 @@ -1,2069 +1,2072 @@
-.\"	$NetBSD: make.1,v 1.197 2011/11/13 18:18:35 dholland Exp $
+.\"	$NetBSD: make.1,v 1.198 2011/12/17 04:43:45 sjg Exp $
 .\"
 .\" Copyright (c) 1990, 1993
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
 .\" 3. Neither the name of the University nor the names of its contributors
 .\"    may be used to endorse or promote products derived from this software
 .\"    without specific prior written permission.
 .\"
 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
 .\"	from: @(#)make.1	8.4 (Berkeley) 3/19/94
 .\"
-.Dd November 6, 2011
+.Dd December 16, 2011
 .Dt MAKE 1
 .Os
 .Sh NAME
 .Nm make
 .Nd maintain program dependencies
 .Sh SYNOPSIS
 .Nm
 .Op Fl BeikNnqrstWX
 .Bk -words
 .Op Fl C Ar directory
 .Ek
 .Bk -words
 .Op Fl D Ar variable
 .Ek
 .Bk -words
 .Op Fl d Ar flags
 .Ek
 .Bk -words
 .Op Fl f Ar makefile
 .Ek
 .Bk -words
 .Op Fl I Ar directory
 .Ek
 .Bk -words
 .Op Fl J Ar private
 .Ek
 .Bk -words
 .Op Fl j Ar max_jobs
 .Ek
 .Bk -words
 .Op Fl m Ar directory
 .Ek
 .Bk -words
 .Op Fl T Ar file
 .Ek
 .Bk -words
 .Op Fl V Ar variable
 .Ek
 .Op Ar variable=value
 .Bk -words
 .Op Ar target ...
 .Ek
 .Sh DESCRIPTION
 .Nm
 is a program designed to simplify the maintenance of other programs.
 Its input is a list of specifications as to the files upon which programs
 and other files depend.
 If no
 .Fl f Ar makefile
 makefile option is given,
 .Nm
 will try to open
 .Ql Pa makefile
 then
 .Ql Pa Makefile
 in order to find the specifications.
 If the file
 .Ql Pa .depend
 exists, it is read (see
 .Xr mkdep 1 ) .
 .Pp
 This manual page is intended as a reference document only.
 For a more thorough description of
 .Nm
 and makefiles, please refer to
 .%T "PMake \- A Tutorial" .
 .Pp
 .Nm
 will prepend the contents of the
 .Va MAKEFLAGS
 environment variable to the command line arguments before parsing them.
 .Pp
 The options are as follows:
 .Bl -tag -width Ds
 .It Fl B
 Try to be backwards compatible by executing a single shell per command and
 by executing the commands to make the sources of a dependency line in sequence.
 .It Fl C Ar directory
 Change to
 .Ar directory
 before reading the makefiles or doing anything else.
 If multiple
 .Fl C
 options are specified, each is interpreted relative to the previous one:
 .Fl C Pa / Fl C Pa etc
 is equivalent to
 .Fl C Pa /etc .
 .It Fl D Ar variable
 Define
 .Ar variable
 to be 1, in the global context.
 .It Fl d Ar [-]flags
 Turn on debugging, and specify which portions of
 .Nm
 are to print debugging information.
 Unless the flags are preceded by
 .Ql \-
 they are added to the
 .Va MAKEFLAGS
 environment variable and will be processed by any child make processes.
 By default, debugging information is printed to standard error,
 but this can be changed using the
 .Ar F
 debugging flag.
 The debugging output is always unbuffered; in addition, if debugging
 is enabled but debugging output is not directed to standard output,
 then the standard output is line buffered.
 .Ar Flags
 is one or more of the following:
 .Bl -tag -width Ds
 .It Ar A
 Print all possible debugging information;
 equivalent to specifying all of the debugging flags.
 .It Ar a
 Print debugging information about archive searching and caching.
 .It Ar C
 Print debugging information about current working directory.
 .It Ar c
 Print debugging information about conditional evaluation.
 .It Ar d
 Print debugging information about directory searching and caching.
 .It Ar e
 Print debugging information about failed commands and targets.
 .It Ar F Ns Oo Sy \&+ Oc Ns Ar filename
 Specify where debugging output is written.
 This must be the last flag, because it consumes the remainder of
 the argument.
 If the character immediately after the
 .Ql F
 flag is
 .Ql \&+ ,
 then the file will be opened in append mode;
 otherwise the file will be overwritten.
 If the file name is
 .Ql stdout
 or
 .Ql stderr
 then debugging output will be written to the
 standard output or standard error output file descriptors respectively
 (and the
 .Ql \&+
 option has no effect).
 Otherwise, the output will be written to the named file.
 If the file name ends
 .Ql .%d
 then the
 .Ql %d
 is replaced by the pid.
 .It Ar f
 Print debugging information about loop evaluation.
 .It Ar "g1"
 Print the input graph before making anything.
 .It Ar "g2"
 Print the input graph after making everything, or before exiting
 on error.
 .It Ar "g3"
 Print the input graph before exiting on error.
 .It Ar j
 Print debugging information about running multiple shells.
 .It Ar l
 Print commands in Makefiles regardless of whether or not they are prefixed by
 .Ql @
 or other "quiet" flags.
 Also known as "loud" behavior.
 .It Ar M
 Print debugging information about "meta" mode decisions about targets.
 .It Ar m
 Print debugging information about making targets, including modification
 dates.
 .It Ar n
 Don't delete the temporary command scripts created when running commands.
 These temporary scripts are created in the directory
 referred to by the
 .Ev TMPDIR
 environment variable, or in
 .Pa /tmp
 if
 .Ev TMPDIR
 is unset or set to the empty string.
 The temporary scripts are created by
 .Xr mkstemp 3 ,
 and have names of the form
 .Pa makeXXXXXX .
 .Em NOTE :
 This can create many files in
 .Ev TMPDIR
 or
 .Pa /tmp ,
 so use with care.
 .It Ar p
 Print debugging information about makefile parsing.
 .It Ar s
 Print debugging information about suffix-transformation rules.
 .It Ar t
 Print debugging information about target list maintenance.
 .It Ar v
 Print debugging information about variable assignment.
 .It Ar x
 Run shell commands with
 .Fl x
 so the actual commands are printed as they are executed.
 .El
 .It Fl e
 Specify that environment variables override macro assignments within
 makefiles.
 .It Fl f Ar makefile
 Specify a makefile to read instead of the default
 .Ql Pa makefile .
 If
 .Ar makefile
 is
 .Ql Fl ,
 standard input is read.
 Multiple makefiles may be specified, and are read in the order specified.
 .It Fl I Ar directory
 Specify a directory in which to search for makefiles and included makefiles.
 The system makefile directory (or directories, see the
 .Fl m
 option) is automatically included as part of this list.
 .It Fl i
 Ignore non-zero exit of shell commands in the makefile.
 Equivalent to specifying
 .Ql Fl
 before each command line in the makefile.
 .It Fl J Ar private
 This option should
 .Em not
 be specified by the user.
 .Pp
 When the
 .Ar j
 option is in use in a recursive build, this option is passed by a make
 to child makes to allow all the make processes in the build to
 cooperate to avoid overloading the system.
 .It Fl j Ar max_jobs
 Specify the maximum number of jobs that
 .Nm
 may have running at any one time.
 The value is saved in
 .Va .MAKE.JOBS .
 Turns compatibility mode off, unless the
 .Ar B
 flag is also specified.
 When compatibility mode is off, all commands associated with a
 target are executed in a single shell invocation as opposed to the
 traditional one shell invocation per line.
 This can break traditional scripts which change directories on each
 command invocation and then expect to start with a fresh environment
 on the next line.
 It is more efficient to correct the scripts rather than turn backwards
 compatibility on.
 .It Fl k
 Continue processing after errors are encountered, but only on those targets
 that do not depend on the target whose creation caused the error.
 .It Fl m Ar directory
 Specify a directory in which to search for sys.mk and makefiles included
 via the
 .Ao Ar file Ac Ns -style
 include statement.
 The
 .Fl m
 option can be used multiple times to form a search path.
 This path will override the default system include path: /usr/share/mk.
 Furthermore the system include path will be appended to the search path used
 for
 .Qo Ar file Qc Ns -style
 include statements (see the
 .Fl I
 option).
 .Pp
 If a file or directory name in the
 .Fl m
 argument (or the
 .Ev MAKESYSPATH
 environment variable) starts with the string
 .Qq \&.../
 then
 .Nm
 will search for the specified file or directory named in the remaining part
 of the argument string.
 The search starts with the current directory of
 the Makefile and then works upward towards the root of the filesystem.
 If the search is successful, then the resulting directory replaces the
 .Qq \&.../
 specification in the
 .Fl m
 argument.
 If used, this feature allows
 .Nm
 to easily search in the current source tree for customized sys.mk files
 (e.g., by using
 .Qq \&.../mk/sys.mk
 as an argument).
 .It Fl n
 Display the commands that would have been executed, but do not
 actually execute them unless the target depends on the .MAKE special
 source (see below).
 .It Fl N
 Display the commands which would have been executed, but do not
 actually execute any of them; useful for debugging top-level makefiles
 without descending into subdirectories.
 .It Fl q
 Do not execute any commands, but exit 0 if the specified targets are
 up-to-date and 1, otherwise.
 .It Fl r
 Do not use the built-in rules specified in the system makefile.
 .It Fl s
 Do not echo any commands as they are executed.
 Equivalent to specifying
 .Ql Ic @
 before each command line in the makefile.
 .It Fl T Ar tracefile
 When used with the
 .Fl j
 flag,
 append a trace record to
 .Ar tracefile
 for each job started and completed.
 .It Fl t
 Rather than re-building a target as specified in the makefile, create it
 or update its modification time to make it appear up-to-date.
 .It Fl V Ar variable
 Print
 .Nm Ns 's
 idea of the value of
 .Ar variable ,
 in the global context.
 Do not build any targets.
 Multiple instances of this option may be specified;
 the variables will be printed one per line,
 with a blank line for each null or undefined variable.
 If
 .Ar variable
 contains a
 .Ql \&$
 then the value will be expanded before printing.
 .It Fl W
 Treat any warnings during makefile parsing as errors.
 .It Fl X
 Don't export variables passed on the command line to the environment
 individually.
 Variables passed on the command line are still exported
 via the
 .Va MAKEFLAGS
 environment variable.
 This option may be useful on systems which have a small limit on the
 size of command arguments.
 .It Ar variable=value
 Set the value of the variable
 .Ar variable
 to
 .Ar value .
 Normally, all values passed on the command line are also exported to
 sub-makes in the environment.
 The
 .Fl X
 flag disables this behavior.
 Variable assignments should follow options for POSIX compatibility
 but no ordering is enforced.
 .El
 .Pp
 There are seven different types of lines in a makefile: file dependency
 specifications, shell commands, variable assignments, include statements,
 conditional directives, for loops, and comments.
 .Pp
 In general, lines may be continued from one line to the next by ending
 them with a backslash
 .Pq Ql \e .
 The trailing newline character and initial whitespace on the following
 line are compressed into a single space.
 .Sh FILE DEPENDENCY SPECIFICATIONS
 Dependency lines consist of one or more targets, an operator, and zero
 or more sources.
 This creates a relationship where the targets
 .Dq depend
 on the sources
 and are usually created from them.
 The exact relationship between the target and the source is determined
 by the operator that separates them.
 The three operators are as follows:
 .Bl -tag -width flag
 .It Ic \&:
 A target is considered out-of-date if its modification time is less than
 those of any of its sources.
 Sources for a target accumulate over dependency lines when this operator
 is used.
 The target is removed if
 .Nm
 is interrupted.
 .It Ic \&!
 Targets are always re-created, but not until all sources have been
 examined and re-created as necessary.
 Sources for a target accumulate over dependency lines when this operator
 is used.
 The target is removed if
 .Nm
 is interrupted.
 .It Ic \&::
 If no sources are specified, the target is always re-created.
 Otherwise, a target is considered out-of-date if any of its sources has
 been modified more recently than the target.
 Sources for a target do not accumulate over dependency lines when this
 operator is used.
 The target will not be removed if
 .Nm
 is interrupted.
 .El
 .Pp
 Targets and sources may contain the shell wildcard values
 .Ql \&? ,
 .Ql * ,
 .Ql [] ,
 and
 .Ql {} .
 The values
 .Ql \&? ,
 .Ql * ,
 and
 .Ql []
 may only be used as part of the final
 component of the target or source, and must be used to describe existing
 files.
 The value
 .Ql {}
 need not necessarily be used to describe existing files.
 Expansion is in directory order, not alphabetically as done in the shell.
 .Sh SHELL COMMANDS
 Each target may have associated with it a series of shell commands, normally
 used to create the target.
 Each of the commands in this script
 .Em must
 be preceded by a tab.
 While any target may appear on a dependency line, only one of these
 dependencies may be followed by a creation script, unless the
 .Ql Ic \&::
 operator is used.
 .Pp
 If the first characters of the command line are any combination of
 .Ql Ic @ ,
 .Ql Ic + ,
 or
 .Ql Ic \- ,
 the command is treated specially.
+A
 .Ql Ic @
 causes the command not to be echoed before it is executed.
+A
 .Ql Ic +
 causes the command to be executed even when
 .Fl n
 is given.
 This is similar to the effect of the .MAKE special source,
 except that the effect can be limited to a single line of a script.
+A
 .Ql Ic \-
 causes any non-zero exit status of the command line to be ignored.
 .Sh VARIABLE ASSIGNMENTS
 Variables in make are much like variables in the shell, and, by tradition,
 consist of all upper-case letters.
 .Ss Variable assignment modifiers
 The five operators that can be used to assign values to variables are as
 follows:
 .Bl -tag -width Ds
 .It Ic \&=
 Assign the value to the variable.
 Any previous value is overridden.
 .It Ic \&+=
 Append the value to the current value of the variable.
 .It Ic \&?=
 Assign the value to the variable if it is not already defined.
 .It Ic \&:=
 Assign with expansion, i.e. expand the value before assigning it
 to the variable.
 Normally, expansion is not done until the variable is referenced.
 .Em NOTE :
 References to undefined variables are
 .Em not
 expanded.
 This can cause problems when variable modifiers are used.
 .It Ic \&!=
 Expand the value and pass it to the shell for execution and assign
 the result to the variable.
 Any newlines in the result are replaced with spaces.
 .El
 .Pp
 Any white-space before the assigned
 .Ar value
 is removed; if the value is being appended, a single space is inserted
 between the previous contents of the variable and the appended value.
 .Pp
 Variables are expanded by surrounding the variable name with either
 curly braces
 .Pq Ql {}
 or parentheses
 .Pq Ql ()
 and preceding it with
 a dollar sign
 .Pq Ql \&$ .
 If the variable name contains only a single letter, the surrounding
 braces or parentheses are not required.
 This shorter form is not recommended.
 .Pp
 If the variable name contains a dollar, then the name itself is expanded first.
 This allows almost arbitrary variable names, however names containing dollar,
 braces, parenthesis, or whitespace are really best avoided!
 .Pp
 If the result of expanding a variable contains a dollar sign
 .Pq Ql \&$
 the string is expanded again.
 .Pp
 Variable substitution occurs at three distinct times, depending on where
 the variable is being used.
 .Bl -enum
 .It
 Variables in dependency lines are expanded as the line is read.
 .It
 Variables in shell commands are expanded when the shell command is
 executed.
 .It
 .Dq .for
 loop index variables are expanded on each loop iteration.
 Note that other variables are not expanded inside loops so
 the following example code:
 .Bd -literal -offset indent
 .Dv .for i in 1 2 3
 a+=     ${i}
 j=      ${i}
 b+=     ${j}
 .Dv .endfor
 all:
 	@echo ${a}
 	@echo ${b}
 .Ed
 will print:
 .Bd -literal -offset indent
 2 3
 3 3
 .Ed
 Because while ${a} contains
 .Dq 1 2 3
 after the loop is executed, ${b}
 contains
 .Dq ${j} ${j} ${j}
 which expands to
 .Dq 3 3 3
 since after the loop completes ${j} contains
 .Dq 3 .
 .El
 .Ss Variable classes
 The four different classes of variables (in order of increasing precedence)
 are:
 .Bl -tag -width Ds
 .It Environment variables
 Variables defined as part of
 .Nm Ns 's
 environment.
 .It Global variables
 Variables defined in the makefile or in included makefiles.
 .It Command line variables
 Variables defined as part of the command line.
 .It Local variables
 Variables that are defined specific to a certain target.
 The seven local variables are as follows:
 .Bl -tag -width ".ARCHIVE"
 .It Va .ALLSRC
 The list of all sources for this target; also known as
 .Ql Va \&\*[Gt] .
 .It Va .ARCHIVE
 The name of the archive file.
 .It Va .IMPSRC
 In suffix-transformation rules, the name/path of the source from which the
 target is to be transformed (the
 .Dq implied
 source); also known as
 .Ql Va \&\*[Lt] .
 It is not defined in explicit rules.
 .It Va .MEMBER
 The name of the archive member.
 .It Va .OODATE
 The list of sources for this target that were deemed out-of-date; also
 known as
 .Ql Va \&? .
 .It Va .PREFIX
 The file prefix of the target, containing only the file portion, no suffix
 or preceding directory components; also known as
 .Ql Va * .
 .It Va .TARGET
 The name of the target; also known as
 .Ql Va @ .
 .El
 .Pp
 The shorter forms
 .Ql Va @ ,
 .Ql Va \&? ,
 .Ql Va \&\*[Lt] ,
 .Ql Va \&\*[Gt] ,
 and
 .Ql Va *
 are permitted for backward
 compatibility with historical makefiles and are not recommended.
 The six variables
 .Ql Va "@F" ,
 .Ql Va "@D" ,
 .Ql Va "\*[Lt]F" ,
 .Ql Va "\*[Lt]D" ,
 .Ql Va "*F" ,
 and
 .Ql Va "*D"
 are permitted for compatibility with
 .At V
 makefiles and are not recommended.
 .Pp
 Four of the local variables may be used in sources on dependency lines
 because they expand to the proper value for each target on the line.
 These variables are
 .Ql Va .TARGET ,
 .Ql Va .PREFIX ,
 .Ql Va .ARCHIVE ,
 and
 .Ql Va .MEMBER .
 .El
 .Ss Additional built-in variables
 In addition,
 .Nm
 sets or knows about the following variables:
 .Bl -tag -width .MAKEOVERRIDES
 .It Va \&$
 A single dollar sign
 .Ql \&$ ,
 i.e.
 .Ql \&$$
 expands to a single dollar
 sign.
 .It Va .ALLTARGETS
 The list of all targets encountered in the Makefile.
 If evaluated during
 Makefile parsing, lists only those targets encountered thus far.
 .It Va .CURDIR
 A path to the directory where
 .Nm
 was executed.
 Refer to the description of
 .Ql Ev PWD
 for more details.
 .It Ev MAKE
 The name that
 .Nm
 was executed with
 .Pq Va argv[0] .
 For compatibility
 .Nm
 also sets
 .Va .MAKE
 with the same value.
 The preferred variable to use is the environment variable
 .Ev MAKE
 because it is more compatible with other versions of
 .Nm
 and cannot be confused with the special target with the same name.
 .It Va .MAKE.DEPENDFILE
 Names the makefile (default
 .Ql Pa .depend )
 from which generated dependencies are read.
 .It Va .MAKE.EXPORTED
 The list of variables exported by
 .Nm .
 .It Va .MAKE.JOBS
 The argument to the
 .Fl j
 option.
 .It Va .MAKE.JOB.PREFIX
 If
 .Nm
 is run with
 .Ar j
 then output for each target is prefixed with a token
 .Ql --- target ---
 the first part of which can be controlled via
 .Va .MAKE.JOB.PREFIX .
 .br
 For example:
 .Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
 would produce tokens like
 .Ql ---make[1234] target ---
 making it easier to track the degree of parallelism being achieved.
 .It Ev MAKEFLAGS
 The environment variable
 .Ql Ev MAKEFLAGS
 may contain anything that
 may be specified on
 .Nm Ns 's
 command line.
 Anything specified on
 .Nm Ns 's
 command line is appended to the
 .Ql Ev MAKEFLAGS
 variable which is then
 entered into the environment for all programs which
 .Nm
 executes.
 .It Va .MAKE.LEVEL
 The recursion depth of
 .Nm .
 The initial instance of
 .Nm
 will be 0, and an incremented value is put into the environment
 to be seen by the next generation.
 This allows tests like:
 .Li .if ${.MAKE.LEVEL} == 0
 to protect things which should only be evaluated in the initial instance of
 .Nm .
 .It Va .MAKE.MAKEFILE_PREFERENCE
 The ordered list of makefile names
 (default
 .Ql Pa makefile ,
 .Ql Pa Makefile )
 that
 .Nm
 will look for.
 .It Va .MAKE.MAKEFILES
 The list of makefiles read by
 .Nm ,
 which is useful for tracking dependencies.
 Each makefile is recorded only once, regardless of the number of times read.
 .It Va .MAKE.MODE
 Processed after reading all makefiles.
 Can affect the mode that
 .Nm
 runs in.
 It can contain a number of keywords:
 .Bl -hang -width ignore-cmd
 .It Pa compat
 Like
 .Fl B ,
 puts
 .Nm
 into "compat" mode.
 .It Pa meta
 Puts
 .Nm
 into "meta" mode, where meta files are created for each target
 to capture the command run, the output generated and if
 .Xr filemon 4
 is available, the system calls which are of interest to
 .Nm .
 The captured output can be very useful when diagnosing errors.
 .It Pa curdirOk= Ar bf
 Normally
 .Nm
 will not create .meta files in
 .Ql Va .CURDIR .
 This can be overridden by setting
 .Va bf
 to a value which represents True.
 .It Pa verbose
 If in "meta" mode, print a clue about the target being built.
 This is useful if the build is otherwise running silently.
 The message printed the value of:
 .Va .MAKE.META.PREFIX .
 .It Pa ignore-cmd
 Some makefiles have commands which are simply not stable.
 This keyword causes them to be ignored for
 determining whether a target is out of date in "meta" mode.
 See also
 .Ic .NOMETA_CMP .
 .It Pa silent= Ar bf
 If
 .Va bf
 is True, when a .meta file is created, mark the target
 .El
 .It Va .MAKE.META.BAILIWICK
 In "meta" mode, provides a list of prefixes which
 match the directories controlled by
 .Nm .
 If a file that was generated outside of
 .Va .OBJDIR
 but within said bailiwick is missing,
 the current target is considered out-of-date.
 .It Va .MAKE.META.CREATED
 In "meta" mode, this variable contains a list of all the meta files
 updated.
 If not empty, it can be used to trigger processing of
 .Va .MAKE.META.FILES .
 .It Va .MAKE.META.FILES
 In "meta" mode, this variable contains a list of all the meta files
 used (updated or not).
 This list can be used to process the meta files to extract dependency
 information.
 .It Va .MAKE.META.PREFIX
 Defines the message printed for each meta file updated in "meta verbose" mode.
 The default value is:
 .Dl Building ${.TARGET:H:tA}/${.TARGET:T}
 .It Va .MAKEOVERRIDES
 This variable is used to record the names of variables assigned to
 on the command line, so that they may be exported as part of
 .Ql Ev MAKEFLAGS .
 This behaviour can be disabled by assigning an empty value to
 .Ql Va .MAKEOVERRIDES
 within a makefile.
 Extra variables can be exported from a makefile
 by appending their names to
 .Ql Va .MAKEOVERRIDES .
 .Ql Ev MAKEFLAGS
 is re-exported whenever
 .Ql Va .MAKEOVERRIDES
 is modified.
 .It Va .MAKE.PID
 The process-id of
 .Nm .
 .It Va .MAKE.PPID
 The parent process-id of
 .Nm .
 .It Va MAKE_PRINT_VAR_ON_ERROR
 When
 .Nm
 stops due to an error, it prints its name and the value of
 .Ql Va .CURDIR
 as well as the value of any variables named in
 .Ql Va MAKE_PRINT_VAR_ON_ERROR .
 .It Va .newline
 This variable is simply assigned a newline character as its value.
 This allows expansions using the
 .Cm \&:@
 modifier to put a newline between
 iterations of the loop rather than a space.
 For example, the printing of
 .Ql Va MAKE_PRINT_VAR_ON_ERROR
 could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
 .It Va .OBJDIR
 A path to the directory where the targets are built.
 Its value is determined by trying to
 .Xr chdir 2
 to the following directories in order and using the first match:
 .Bl -enum
 .It
 .Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
 .Pp
 (Only if
 .Ql Ev MAKEOBJDIRPREFIX
 is set in the environment or on the command line.)
 .It
 .Ev ${MAKEOBJDIR}
 .Pp
 (Only if
 .Ql Ev MAKEOBJDIR
 is set in the environment or on the command line.)
 .It
 .Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
 .It
 .Ev ${.CURDIR} Ns Pa /obj
 .It
 .Pa /usr/obj/ Ns Ev ${.CURDIR}
 .It
 .Ev ${.CURDIR}
 .El
 .Pp
 Variable expansion is performed on the value before it's used,
 so expressions such as
 .Dl ${.CURDIR:S,^/usr/src,/var/obj,}
 may be used.
 This is especially useful with
 .Ql Ev MAKEOBJDIR .
 .Pp
 .Ql Va .OBJDIR
 may be modified in the makefile as a global variable.
 In all cases,
 .Nm
 will
 .Xr chdir 2
 to
 .Ql Va .OBJDIR
 and set
 .Ql Ev PWD
 to that directory before executing any targets.
+.
 .It Va .PARSEDIR
 A path to the directory of the current
 .Ql Pa Makefile
 being parsed.
 .It Va .PARSEFILE
 The basename of the current
 .Ql Pa Makefile
 being parsed.
 This variable and
 .Ql Va .PARSEDIR
 are both set only while the
 .Ql Pa Makefiles
 are being parsed.
 If you want to retain their current values, assign them to a variable
 using assignment with expansion:
 .Pq Ql Cm \&:= .
 .It Va .PATH
 A variable that represents the list of directories that
 .Nm
 will search for files.
 The search list should be updated using the target
 .Ql Va .PATH
 rather than the variable.
 .It Ev PWD
 Alternate path to the current directory.
 .Nm
 normally sets
 .Ql Va .CURDIR
 to the canonical path given by
 .Xr getcwd 3 .
 However, if the environment variable
 .Ql Ev PWD
 is set and gives a path to the current directory, then
 .Nm
 sets
 .Ql Va .CURDIR
 to the value of
 .Ql Ev PWD
 instead.
 This behaviour is disabled if
 .Ql Ev MAKEOBJDIRPREFIX
 is set or
 .Ql Ev MAKEOBJDIR
 contains a variable transform.
 .Ql Ev PWD
 is set to the value of
 .Ql Va .OBJDIR
 for all programs which
 .Nm
 executes.
 .It Ev .TARGETS
 The list of targets explicitly specified on the command line, if any.
 .It Ev VPATH
 Colon-separated
 .Pq Dq \&:
 lists of directories that
 .Nm
 will search for files.
 The variable is supported for compatibility with old make programs only,
 use
 .Ql Va .PATH
 instead.
 .El
 .Ss Variable modifiers
 Variable expansion may be modified to select or modify each word of the
 variable (where a
 .Dq word
 is white-space delimited sequence of characters).
 The general format of a variable expansion is as follows:
 .Pp
 .Dl ${variable[:modifier[:...]]}
 .Pp
 Each modifier begins with a colon,
 which may be escaped with a backslash
 .Pq Ql \e .
 .Pp
 A set of modifiers can be specified via a variable, as follows:
 .Pp
 .Dl modifier_variable=modifier[:...]
 .Dl ${variable:${modifier_variable}[:...]}
 .Pp
 In this case the first modifier in the modifier_variable does not
 start with a colon, since that must appear in the referencing
 variable.
 If any of the modifiers in the modifier_variable contain a dollar sign
 .Pq Ql $ ,
 these must be doubled to avoid early expansion.
 .Pp
 The supported modifiers are:
 .Bl -tag -width EEE
 .It Cm \&:E
 Replaces each word in the variable with its suffix.
 .It Cm \&:H
 Replaces each word in the variable with everything but the last component.
 .It Cm \&:M Ns Ar pattern
 Select only those words that match
 .Ar pattern .
 The standard shell wildcard characters
 .Pf ( Ql * ,
 .Ql \&? ,
 and
 .Ql Oo Oc )
 may
 be used.
 The wildcard characters may be escaped with a backslash
 .Pq Ql \e .
 .It Cm \&:N Ns Ar pattern
 This is identical to
 .Ql Cm \&:M ,
 but selects all words which do not match
 .Ar pattern .
 .It Cm \&:O
 Order every word in variable alphabetically.
 To sort words in
 reverse order use the
 .Ql Cm \&:O:[-1..1]
 combination of modifiers.
 .It Cm \&:Ox
 Randomize words in variable.
 The results will be different each time you are referring to the
 modified variable; use the assignment with expansion
 .Pq Ql Cm \&:=
 to prevent such behaviour.
 For example,
 .Bd -literal -offset indent
 LIST=			uno due tre quattro
 RANDOM_LIST=		${LIST:Ox}
 STATIC_RANDOM_LIST:=	${LIST:Ox}
 all:
 	@echo "${RANDOM_LIST}"
 	@echo "${RANDOM_LIST}"
 	@echo "${STATIC_RANDOM_LIST}"
 	@echo "${STATIC_RANDOM_LIST}"
 .Ed
 may produce output similar to:
 .Bd -literal -offset indent
 quattro due tre uno
 tre due quattro uno
 due uno quattro tre
 due uno quattro tre
 .Ed
 .It Cm \&:Q
 Quotes every shell meta-character in the variable, so that it can be passed
 safely through recursive invocations of
 .Nm .
 .It Cm \&:R
 Replaces each word in the variable with everything but its suffix.
 .It Cm \&:gmtime
 The value is a format string for
 .Xr strftime 3 ,
 using the current
 .Xr gmtime 3 .
 .It Cm \&:hash
 Compute a 32bit hash of the value and encode it as hex digits.
 .It Cm \&:localtime
 The value is a format string for
 .Xr strftime 3 ,
 using the current
 .Xr localtime 3 .
 .It Cm \&:tA
 Attempt to convert variable to an absolute path using
 .Xr realpath 3 ,
 if that fails, the value is unchanged.
 .It Cm \&:tl
 Converts variable to lower-case letters.
 .It Cm \&:ts Ns Ar c
 Words in the variable are normally separated by a space on expansion.
 This modifier sets the separator to the character
 .Ar c .
 If
 .Ar c
 is omitted, then no separator is used.
 The common escapes (including octal numeric codes), work as expected.
 .It Cm \&:tu
 Converts variable to upper-case letters.
 .It Cm \&:tW
 Causes the value to be treated as a single word
 (possibly containing embedded white space).
 See also
 .Ql Cm \&:[*] .
 .It Cm \&:tw
 Causes the value to be treated as a sequence of
 words delimited by white space.
 See also
 .Ql Cm \&:[@] .
 .Sm off
 .It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
 .Sm on
 Modify the first occurrence of
 .Ar old_string
 in the variable's value, replacing it with
 .Ar new_string .
 If a
 .Ql g
 is appended to the last slash of the pattern, all occurrences
 in each word are replaced.
 If a
 .Ql 1
 is appended to the last slash of the pattern, only the first word
 is affected.
 If a
 .Ql W
 is appended to the last slash of the pattern,
 then the value is treated as a single word
 (possibly containing embedded white space).
 If
 .Ar old_string
 begins with a caret
 .Pq Ql ^ ,
 .Ar old_string
 is anchored at the beginning of each word.
 If
 .Ar old_string
 ends with a dollar sign
 .Pq Ql \&$ ,
 it is anchored at the end of each word.
 Inside
 .Ar new_string ,
 an ampersand
 .Pq Ql \*[Am]
 is replaced by
 .Ar old_string
 (without any
 .Ql ^
 or
 .Ql \&$ ) .
 Any character may be used as a delimiter for the parts of the modifier
 string.
 The anchoring, ampersand and delimiter characters may be escaped with a
 backslash
 .Pq Ql \e .
 .Pp
 Variable expansion occurs in the normal fashion inside both
 .Ar old_string
 and
 .Ar new_string
 with the single exception that a backslash is used to prevent the expansion
 of a dollar sign
 .Pq Ql \&$ ,
 not a preceding dollar sign as is usual.
 .Sm off
 .It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
 .Sm on
 The
 .Cm \&:C
 modifier is just like the
 .Cm \&:S
 modifier except that the old and new strings, instead of being
 simple strings, are a regular expression (see
 .Xr regex 3 )
 string
 .Ar pattern
 and an
 .Xr ed 1 Ns \-style
 string
 .Ar replacement .
 Normally, the first occurrence of the pattern
 .Ar pattern
 in each word of the value is substituted with
 .Ar replacement .
 The
 .Ql 1
 modifier causes the substitution to apply to at most one word; the
 .Ql g
 modifier causes the substitution to apply to as many instances of the
 search pattern
 .Ar pattern
 as occur in the word or words it is found in; the
 .Ql W
 modifier causes the value to be treated as a single word
 (possibly containing embedded white space).
 Note that
 .Ql 1
 and
 .Ql g
 are orthogonal; the former specifies whether multiple words are
 potentially affected, the latter whether multiple substitutions can
 potentially occur within each affected word.
 .It Cm \&:T
 Replaces each word in the variable with its last component.
 .It Cm \&:u
 Remove adjacent duplicate words (like
 .Xr uniq 1 ) .
 .Sm off
 .It Cm \&:\&? Ar true_string Cm \&: Ar false_string
 .Sm on
 If the variable name (not its value), when parsed as a .if conditional
 expression, evaluates to true, return as its value the
 .Ar true_string ,
 otherwise return the
 .Ar false_string .
 Since the variable name is used as the expression, \&:\&? must be the
 first modifier after the variable name itself - which will, of course,
 usually contain variable expansions.
 A common error is trying to use expressions like
 .Dl ${NUMBERS:M42:?match:no}
 which actually tests defined(NUMBERS),
 to determine is any words match "42" you need to use something like:
 .Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
 .It Ar :old_string=new_string
 This is the
 .At V
 style variable substitution.
 It must be the last modifier specified.
 If
 .Ar old_string
 or
 .Ar new_string
 do not contain the pattern matching character
 .Ar %
 then it is assumed that they are
 anchored at the end of each word, so only suffixes or entire
 words may be replaced.
 Otherwise
 .Ar %
 is the substring of
 .Ar old_string
 to be replaced in
 .Ar new_string .
 .Pp
 Variable expansion occurs in the normal fashion inside both
 .Ar old_string
 and
 .Ar new_string
 with the single exception that a backslash is used to prevent the
 expansion of a dollar sign
 .Pq Ql \&$ ,
 not a preceding dollar sign as is usual.
 .Sm off
 .It Cm \&:@ Ar temp Cm @ Ar string Cm @
 .Sm on
 This is the loop expansion mechanism from the OSF Development
 Environment (ODE) make.
 Unlike
 .Cm \&.for
 loops expansion occurs at the time of
 reference.
 Assign
 .Ar temp
 to each word in the variable and evaluate
 .Ar string .
 The ODE convention is that
 .Ar temp
 should start and end with a period.
 For example.
 .Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
 .Pp
 However a single character varaiable is often more readable:
 .Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
 .It Cm \&:U Ns Ar newval
 If the variable is undefined
 .Ar newval
 is the value.
 If the variable is defined, the existing value is returned.
 This is another ODE make feature.
 It is handy for setting per-target CFLAGS for instance:
 .Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
 If a value is only required if the variable is undefined, use:
 .Dl ${VAR:D:Unewval}
 .It Cm \&:D Ns Ar newval
 If the variable is defined
 .Ar newval
 is the value.
 .It Cm \&:L
 The name of the variable is the value.
 .It Cm \&:P
 The path of the node which has the same name as the variable
 is the value.
 If no such node exists or its path is null, then the
 name of the variable is used.
 .Sm off
 .It Cm \&:\&! Ar cmd Cm \&!
 .Sm on
 The output of running
 .Ar cmd
 is the value.
 .It Cm \&:sh
 If the variable is non-empty it is run as a command and the output
 becomes the new value.
 .It Cm \&::= Ns Ar str
 The variable is assigned the value
 .Ar str
 after substitution.
 This modifier and its variations are useful in
 obscure situations such as wanting to set a variable when shell commands
 are being parsed.
 These assignment modifiers always expand to
 nothing, so if appearing in a rule line by themselves should be
 preceded with something to keep
 .Nm
 happy.
 .Pp
 The
 .Ql Cm \&::
 helps avoid false matches with the
 .At V
 style
 .Cm \&:=
 modifier and since substitution always occurs the
 .Cm \&::=
 form is vaguely appropriate.
 .It Cm \&::?= Ns Ar str
 As for
 .Cm \&::=
 but only if the variable does not already have a value.
 .It Cm \&::+= Ns Ar str
 Append
 .Ar str
 to the variable.
 .It Cm \&::!= Ns Ar cmd
 Assign the output of
 .Ar cmd
 to the variable.
 .It Cm \&:\&[ Ns Ar range Ns Cm \&]
 Selects one or more words from the value,
 or performs other operations related to the way in which the
 value is divided into words.
 .Pp
 Ordinarily, a value is treated as a sequence of words
 delimited by white space.
 Some modifiers suppress this behaviour,
 causing a value to be treated as a single word
 (possibly containing embedded white space).
 An empty value, or a value that consists entirely of white-space,
 is treated as a single word.
 For the purposes of the
 .Ql Cm \&:[]
 modifier, the words are indexed both forwards using positive integers
 (where index 1 represents the first word),
 and backwards using negative integers
 (where index \-1 represents the last word).
 .Pp
 The
 .Ar range
 is subjected to variable expansion, and the expanded result is
 then interpreted as follows:
 .Bl -tag -width index
 .\" :[n]
 .It Ar index
 Selects a single word from the value.
 .\" :[start..end]
 .It Ar start Ns Cm \&.. Ns Ar end
 Selects all words from
 .Ar start
 to
 .Ar end ,
 inclusive.
 For example,
 .Ql Cm \&:[2..-1]
 selects all words from the second word to the last word.
 If
 .Ar start
 is greater than
 .Ar end ,
 then the words are output in reverse order.
 For example,
 .Ql Cm \&:[-1..1]
 selects all the words from last to first.
 .\" :[*]
 .It Cm \&*
 Causes subsequent modifiers to treat the value as a single word
 (possibly containing embedded white space).
 Analogous to the effect of
 \&"$*\&"
 in Bourne shell.
 .\" :[0]
 .It 0
 Means the same as
 .Ql Cm \&:[*] .
 .\" :[*]
 .It Cm \&@
 Causes subsequent modifiers to treat the value as a sequence of words
 delimited by white space.
 Analogous to the effect of
 \&"$@\&"
 in Bourne shell.
 .\" :[#]
 .It Cm \&#
 Returns the number of words in the value.
 .El \" :[range]
 .El
 .Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
 Makefile inclusion, conditional structures and for loops  reminiscent
 of the C programming language are provided in
 .Nm .
 All such structures are identified by a line beginning with a single
 dot
 .Pq Ql \&.
 character.
 Files are included with either
 .Cm \&.include Aq Ar file
 or
 .Cm \&.include Pf \*q Ar file Ns \*q .
 Variables between the angle brackets or double quotes are expanded
 to form the file name.
 If angle brackets are used, the included makefile is expected to be in
 the system makefile directory.
 If double quotes are used, the including makefile's directory and any
 directories specified using the
 .Fl I
 option are searched before the system
 makefile directory.
 For compatibility with other versions of
 .Nm
 .Ql include file ...
 is also accepted.
 If the include statement is written as
 .Cm .-include
 or as
 .Cm .sinclude
 then errors locating and/or opening include files are ignored.
 .Pp
 Conditional expressions are also preceded by a single dot as the first
 character of a line.
 The possible conditionals are as follows:
 .Bl -tag -width Ds
 .It Ic .error Ar message
 The message is printed along with the name of the makefile and line number,
 then
 .Nm
 will exit.
 .It Ic .export Ar variable ...
 Export the specified global variable.
 If no variable list is provided, all globals are exported
 except for internal variables (those that start with
 .Ql \&. ) .
 This is not affected by the
 .Fl X
 flag, so should be used with caution.
 .Pp
 Appending a variable name to
 .Va .MAKE.EXPORTED
 is equivalent to exporting a variable.
 .It Ic .export-env Ar variable ...
 The same as
 .Ql .export ,
 except that the variable is not appended to
 .Va .MAKE.EXPORTED .
 This allows exporting a value to the environment which is different from that
 used by
 .Nm
 internally.
 .It Ic .info Ar message
 The message is printed along with the name of the makefile and line number.
 .It Ic .undef Ar variable
 Un-define the specified global variable.
 Only global variables may be un-defined.
 .It Ic .unexport Ar variable ...
 The opposite of
 .Ql .export .
 The specified global
 .Va variable
 will be removed from
 .Va .MAKE.EXPORTED .
 If no variable list is provided, all globals are unexported,
 and
 .Va .MAKE.EXPORTED
 deleted.
 .It Ic .unexport-env
 Unexport all globals previously exported and
 clear the environment inherited from the parent.
 This operation will cause a memory leak of the original environment,
 so should be used sparingly.
 Testing for
 .Va .MAKE.LEVEL
 being 0, would make sense.
 Also note that any variables which originated in the parent environment
 should be explicitly preserved if desired.
 For example:
 .Bd -literal -offset indent
 .Li .if ${.MAKE.LEVEL} == 0
 PATH := ${PATH}
 .Li .unexport-env
 .Li .export PATH
 .Li .endif
 .Pp
 .Ed
 Would result in an environment containing only
 .Ql Ev PATH ,
 which is the minimal useful environment.
 Actually
 .Ql Ev .MAKE.LEVEL
 will also be pushed into the new environment.
 .It Ic .warning Ar message
 The message prefixed by
 .Ql Pa warning:
 is printed along with the name of the makefile and line number.
 .It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
 Test the value of an expression.
 .It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
 Test the value of a variable.
 .It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
 Test the value of a variable.
 .It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
 Test the target being built.
 .It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
 Test the target being built.
 .It Ic .else
 Reverse the sense of the last conditional.
 .It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
 A combination of
 .Ql Ic .else
 followed by
 .Ql Ic .if .
 .It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
 A combination of
 .Ql Ic .else
 followed by
 .Ql Ic .ifdef .
 .It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
 A combination of
 .Ql Ic .else
 followed by
 .Ql Ic .ifndef .
 .It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
 A combination of
 .Ql Ic .else
 followed by
 .Ql Ic .ifmake .
 .It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
 A combination of
 .Ql Ic .else
 followed by
 .Ql Ic .ifnmake .
 .It Ic .endif
 End the body of the conditional.
 .El
 .Pp
 The
 .Ar operator
 may be any one of the following:
 .Bl -tag -width "Cm XX"
 .It Cm \&|\&|
 Logical OR.
 .It Cm \&\*[Am]\*[Am]
 Logical
 .Tn AND ;
 of higher precedence than
 .Dq \&|\&| .
 .El
 .Pp
 As in C,
 .Nm
 will only evaluate a conditional as far as is necessary to determine
 its value.
 Parentheses may be used to change the order of evaluation.
 The boolean operator
 .Ql Ic \&!
 may be used to logically negate an entire
 conditional.
 It is of higher precedence than
 .Ql Ic \&\*[Am]\*[Am] .
 .Pp
 The value of
 .Ar expression
 may be any of the following:
 .Bl -tag -width defined
 .It Ic defined
 Takes a variable name as an argument and evaluates to true if the variable
 has been defined.
 .It Ic make
 Takes a target name as an argument and evaluates to true if the target
 was specified as part of
 .Nm Ns 's
 command line or was declared the default target (either implicitly or
 explicitly, see
 .Va .MAIN )
 before the line containing the conditional.
 .It Ic empty
 Takes a variable, with possible modifiers, and evaluates to true if
 the expansion of the variable would result in an empty string.
 .It Ic exists
 Takes a file name as an argument and evaluates to true if the file exists.
 The file is searched for on the system search path (see
 .Va .PATH ) .
 .It Ic target
 Takes a target name as an argument and evaluates to true if the target
 has been defined.
 .It Ic commands
 Takes a target name as an argument and evaluates to true if the target
 has been defined and has commands associated with it.
 .El
 .Pp
 .Ar Expression
 may also be an arithmetic or string comparison.
 Variable expansion is
 performed on both sides of the comparison, after which the integral
 values are compared.
 A value is interpreted as hexadecimal if it is
 preceded by 0x, otherwise it is decimal; octal numbers are not supported.
 The standard C relational operators are all supported.
 If after
 variable expansion, either the left or right hand side of a
 .Ql Ic ==
 or
 .Ql Ic "!="
 operator is not an integral value, then
 string comparison is performed between the expanded
 variables.
 If no relational operator is given, it is assumed that the expanded
 variable is being compared against 0 or an empty string in the case
 of a string comparison.
 .Pp
 When
 .Nm
 is evaluating one of these conditional expressions, and it encounters
 a (white-space separated) word it doesn't recognize, either the
 .Dq make
 or
 .Dq defined
 expression is applied to it, depending on the form of the conditional.
 If the form is
 .Ql Ic .ifdef ,
 .Ql Ic .ifndef ,
 or
 .Ql Ic .if
 the
 .Dq defined
 expression is applied.
 Similarly, if the form is
 .Ql Ic .ifmake
 or
 .Ql Ic .ifnmake , the
 .Dq make
 expression is applied.
 .Pp
 If the conditional evaluates to true the parsing of the makefile continues
 as before.
 If it evaluates to false, the following lines are skipped.
 In both cases this continues until a
 .Ql Ic .else
 or
 .Ql Ic .endif
 is found.
 .Pp
 For loops are typically used to apply a set of rules to a list of files.
 The syntax of a for loop is:
 .Pp
 .Bl -tag -compact -width Ds
 .It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
 .It Aq make-rules
 .It Ic \&.endfor
 .El
 .Pp
 After the for
 .Ic expression
 is evaluated, it is split into words.
 On each iteration of the loop, one word is taken and assigned to each
 .Ic variable ,
 in order, and these
 .Ic variables
 are substituted into the
 .Ic make-rules
 inside the body of the for loop.
 The number of words must come out even; that is, if there are three
 iteration variables, the number of words provided must be a multiple
 of three.
 .Sh COMMENTS
 Comments begin with a hash
 .Pq Ql \&#
 character, anywhere but in a shell
 command line, and continue to the end of an unescaped new line.
 .Sh SPECIAL SOURCES (ATTRIBUTES)
 .Bl -tag -width .IGNOREx
 .It Ic .EXEC
 Target is never out of date, but always execute commands anyway.
 .It Ic .IGNORE
 Ignore any errors from the commands associated with this target, exactly
 as if they all were preceded by a dash
 .Pq Ql \- .
 .\" .It Ic .INVISIBLE
 .\" XXX
 .\" .It Ic .JOIN
 .\" XXX
 .It Ic .MADE
 Mark all sources of this target as being up-to-date.
 .It Ic .MAKE
 Execute the commands associated with this target even if the
 .Fl n
 or
 .Fl t
 options were specified.
 Normally used to mark recursive
 .Nm Ns 's .
 .It Ic .META
 Create a meta file for the target, even if it is flagged as
 .Ic .PHONY ,
 .Ic .MAKE ,
 or
 .Ic .SPECIAL .
 Usage in conjunction with
 .Ic .MAKE
 is the most likely case.
 In "meta" mode, the target is out-of-date if the meta file is missing.
 .It Ic .NOMETA
 Do not create a meta file for the target.
 Meta files are also not created for
 .Ic .PHONY ,
 .Ic .MAKE ,
 or
 .Ic .SPECIAL
 targets.
 .It Ic .NOMETA_CMP
 Ignore differences in commands when deciding if target is out of date.
 This is useful if the command contains a value which always changes.
 If the number of commands change, though, the target will still be out of date.
 .It Ic .NOPATH
 Do not search for the target in the directories specified by
 .Ic .PATH .
 .It Ic .NOTMAIN
 Normally
 .Nm
 selects the first target it encounters as the default target to be built
 if no target was specified.
 This source prevents this target from being selected.
 .It Ic .OPTIONAL
 If a target is marked with this attribute and
 .Nm
 can't figure out how to create it, it will ignore this fact and assume
 the file isn't needed or already exists.
 .It Ic .PHONY
 The target does not
 correspond to an actual file; it is always considered to be out of date,
 and will not be created with the
 .Fl t
 option.
 Suffix-transformation rules are not applied to
 .Ic .PHONY
 targets.
 .It Ic .PRECIOUS
 When
 .Nm
 is interrupted, it normally removes any partially made targets.
 This source prevents the target from being removed.
 .It Ic .RECURSIVE
 Synonym for
 .Ic .MAKE .
 .It Ic .SILENT
 Do not echo any of the commands associated with this target, exactly
 as if they all were preceded by an at sign
 .Pq Ql @ .
 .It Ic .USE
 Turn the target into
 .Nm Ns 's
 version of a macro.
 When the target is used as a source for another target, the other target
 acquires the commands, sources, and attributes (except for
 .Ic .USE )
 of the
 source.
 If the target already has commands, the
 .Ic .USE
 target's commands are appended
 to them.
 .It Ic .USEBEFORE
 Exactly like
 .Ic .USE ,
 but prepend the
 .Ic .USEBEFORE
 target commands to the target.
 .It Ic .WAIT
 If
 .Ic .WAIT
 appears in a dependency line, the sources that precede it are
 made before the sources that succeed it in the line.
 Since the dependents of files are not made until the file itself
 could be made, this also stops the dependents being built unless they
 are needed for another branch of the dependency tree.
 So given:
 .Bd -literal
 x: a .WAIT b
 	echo x
 a:
 	echo a
 b: b1
 	echo b
 b1:
 	echo b1
 .Ed
 the output is always
 .Ql a ,
 .Ql b1 ,
 .Ql b ,
 .Ql x .
 .br
 The ordering imposed by
 .Ic .WAIT
 is only relevant for parallel makes.
 .El
 .Sh SPECIAL TARGETS
 Special targets may not be included with other targets, i.e. they must be
 the only target specified.
 .Bl -tag -width .BEGINx
 .It Ic .BEGIN
 Any command lines attached to this target are executed before anything
 else is done.
 .It Ic .DEFAULT
 This is sort of a
 .Ic .USE
 rule for any target (that was used only as a
 source) that
 .Nm
 can't figure out any other way to create.
 Only the shell script is used.
 The
 .Ic .IMPSRC
 variable of a target that inherits
 .Ic .DEFAULT Ns 's
 commands is set
 to the target's own name.
 .It Ic .END
 Any command lines attached to this target are executed after everything
 else is done.
 .It Ic .ERROR
 Any command lines attached to this target are executed when another target fails.
 The
 .Ic .ERROR_TARGET
 variable is set to the target that failed.
 See also
 .Ic MAKE_PRINT_VAR_ON_ERROR .
 .It Ic .IGNORE
 Mark each of the sources with the
 .Ic .IGNORE
 attribute.
 If no sources are specified, this is the equivalent of specifying the
 .Fl i
 option.
 .It Ic .INTERRUPT
 If
 .Nm
 is interrupted, the commands for this target will be executed.
 .It Ic .MAIN
 If no target is specified when
 .Nm
 is invoked, this target will be built.
 .It Ic .MAKEFLAGS
 This target provides a way to specify flags for
 .Nm
 when the makefile is used.
 The flags are as if typed to the shell, though the
 .Fl f
 option will have
 no effect.
 .\" XXX: NOT YET!!!!
 .\" .It Ic .NOTPARALLEL
 .\" The named targets are executed in non parallel mode.
 .\" If no targets are
 .\" specified, then all targets are executed in non parallel mode.
 .It Ic .NOPATH
 Apply the
 .Ic .NOPATH
 attribute to any specified sources.
 .It Ic .NOTPARALLEL
 Disable parallel mode.
 .It Ic .NO_PARALLEL
 Synonym for
 .Ic .NOTPARALLEL ,
 for compatibility with other pmake variants.
 .It Ic .ORDER
 The named targets are made in sequence.
 This ordering does not add targets to the list of targets to be made.
 Since the dependents of a target do not get built until the target itself
 could be built, unless
 .Ql a
 is built by another part of the dependency graph,
 the following is a dependency loop:
 .Bd -literal
 \&.ORDER: b a
 b: a
 .Ed
 .Pp
 The ordering imposed by
 .Ic .ORDER
 is only relevant for parallel makes.
 .\" XXX: NOT YET!!!!
 .\" .It Ic .PARALLEL
 .\" The named targets are executed in parallel mode.
 .\" If no targets are
 .\" specified, then all targets are executed in parallel mode.
 .It Ic .PATH
 The sources are directories which are to be searched for files not
 found in the current directory.
 If no sources are specified, any previously specified directories are
 deleted.
 If the source is the special
 .Ic .DOTLAST
 target, then the current working
 directory is searched last.
 .It Ic .PHONY
 Apply the
 .Ic .PHONY
 attribute to any specified sources.
 .It Ic .PRECIOUS
 Apply the
 .Ic .PRECIOUS
 attribute to any specified sources.
 If no sources are specified, the
 .Ic .PRECIOUS
 attribute is applied to every
 target in the file.
 .It Ic .SHELL
 Sets the shell that
 .Nm
 will use to execute commands.
 The sources are a set of
 .Ar field=value
 pairs.
 .Bl -tag -width hasErrCtls
 .It Ar name
 This is the minimal specification, used to select one of the builtin
 shell specs;
 .Ar sh ,
 .Ar ksh ,
 and
 .Ar csh .
 .It Ar path
 Specifies the path to the shell.
 .It Ar hasErrCtl
 Indicates whether the shell supports exit on error.
 .It Ar check
 The command to turn on error checking.
 .It Ar ignore
 The command to disable error checking.
 .It Ar echo
 The command to turn on echoing of commands executed.
 .It Ar quiet
 The command to turn off echoing of commands executed.
 .It Ar filter
 The output to filter after issuing the
 .Ar quiet
 command.
 It is typically identical to
 .Ar quiet .
 .It Ar errFlag
 The flag to pass the shell to enable error checking.
 .It Ar echoFlag
 The flag to pass the shell to enable command echoing.
 .It Ar newline
 The string literal to pass the shell that results in a single newline
 character when used outside of any quoting characters.
 .El
 Example:
 .Bd -literal
 \&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
 	check="set \-e" ignore="set +e" \e
 	echo="set \-v" quiet="set +v" filter="set +v" \e
 	echoFlag=v errFlag=e newline="'\en'"
 .Ed
 .It Ic .SILENT
 Apply the
 .Ic .SILENT
 attribute to any specified sources.
 If no sources are specified, the
 .Ic .SILENT
 attribute is applied to every
 command in the file.
 .It Ic .SUFFIXES
 Each source specifies a suffix to
 .Nm .
 If no sources are specified, any previously specified suffixes are deleted.
 It allows the creation of suffix-transformation rules.
 .Pp
 Example:
 .Bd -literal
 \&.SUFFIXES: .o
 \&.c.o:
 	cc \-o ${.TARGET} \-c ${.IMPSRC}
 .Ed
 .El
 .Sh ENVIRONMENT
 .Nm
 uses the following environment variables, if they exist:
 .Ev MACHINE ,
 .Ev MACHINE_ARCH ,
 .Ev MAKE ,
 .Ev MAKEFLAGS ,
 .Ev MAKEOBJDIR ,
 .Ev MAKEOBJDIRPREFIX ,
 .Ev MAKESYSPATH ,
 .Ev PWD ,
 and
 .Ev TMPDIR .
 .Pp
 .Ev MAKEOBJDIRPREFIX
 and
 .Ev MAKEOBJDIR
 may only be set in the environment or on the command line to
 .Nm
 and not as makefile variables;
 see the description of
 .Ql Va .OBJDIR
 for more details.
 .Sh FILES
 .Bl -tag -width /usr/share/mk -compact
 .It .depend
 list of dependencies
 .It Makefile
 list of dependencies
 .It makefile
 list of dependencies
 .It sys.mk
 system makefile
 .It /usr/share/mk
 system makefile directory
 .El
 .Sh COMPATIBILITY
 The basic make syntax is compatible between different versions of make,
 however the special variables, variable modifiers and conditionals are not.
 .Pp
 The way that parallel makes are scheduled changed in
 .Nx 4.0
 so that .ORDER and .WAIT apply recursively to the dependent nodes.
 The algorithms used may change again in the future.
 .Pp
 The way that .for loop variables are substituted changed after
 .Nx 5.0
 so that they still appear to be variable expansions.
 In particular this stops them being treated as syntax, and removes some
 obscure problems using them in .if statements.
 .Pp
 Unlike other
 .Nm
 programs, this implementation by default executes all commands for a given
 target using a single shell invocation.
 This is done for both efficiency and to simplify error handling in remote
 command invocations.
 Typically this is transparent to the user, unless the target commands change
 the current working directory using
 .Dq cd
 or
 .Dq chdir .
 To be compatible with Makefiles that do this, one can use
 .Fl B
 to disable this behavior.
 .Sh SEE ALSO
 .Xr mkdep 1
 .Sh HISTORY
+A
 .Nm
 command appeared in
 .At v7 .
 This
 .Nm
 implementation is based on Adam De Boor's pmake program which was written
 for Sprint at Berkeley.
 It was designed to be a parallel distributed make running jobs on different
 machines using a daemon called
 .Dq customs .
 .Sh BUGS
 The
 .Nm
 syntax is difficult to parse without actually acting of the data.
 For instance finding the end of a variable use should involve scanning each
 the modifiers using the correct terminator for each field.
 In many places
 .Nm
 just counts {} and () in order to find the end of a variable expansion.
 .Pp
 There is no way of escaping a space character in a filename.