterations of the loop rather than a space.
1028For example, the printing of
1029.Ql Va MAKE_PRINT_VAR_ON_ERROR
1030could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
1031.It Va .OBJDIR
1032A path to the directory where the targets are built.
1033Its value is determined by trying to
1034.Xr chdir 2
1035to the following directories in order and using the first match:
1036.Bl -enum
1037.It
1038.Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
1039.Pp
1040(Only if
1041.Ql Ev MAKEOBJDIRPREFIX
1042is set in the environment or on the command line.)
1043.It
1044.Ev ${MAKEOBJDIR}
1045.Pp
1046(Only if
1047.Ql Ev MAKEOBJDIR
1048is set in the environment or on the command line.)
1049.It
1050.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
1051.It
1052.Ev ${.CURDIR} Ns Pa /obj
1053.It
1054.Pa /usr/obj/ Ns Ev ${.CURDIR}
1055.It
1056.Ev ${.CURDIR}
1057.El
1058.Pp
1059Variable expansion is performed on the value before it's used,
1060so expressions such as
1061.Dl ${.CURDIR:S,^/usr/src,/var/obj,}
1062may be used.
1063This is especially useful with
1064.Ql Ev MAKEOBJDIR .
1065.Pp
1066.Ql Va .OBJDIR
1067may be modified in the makefile via the special target
1068.Ql Ic .OBJDIR .
1069In all cases,
1070.Nm
1071will
1072.Xr chdir 2
1073to the specified directory if it exists, and set
1074.Ql Va .OBJDIR
1075and
1076.Ql Ev PWD
1077to that directory before executing any targets.
1078.
1079.It Va .PARSEDIR
1080A path to the directory of the current
1081.Ql Pa Makefile
1082being parsed.
1083.It Va .PARSEFILE
1084The basename of the current
1085.Ql Pa Makefile
1086being parsed.
1087This variable and
1088.Ql Va .PARSEDIR
1089are both set only while the
1090.Ql Pa Makefiles
1091are being parsed.
1092If you want to retain their current values, assign them to a variable
1093using assignment with expansion:
1094.Pq Ql Cm \&:= .
1095.It Va .PATH
1096A variable that represents the list of directories that
1097.Nm
1098will search for files.
1099The search list should be updated using the target
1100.Ql Va .PATH
1101rather than the variable.
1102.It Ev PWD
1103Alternate path to the current directory.
1104.Nm
1105normally sets
1106.Ql Va .CURDIR
1107to the canonical path given by
1108.Xr getcwd 3 .
1109However, if the environment variable
1110.Ql Ev PWD
1111is set and gives a path to the current directory, then
1112.Nm
1113sets
1114.Ql Va .CURDIR
1115to the value of
1116.Ql Ev PWD
1117instead.
1118This behavior is disabled if
1119.Ql Ev MAKEOBJDIRPREFIX
1120is set or
1121.Ql Ev MAKEOBJDIR
1122contains a variable transform.
1123.Ql Ev PWD
1124is set to the value of
1125.Ql Va .OBJDIR
1126for all programs which
1127.Nm
1128executes.
1129.It Ev .TARGETS
1130The list of targets explicitly specified on the command line, if any.
1131.It Ev VPATH
1132Colon-separated
1133.Pq Dq \&:
1134lists of directories that
1135.Nm
1136will search for files.
1137The variable is supported for compatibility with old make programs only,
1138use
1139.Ql Va .PATH
1140instead.
1141.El
1142.Ss Variable modifiers
1143Variable expansion may be modified to select or modify each word of the
1144variable (where a
1145.Dq word
1146is white-space delimited sequence of characters).
1147The general format of a variable expansion is as follows:
1148.Pp
1149.Dl ${variable[:modifier[:...]]}
1150.Pp
1151Each modifier begins with a colon,
1152which may be escaped with a backslash
1153.Pq Ql \e .
1154.Pp
1155A set of modifiers can be specified via a variable, as follows:
1156.Pp
1157.Dl modifier_variable=modifier[:...]
1158.Dl ${variable:${modifier_variable}[:...]}
1159.Pp
1160In this case the first modifier in the modifier_variable does not
1161start with a colon, since that must appear in the referencing
1162variable.
1163If any of the modifiers in the modifier_variable contain a dollar sign
1164.Pq Ql $ ,
1165these must be doubled to avoid early expansion.
1166.Pp
1167The supported modifiers are:
1168.Bl -tag -width EEE
1169.It Cm \&:E
1170Replaces each word in the variable with its suffix.
1171.It Cm \&:H
1172Replaces each word in the variable with everything but the last component.
1173.It Cm \&:M Ns Ar pattern
1174Select only those words that match
1175.Ar pattern .
1176The standard shell wildcard characters
1177.Pf ( Ql * ,
1178.Ql \&? ,
1179and
1180.Ql Oo Oc )
1181may
1182be used.
1183The wildcard characters may be escaped with a backslash
1184.Pq Ql \e .
1185As a consequence of the way values are split into words, matched,
1186and then joined, a construct like
1187.Dl ${VAR:M*}
1188will normalize the inter-word spacing, removing all leading and
1189trailing space, and converting multiple consecutive spaces
1190to single spaces.
1191.
1192.It Cm \&:N Ns Ar pattern
1193This is identical to
1194.Ql Cm \&:M ,
1195but selects all words which do not match
1196.Ar pattern .
1197.It Cm \&:O
1198Order every word in variable alphabetically.
1199To sort words in
1200reverse order use the
1201.Ql Cm \&:O:[-1..1]
1202combination of modifiers.
1203.It Cm \&:Ox
1204Randomize words in variable.
1205The results will be different each time you are referring to the
1206modified variable; use the assignment with expansion
1207.Pq Ql Cm \&:=
1208to prevent such behavior.
1209For example,
1210.Bd -literal -offset indent
1211LIST=			uno due tre quattro
1212RANDOM_LIST=		${LIST:Ox}
1213STATIC_RANDOM_LIST:=	${LIST:Ox}
1214
1215all:
1216	@echo "${RANDOM_LIST}"
1217	@echo "${RANDOM_LIST}"
1218	@echo "${STATIC_RANDOM_LIST}"
1219	@echo "${STATIC_RANDOM_LIST}"
1220.Ed
1221may produce output similar to:
1222.Bd -literal -offset indent
1223quattro due tre uno
1224tre due quattro uno
1225due uno quattro tre
1226due uno quattro tre
1227.Ed
1228.It Cm \&:Q
1229Quotes every shell meta-character in the variable, so that it can be passed
1230safely through recursive invocations of
1231.Nm .
1232.It Cm \&:R
1233Replaces each word in the variable with everything but its suffix.
1234.It Cm \&:range[=count]
1235The value is an integer sequence representing the words of the original
1236value, or the supplied
1237.Va count .
1238.It Cm \&:gmtime[=utc]
1239The value is a format string for
1240.Xr strftime 3 ,
1241using
1242.Xr gmtime 3 .
1243If a
1244.Va utc
1245value is not provided or is 0, the current time is used.
1246.It Cm \&:hash
1247Compute a 32-bit hash of the value and encode it as hex digits.
1248.It Cm \&:localtime[=utc]
1249The value is a format string for
1250.Xr strftime 3 ,
1251using
1252.Xr localtime 3 .
1253If a
1254.Va utc
1255value is not provided or is 0, the current time is used.
1256.It Cm \&:tA
1257Attempt to convert variable to an absolute path using
1258.Xr realpath 3 ,
1259if that fails, the value is unchanged.
1260.It Cm \&:tl
1261Converts variable to lower-case letters.
1262.It Cm \&:ts Ns Ar c
1263Words in the variable are normally separated by a space on expansion.
1264This modifier sets the separator to the character
1265.Ar c .
1266If
1267.Ar c
1268is omitted, then no separator is used.
1269The common escapes (including octal numeric codes), work as expected.
1270.It Cm \&:tu
1271Converts variable to upper-case letters.
1272.It Cm \&:tW
1273Causes the value to be treated as a single word
1274(possibly containing embedded white space).
1275See also
1276.Ql Cm \&:[*] .
1277.It Cm \&:tw
1278Causes the value to be treated as a sequence of
1279words delimited by white space.
1280See also
1281.Ql Cm \&:[@] .
1282.Sm off
1283.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1284.Sm on
1285Modify the first occurrence of
1286.Ar old_string
1287in the variable's value, replacing it with
1288.Ar new_string .
1289If a
1290.Ql g
1291is appended to the last slash of the pattern, all occurrences
1292in each word are replaced.
1293If a
1294.Ql 1
1295is appended to the last slash of the pattern, only the first word
1296is affected.
1297If a
1298.Ql W
1299is appended to the last slash of the pattern,
1300then the value is treated as a single word
1301(possibly containing embedded white space).
1302If
1303.Ar old_string
1304begins with a caret
1305.Pq Ql ^ ,
1306.Ar old_string
1307is anchored at the beginning of each word.
1308If
1309.Ar old_string
1310ends with a dollar sign
1311.Pq Ql \&$ ,
1312it is anchored at the end of each word.
1313Inside
1314.Ar new_string ,
1315an ampersand
1316.Pq Ql &
1317is replaced by
1318.Ar old_string
1319(without any
1320.Ql ^
1321or
1322.Ql \&$ ) .
1323Any character may be used as a delimiter for the parts of the modifier
1324string.
1325The anchoring, ampersand and delimiter characters may be escaped with a
1326backslash
1327.Pq Ql \e .
1328.Pp
1329Variable expansion occurs in the normal fashion inside both
1330.Ar old_string
1331and
1332.Ar new_string
1333with the single exception that a backslash is used to prevent the expansion
1334of a dollar sign
1335.Pq Ql \&$ ,
1336not a preceding dollar sign as is usual.
1337.Sm off
1338.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1339.Sm on
1340The
1341.Cm \&:C
1342modifier is just like the
1343.Cm \&:S
1344modifier except that the old and new strings, instead of being
1345simple strings, are an extended regular expression (see
1346.Xr regex 3 )
1347string
1348.Ar pattern
1349and an
1350.Xr ed 1 Ns \-style
1351string
1352.Ar replacement .
1353Normally, the first occurrence of the pattern
1354.Ar pattern
1355in each word of the value is substituted with
1356.Ar replacement .
1357The
1358.Ql 1
1359modifier causes the substitution to apply to at most one word; the
1360.Ql g
1361modifier causes the substitution to apply to as many instances of the
1362search pattern
1363.Ar pattern
1364as occur in the word or words it is found in; the
1365.Ql W
1366modifier causes the value to be treated as a single word
1367(possibly containing embedded white space).
1368Note that
1369.Ql 1
1370and
1371.Ql g
1372are orthogonal; the former specifies whether multiple words are
1373potentially affected, the latter whether multiple substitutions can
1374potentially occur within each affected word.
1375.Pp
1376As for the
1377.Cm \&:S
1378modifier, the
1379.Ar pattern
1380and
1381.Ar replacement
1382are subjected to variable expansion before being parsed as
1383regular expressions.
1384.It Cm \&:T
1385Replaces each word in the variable with its last component.
1386.It Cm \&:u
1387Remove adjacent duplicate words (like
1388.Xr uniq 1 ) .
1389.Sm off
1390.It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1391.Sm on
1392If the variable name (not its value), when parsed as a .if conditional
1393expression, evaluates to true, return as its value the
1394.Ar true_string ,
1395otherwise return the
1396.Ar false_string .
1397Since the variable name is used as the expression, \&:\&? must be the
1398first modifier after the variable name itself - which will, of course,
1399usually contain variable expansions.
1400A common error is trying to use expressions like
1401.Dl ${NUMBERS:M42:?match:no}
1402which actually tests defined(NUMBERS),
1403to determine is any words match "42" you need to use something like:
1404.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1405.It Ar :old_string=new_string
1406This is the
1407.At V
1408style variable substitution.
1409It must be the last modifier specified.
1410If
1411.Ar old_string
1412or
1413.Ar new_string
1414do not contain the pattern matching character
1415.Ar %
1416then it is assumed that they are
1417anchored at the end of each word, so only suffixes or entire
1418words may be replaced.
1419Otherwise
1420.Ar %
1421is the substring of
1422.Ar old_string
1423to be replaced in
1424.Ar new_string .
1425.Pp
1426Variable expansion occurs in the normal fashion inside both
1427.Ar old_string
1428and
1429.Ar new_string
1430with the single exception that a backslash is used to prevent the
1431expansion of a dollar sign
1432.Pq Ql \&$ ,
1433not a preceding dollar sign as is usual.
1434.Sm off
1435.It Cm \&:@ Ar temp Cm @ Ar string Cm @
1436.Sm on
1437This is the loop expansion mechanism from the OSF Development
1438Environment (ODE) make.
1439Unlike
1440.Cm \&.for
1441loops expansion occurs at the time of
1442reference.
1443Assign
1444.Ar temp
1445to each word in the variable and evaluate
1446.Ar string .
1447The ODE convention is that
1448.Ar temp
1449should start and end with a period.
1450For example.
1451.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1452.Pp
1453However a single character variable is often more readable:
1454.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1455.It Cm \&:_[=var]
1456Save the current variable value in
1457.Ql $_
1458or the named
1459.Va var
1460for later reference.
1461Example usage:
1462.Bd -literal -offset indent
1463M_cmpv.units = 1 1000 1000000
1464M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\
1465\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh
1466
1467.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}
1468
1469.Ed
1470Here
1471.Ql $_
1472is used to save the result of the
1473.Ql :S
1474modifier which is later referenced using the index values from
1475.Ql :range .
1476.It Cm \&:U Ns Ar newval
1477If the variable is undefined
1478.Ar newval
1479is the value.
1480If the variable is defined, the existing value is returned.
1481This is another ODE make feature.
1482It is handy for setting per-target CFLAGS for instance:
1483.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1484If a value is only required if the variable is undefined, use:
1485.Dl ${VAR:D:Unewval}
1486.It Cm \&:D Ns Ar newval
1487If the variable is defined
1488.Ar newval
1489is the value.
1490.It Cm \&:L
1491The name of the variable is the value.
1492.It Cm \&:P
1493The path of the node which has the same name as the variable
1494is the value.
1495If no such node exists or its path is null, then the
1496name of the variable is used.
1497In order for this modifier to work, the name (node) must at least have
1498appeared on the rhs of a dependency.
1499.Sm off
1500.It Cm \&:\&! Ar cmd Cm \&!
1501.Sm on
1502The output of running
1503.Ar cmd
1504is the value.
1505.It Cm \&:sh
1506If the variable is non-empty it is run as a command and the output
1507becomes the new value.
1508.It Cm \&::= Ns Ar str
1509The variable is assigned the value
1510.Ar str
1511after substitution.
1512This modifier and its variations are useful in
1513obscure situations such as wanting to set a variable when shell commands
1514are being parsed.
1515These assignment modifiers always expand to
1516nothing, so if appearing in a rule line by themselves should be
1517preceded with something to keep
1518.Nm
1519happy.
1520.Pp
1521The
1522.Ql Cm \&::
1523helps avoid false matches with the
1524.At V
1525style
1526.Cm \&:=
1527modifier and since substitution always occurs the
1528.Cm \&::=
1529form is vaguely appropriate.
1530.It Cm \&::?= Ns Ar str
1531As for
1532.Cm \&::=
1533but only if the variable does not already have a value.
1534.It Cm \&::+= Ns Ar str
1535Append
1536.Ar str
1537to the variable.
1538.It Cm \&::!= Ns Ar cmd
1539Assign the output of
1540.Ar cmd
1541to the variable.
1542.It Cm \&:\&[ Ns Ar range Ns Cm \&]
1543Selects one or more words from the value,
1544or performs other operations related to the way in which the
1545value is divided into words.
1546.Pp
1547Ordinarily, a value is treated as a sequence of words
1548delimited by white space.
1549Some modifiers suppress this behavior,
1550causing a value to be treated as a single word
1551(possibly containing embedded white space).
1552An empty value, or a value that consists entirely of white-space,
1553is treated as a single word.
1554For the purposes of the
1555.Ql Cm \&:[]
1556modifier, the words are indexed both forwards using positive integers
1557(where index 1 represents the first word),
1558and backwards using negative integers
1559(where index \-1 represents the last word).
1560.Pp
1561The
1562.Ar range
1563is subjected to variable expansion, and the expanded result is
1564then interpreted as follows:
1565.Bl -tag -width index
1566.\" :[n]
1567.It Ar index
1568Selects a single word from the value.
1569.\" :[start..end]
1570.It Ar start Ns Cm \&.. Ns Ar end
1571Selects all words from
1572.Ar start
1573to
1574.Ar end ,
1575inclusive.
1576For example,
1577.Ql Cm \&:[2..-1]
1578selects all words from the second word to the last word.
1579If
1580.Ar start
1581is greater than
1582.Ar end ,
1583then the words are output in reverse order.
1584For example,
1585.Ql Cm \&:[-1..1]
1586selects all the words from last to first.
1587.\" :[*]
1588.It Cm \&*
1589Causes subsequent modifiers to treat the value as a single word
1590(possibly containing embedded white space).
1591Analogous to the effect of
1592\&"$*\&"
1593in Bourne shell.
1594.\" :[0]
1595.It 0
1596Means the same as
1597.Ql Cm \&:[*] .
1598.\" :[*]
1599.It Cm \&@
1600Causes subsequent modifiers to treat the value as a sequence of words
1601delimited by white space.
1602Analogous to the effect of
1603\&"$@\&"
1604in Bourne shell.
1605.\" :[#]
1606.It Cm \&#
1607Returns the number of words in the value.
1608.El \" :[range]
1609.El
1610.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1611Makefile inclusion, conditional structures and for loops  reminiscent
1612of the C programming language are provided in
1613.Nm .
1614All such structures are identified by a line beginning with a single
1615dot
1616.Pq Ql \&.
1617character.
1618Files are included with either
1619.Cm \&.include Aq Ar file
1620or
1621.Cm \&.include Pf \*q Ar file Ns \*q .
1622Variables between the angle brackets or double quotes are expanded
1623to form the file name.
1624If angle brackets are used, the included makefile is expected to be in
1625the system makefile directory.
1626If double quotes are used, the including makefile's directory and any
1627directories specified using the
1628.Fl I
1629option are searched before the system
1630makefile directory.
1631For compatibility with other versions of
1632.Nm
1633.Ql include file ...
1634is also accepted.
1635.Pp
1636If the include statement is written as
1637.Cm .-include
1638or as
1639.Cm .sinclude
1640then errors locating and/or opening include files are ignored.
1641.Pp
1642If the include statement is written as
1643.Cm .dinclude
1644not only are errors locating and/or opening include files ignored,
1645but stale dependencies within the included file will be ignored
1646just like
1647.Va .MAKE.DEPENDFILE .
1648.Pp
1649Conditional expressions are also preceded by a single dot as the first
1650character of a line.
1651The possible conditionals are as follows:
1652.Bl -tag -width Ds
1653.It Ic .error Ar message
1654The message is printed along with the name of the makefile and line number,
1655then
1656.Nm
1657will exit.
1658.It Ic .export Ar variable ...
1659Export the specified global variable.
1660If no variable list is provided, all globals are exported
1661except for internal variables (those that start with
1662.Ql \&. ) .
1663This is not affected by the
1664.Fl X
1665flag, so should be used with caution.
1666For compatibility with other
1667.Nm
1668programs
1669.Ql export variable=value
1670is also accepted.
1671.Pp
1672Appending a variable name to
1673.Va .MAKE.EXPORTED
1674is equivalent to exporting a variable.
1675.It Ic .export-env Ar variable ...
1676The same as
1677.Ql .export ,
1678except that the variable is not appended to
1679.Va .MAKE.EXPORTED .
1680This allows exporting a value to the environment which is different from that
1681used by
1682.Nm
1683internally.
1684.It Ic .export-literal Ar variable ...
1685The same as
1686.Ql .export-env ,
1687except that variables in the value are not expanded.
1688.It Ic .info Ar message
1689The message is printed along with the name of the makefile and line number.
1690.It Ic .undef Ar variable
1691Un-define the specified global variable.
1692Only global variables may be un-defined.
1693.It Ic .unexport Ar variable ...
1694The opposite of
1695.Ql .export .
1696The specified global
1697.Va variable
1698will be removed from
1699.Va .MAKE.EXPORTED .
1700If no variable list is provided, all globals are unexported,
1701and
1702.Va .MAKE.EXPORTED
1703deleted.
1704.It Ic .unexport-env
1705Unexport all globals previously exported and
1706clear the environment inherited from the parent.
1707This operation will cause a memory leak of the original environment,
1708so should be used sparingly.
1709Testing for
1710.Va .MAKE.LEVEL
1711being 0, would make sense.
1712Also note that any variables which originated in the parent environment
1713should be explicitly preserved if desired.
1714For example:
1715.Bd -literal -offset indent
1716.Li .if ${.MAKE.LEVEL} == 0
1717PATH := ${PATH}
1718.Li .unexport-env
1719.Li .export PATH
1720.Li .endif
1721.Pp
1722.Ed
1723Would result in an environment containing only
1724.Ql Ev PATH ,
1725which is the minimal useful environment.
1726Actually
1727.Ql Ev .MAKE.LEVEL
1728will also be pushed into the new environment.
1729.It Ic .warning Ar message
1730The message prefixed by
1731.Ql Pa warning:
1732is printed along with the name of the makefile and line number.
1733.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1734Test the value of an expression.
1735.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1736Test the value of a variable.
1737.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1738Test the value of a variable.
1739.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1740Test the target being built.
1741.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1742Test the target being built.
1743.It Ic .else
1744Reverse the sense of the last conditional.
1745.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1746A combination of
1747.Ql Ic .else
1748followed by
1749.Ql Ic .if .
1750.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1751A combination of
1752.Ql Ic .else
1753followed by
1754.Ql Ic .ifdef .
1755.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1756A combination of
1757.Ql Ic .else
1758followed by
1759.Ql Ic .ifndef .
1760.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1761A combination of
1762.Ql Ic .else
1763followed by
1764.Ql Ic .ifmake .
1765.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1766A combination of
1767.Ql Ic .else
1768followed by
1769.Ql Ic .ifnmake .
1770.It Ic .endif
1771End the body of the conditional.
1772.El
1773.Pp
1774The
1775.Ar operator
1776may be any one of the following:
1777.Bl -tag -width "Cm XX"
1778.It Cm \&|\&|
1779Logical OR.
1780.It Cm \&&&
1781Logical
1782.Tn AND ;
1783of higher precedence than
1784.Dq \&|\&| .
1785.El
1786.Pp
1787As in C,
1788.Nm
1789will only evaluate a conditional as far as is necessary to determine
1790its value.
1791Parentheses may be used to change the order of evaluation.
1792The boolean operator
1793.Ql Ic \&!
1794may be used to logically negate an entire
1795conditional.
1796It is of higher precedence than
1797.Ql Ic \&&& .
1798.Pp
1799The value of
1800.Ar expression
1801may be any of the following:
1802.Bl -tag -width defined
1803.It Ic defined
1804Takes a variable name as an argument and evaluates to true if the variable
1805has been defined.
1806.It Ic make
1807Takes a target name as an argument and evaluates to true if the target
1808was specified as part of
1809.Nm Ns 's
1810command line or was declared the default target (either implicitly or
1811explicitly, see
1812.Va .MAIN )
1813before the line containing the conditional.
1814.It Ic empty
1815Takes a variable, with possible modifiers, and evaluates to true if
1816the expansion of the variable would result in an empty string.
1817.It Ic exists
1818Takes a file name as an argument and evaluates to true if the file exists.
1819The file is searched for on the system search path (see
1820.Va .PATH ) .
1821.It Ic target
1822Takes a target name as an argument and evaluates to true if the target
1823has been defined.
1824.It Ic commands
1825Takes a target name as an argument and evaluates to true if the target
1826has been defined and has commands associated with it.
1827.El
1828.Pp
1829.Ar Expression
1830may also be an arithmetic or string comparison.
1831Variable expansion is
1832performed on both sides of the comparison, after which the integral
1833values are compared.
1834A value is interpreted as hexadecimal if it is
1835preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1836The standard C relational operators are all supported.
1837If after
1838variable expansion, either the left or right hand side of a
1839.Ql Ic ==
1840or
1841.Ql Ic "!="
1842operator is not an integral value, then
1843string comparison is performed between the expanded
1844variables.
1845If no relational operator is given, it is assumed that the expanded
1846variable is being compared against 0 or an empty string in the case
1847of a string comparison.
1848.Pp
1849When
1850.Nm
1851is evaluating one of these conditional expressions, and it encounters
1852a (white-space separated) word it doesn't recognize, either the
1853.Dq make
1854or
1855.Dq defined
1856expression is applied to it, depending on the form of the conditional.
1857If the form is
1858.Ql Ic .ifdef ,
1859.Ql Ic .ifndef ,
1860or
1861.Ql Ic .if
1862the
1863.Dq defined
1864expression is applied.
1865Similarly, if the form is
1866.Ql Ic .ifmake
1867or
1868.Ql Ic .ifnmake , the
1869.Dq make
1870expression is applied.
1871.Pp
1872If the conditional evaluates to true the parsing of the makefile continues
1873as before.
1874If it evaluates to false, the following lines are skipped.
1875In both cases this continues until a
1876.Ql Ic .else
1877or
1878.Ql Ic .endif
1879is found.
1880.Pp
1881For loops are typically used to apply a set of rules to a list of files.
1882The syntax of a for loop is:
1883.Pp
1884.Bl -tag -compact -width Ds
1885.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1886.It Aq make-rules
1887.It Ic \&.endfor
1888.El
1889.Pp
1890After the for
1891.Ic expression
1892is evaluated, it is split into words.
1893On each iteration of the loop, one word is taken and assigned to each
1894.Ic variable ,
1895in order, and these
1896.Ic variables
1897are substituted into the
1898.Ic make-rules
1899inside the body of the for loop.
1900The number of words must come out even; that is, if there are three
1901iteration variables, the number of words provided must be a multiple
1902of three.
1903.Sh COMMENTS
1904Comments begin with a hash
1905.Pq Ql \&#
1906character, anywhere but in a shell
1907command line, and continue to the end of an unescaped new line.
1908.Sh SPECIAL SOURCES (ATTRIBUTES)
1909.Bl -tag -width .IGNOREx
1910.It Ic .EXEC
1911Target is never out of date, but always execute commands anyway.
1912.It Ic .IGNORE
1913Ignore any errors from the commands associated with this target, exactly
1914as if they all were preceded by a dash
1915.Pq Ql \- .
1916.\" .It Ic .INVISIBLE
1917.\" XXX
1918.\" .It Ic .JOIN
1919.\" XXX
1920.It Ic .MADE
1921Mark all sources of this target as being up-to-date.
1922.It Ic .MAKE
1923Execute the commands associated with this target even if the
1924.Fl n
1925or
1926.Fl t
1927options were specified.
1928Normally used to mark recursive
1929.Nm Ns s .
1930.It Ic .META
1931Create a meta file for the target, even if it is flagged as
1932.Ic .PHONY ,
1933.Ic .MAKE ,
1934or
1935.Ic .SPECIAL .
1936Usage in conjunction with
1937.Ic .MAKE
1938is the most likely case.
1939In "meta" mode, the target is out-of-date if the meta file is missing.
1940.It Ic .NOMETA
1941Do not create a meta file for the target.
1942Meta files are also not created for
1943.Ic .PHONY ,
1944.Ic .MAKE ,
1945or
1946.Ic .SPECIAL
1947targets.
1948.It Ic .NOMETA_CMP
1949Ignore differences in commands when deciding if target is out of date.
1950This is useful if the command contains a value which always changes.
1951If the number of commands change, though, the target will still be out of date.
1952The same effect applies to any command line that uses the variable
1953.Va .OODATE ,
1954which can be used for that purpose even when not otherwise needed or desired:
1955.Bd -literal -offset indent
1956
1957skip-compare-for-some:
1958	@echo this will be compared
1959	@echo this will not ${.OODATE:M.NOMETA_CMP}
1960	@echo this will also be compared
1961
1962.Ed
1963The
1964.Cm \&:M
1965pattern suppresses any expansion of the unwanted variable.
1966.It Ic .NOPATH
1967Do not search for the target in the directories specified by
1968.Ic .PATH .
1969.It Ic .NOTMAIN
1970Normally
1971.Nm
1972selects the first target it encounters as the default target to be built
1973if no target was specified.
1974This source prevents this target from being selected.
1975.It Ic .OPTIONAL
1976If a target is marked with this attribute and
1977.Nm
1978can't figure out how to create it, it will ignore this fact and assume
1979the file isn't needed or already exists.
1980.It Ic .PHONY
1981The target does not
1982correspond to an actual file; it is always considered to be out of date,
1983and will not be created with the
1984.Fl t
1985option.
1986Suffix-transformation rules are not applied to
1987.Ic .PHONY
1988targets.
1989.It Ic .PRECIOUS
1990When
1991.Nm
1992is interrupted, it normally removes any partially made targets.
1993This source prevents the target from being removed.
1994.It Ic .RECURSIVE
1995Synonym for
1996.Ic .MAKE .
1997.It Ic .SILENT
1998Do not echo any of the commands associated with this target, exactly
1999as if they all were preceded by an at sign
2000.Pq Ql @ .
2001.It Ic .USE
2002Turn the target into
2003.Nm Ns 's
2004version of a macro.
2005When the target is used as a source for another target, the other target
2006acquires the commands, sources, and attributes (except for
2007.Ic .USE )
2008of the
2009source.
2010If the target already has commands, the
2011.Ic .USE
2012target's commands are appended
2013to them.
2014.It Ic .USEBEFORE
2015Exactly like
2016.Ic .USE ,
2017but prepend the
2018.Ic .USEBEFORE
2019target commands to the target.
2020.It Ic .WAIT
2021If
2022.Ic .WAIT
2023appears in a dependency line, the sources that precede it are
2024made before the sources that succeed it in the line.
2025Since the dependents of files are not made until the file itself
2026could be made, this also stops the dependents being built unless they
2027are needed for another branch of the dependency tree.
2028So given:
2029.Bd -literal
2030x: a .WAIT b
2031	echo x
2032a:
2033	echo a
2034b: b1
2035	echo b
2036b1:
2037	echo b1
2038
2039.Ed
2040the output is always
2041.Ql a ,
2042.Ql b1 ,
2043.Ql b ,
2044.Ql x .
2045.br
2046The ordering imposed by
2047.Ic .WAIT
2048is only relevant for parallel makes.
2049.El
2050.Sh SPECIAL TARGETS
2051Special targets may not be included with other targets, i.e. they must be
2052the only target specified.
2053.Bl -tag -width .BEGINx
2054.It Ic .BEGIN
2055Any command lines attached to this target are executed before anything
2056else is done.
2057.It Ic .DEFAULT
2058This is sort of a
2059.Ic .USE
2060rule for any target (that was used only as a
2061source) that
2062.Nm
2063can't figure out any other way to create.
2064Only the shell script is used.
2065The
2066.Ic .IMPSRC
2067variable of a target that inherits
2068.Ic .DEFAULT Ns 's
2069commands is set
2070to the target's own name.
2071.It Ic .DELETE_ON_ERROR
2072If this target is present in the makefile, it globally causes make to
2073delete targets whose commands fail.
2074(By default, only targets whose commands are interrupted during
2075execution are deleted.
2076This is the historical behavior.)
2077This setting can be used to help prevent half-finished or malformed
2078targets from being left around and corrupting future rebuilds.
2079.It Ic .END
2080Any command lines attached to this target are executed after everything
2081else is done.
2082.It Ic .ERROR
2083Any command lines attached to this target are executed when another target fails.
2084The
2085.Ic .ERROR_TARGET
2086variable is set to the target that failed.
2087See also
2088.Ic MAKE_PRINT_VAR_ON_ERROR .
2089.It Ic .IGNORE
2090Mark each of the sources with the
2091.Ic .IGNORE
2092attribute.
2093If no sources are specified, this is the equivalent of specifying the
2094.Fl i
2095option.
2096.It Ic .INTERRUPT
2097If
2098.Nm
2099is interrupted, the commands for this target will be executed.
2100.It Ic .MAIN
2101If no target is specified when
2102.Nm
2103is invoked, this target will be built.
2104.It Ic .MAKEFLAGS
2105This target provides a way to specify flags for
2106.Nm
2107when the makefile is used.
2108The flags are as if typed to the shell, though the
2109.Fl f
2110option will have
2111no effect.
2112.\" XXX: NOT YET!!!!
2113.\" .It Ic .NOTPARALLEL
2114.\" The named targets are executed in non parallel mode.
2115.\" If no targets are
2116.\" specified, then all targets are executed in non parallel mode.
2117.It Ic .NOPATH
2118Apply the
2119.Ic .NOPATH
2120attribute to any specified sources.
2121.It Ic .NOTPARALLEL
2122Disable parallel mode.
2123.It Ic .NO_PARALLEL
2124Synonym for
2125.Ic .NOTPARALLEL ,
2126for compatibility with other pmake variants.
2127.It Ic .OBJDIR
2128The source is a new value for
2129.Ql Va .OBJDIR .
2130If it exists,
2131.Nm
2132will
2133.Xr chdir 2
2134to it and update the value of
2135.Ql Va .OBJDIR .
2136.It Ic .ORDER
2137The named targets are made in sequence.
2138This ordering does not add targets to the list of targets to be made.
2139Since the dependents of a target do not get built until the target itself
2140could be built, unless
2141.Ql a
2142is built by another part of the dependency graph,
2143the following is a dependency loop:
2144.Bd -literal
2145\&.ORDER: b a
2146b: a
2147.Ed
2148.Pp
2149The ordering imposed by
2150.Ic .ORDER
2151is only relevant for parallel makes.
2152.\" XXX: NOT YET!!!!
2153.\" .It Ic .PARALLEL
2154.\" The named targets are executed in parallel mode.
2155.\" If no targets are
2156.\" specified, then all targets are executed in parallel mode.
2157.It Ic .PATH
2158The sources are directories which are to be searched for files not
2159found in the current directory.
2160If no sources are specified, any previously specified directories are
2161deleted.
2162If the source is the special
2163.Ic .DOTLAST
2164target, then the current working
2165directory is searched last.
2166.It Ic .PATH. Ns Va suffix
2167Like
2168.Ic .PATH
2169but applies only to files with a particular suffix.
2170The suffix must have been previously declared with
2171.Ic .SUFFIXES .
2172.It Ic .PHONY
2173Apply the
2174.Ic .PHONY
2175attribute to any specified sources.
2176.It Ic .PRECIOUS
2177Apply the
2178.Ic .PRECIOUS
2179attribute to any specified sources.
2180If no sources are specified, the
2181.Ic .PRECIOUS
2182attribute is applied to every
2183target in the file.
2184.It Ic .SHELL
2185Sets the shell that
2186.Nm
2187will use to execute commands.
2188The sources are a set of
2189.Ar field=value
2190pairs.
2191.Bl -tag -width hasErrCtls
2192.It Ar name
2193This is the minimal specification, used to select one of the built-in
2194shell specs;
2195.Ar sh ,
2196.Ar ksh ,
2197and
2198.Ar csh .
2199.It Ar path
2200Specifies the path to the shell.
2201.It Ar hasErrCtl
2202Indicates whether the shell supports exit on error.
2203.It Ar check
2204The command to turn on error checking.
2205.It Ar ignore
2206The command to disable error checking.
2207.It Ar echo
2208The command to turn on echoing of commands executed.
2209.It Ar quiet
2210The command to turn off echoing of commands executed.
2211.It Ar filter
2212The output to filter after issuing the
2213.Ar quiet
2214command.
2215It is typically identical to
2216.Ar quiet .
2217.It Ar errFlag
2218The flag to pass the shell to enable error checking.
2219.It Ar echoFlag
2220The flag to pass the shell to enable command echoing.
2221.It Ar newline
2222The string literal to pass the shell that results in a single newline
2223character when used outside of any quoting characters.
2224.El
2225Example:
2226.Bd -literal
2227\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2228	check="set \-e" ignore="set +e" \e
2229	echo="set \-v" quiet="set +v" filter="set +v" \e
2230	echoFlag=v errFlag=e newline="'\en'"
2231.Ed
2232.It Ic .SILENT
2233Apply the
2234.Ic .SILENT
2235attribute to any specified sources.
2236If no sources are specified, the
2237.Ic .SILENT
2238attribute is applied to every
2239command in the file.
2240.It Ic .STALE
2241This target gets run when a dependency file contains stale entries, having
2242.Va .ALLSRC
2243set to the name of that dependency file.
2244.It Ic .SUFFIXES
2245Each source specifies a suffix to
2246.Nm .
2247If no sources are specified, any previously specified suffixes are deleted.
2248It allows the creation of suffix-transformation rules.
2249.Pp
2250Example:
2251.Bd -literal
2252\&.SUFFIXES: .o
2253\&.c.o:
2254	cc \-o ${.TARGET} \-c ${.IMPSRC}
2255.Ed
2256.El
2257.Sh ENVIRONMENT
2258.Nm
2259uses the following environment variables, if they exist:
2260.Ev MACHINE ,
2261.Ev MACHINE_ARCH ,
2262.Ev MAKE ,
2263.Ev MAKEFLAGS ,
2264.Ev MAKEOBJDIR ,
2265.Ev MAKEOBJDIRPREFIX ,
2266.Ev MAKESYSPATH ,
2267.Ev PWD ,
2268and
2269.Ev TMPDIR .
2270.Pp
2271.Ev MAKEOBJDIRPREFIX
2272and
2273.Ev MAKEOBJDIR
2274may only be set in the environment or on the command line to
2275.Nm
2276and not as makefile variables;
2277see the description of
2278.Ql Va .OBJDIR
2279for more details.
2280.Sh FILES
2281.Bl -tag -width /usr/share/mk -compact
2282.It .depend
2283list of dependencies
2284.It Makefile
2285list of dependencies
2286.It makefile
2287list of dependencies
2288.It sys.mk
2289system makefile
2290.It /usr/share/mk
2291system makefile directory
2292.El
2293.Sh COMPATIBILITY
2294The basic make syntax is compatible between different versions of make;
2295however the special variables, variable modifiers and conditionals are not.
2296.Ss Older versions
2297An incomplete list of changes in older versions of
2298.Nm :
2299.Pp
2300The way that .for loop variables are substituted changed after
2301NetBSD 5.0
2302so that they still appear to be variable expansions.
2303In particular this stops them being treated as syntax, and removes some
2304obscure problems using them in .if statements.
2305.Pp
2306The way that parallel makes are scheduled changed in
2307NetBSD 4.0
2308so that .ORDER and .WAIT apply recursively to the dependent nodes.
2309The algorithms used may change again in the future.
2310.Ss Other make dialects
2311Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
2312support most of the features of
2313.Nm
2314as described in this manual.
2315Most notably:
2316.Bl -bullet -offset indent
2317.It
2318The
2319.Ic .WAIT
2320and
2321.Ic .ORDER
2322declarations and most functionality pertaining to parallelization.
2323(GNU make supports parallelization but lacks these features needed to
2324control it effectively.)
2325.It
2326Directives, including for loops and conditionals and most of the
2327forms of include files.
2328(GNU make has its own incompatible and less powerful syntax for
2329conditionals.)
2330.It
2331All built-in variables that begin with a dot.
2332.It
2333Most of the special sources and targets that begin with a dot,
2334with the notable exception of
2335.Ic .PHONY ,
2336.Ic .PRECIOUS ,
2337and
2338.Ic .SUFFIXES .
2339.It
2340Variable modifiers, except for the
2341.Dl :old=new
2342string substitution, which does not portably support globbing with
2343.Ql %
2344and historically only works on declared suffixes.
2345.It
2346The
2347.Ic $>
2348variable even in its short form; most makes support this functionality
2349but its name varies.
2350.El
2351.Pp
2352Some features are somewhat more portable, such as assignment with
2353.Ic += ,
2354.Ic ?= ,
2355and
2356.Ic != .
2357The
2358.Ic .PATH
2359functionality is based on an older feature
2360.Ic VPATH
2361found in GNU make and many versions of SVR4 make; however,
2362historically its behavior is too ill-defined (and too buggy) to rely
2363upon.
2364.Pp
2365The
2366.Ic $@
2367and
2368.Ic $<
2369variables are more or less universally portable, as is the
2370.Ic $(MAKE)
2371variable.
2372Basic use of suffix rules (for files only in the current directory,
2373not trying to chain transformations together, etc.) is also reasonably
2374portable.
2375.Sh SEE ALSO
2376.Xr mkdep 1
2377.Sh HISTORY
2378.Nm
2379is derived from NetBSD
2380.Xr make 1 .
2381It uses autoconf to facilitate portability to other platforms.
2382.Pp
2383A
2384make
2385command appeared in
2386.At v7 .
2387This
2388make
2389implementation is based on Adam De Boor's pmake program which was written
2390for Sprite at Berkeley.
2391It was designed to be a parallel distributed make running jobs on different
2392machines using a daemon called
2393.Dq customs .
2394.Pp
2395Historically the target/dependency
2396.Dq FRC
2397has been used to FoRCe rebuilding (since the target/dependency
2398does not exist... unless someone creates an
2399.Dq FRC
2400file).
2401.Sh BUGS
2402The
2403make
2404syntax is difficult to parse without actually acting of the data.
2405For instance finding the end of a variable use should involve scanning each
2406the modifiers using the correct terminator for each field.
2407In many places
2408make
2409just counts {} and () in order to find the end of a variable expansion.
2410.Pp
2411There is no way of escaping a space character in a filename.
2412