\"      $NetBSD: make.1,v 1.386 2025/06/28 19:42:31 rillig Exp $
\"
\" Copyright (c) 1990, 1993
\"      The Regents of the University of California.  All rights reserved.
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\" 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.
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\" 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
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\"      from: @(#)make.1        8.4 (Berkeley) 3/19/94
\"
Dd June 28, 2025
Dt MAKE 1
Os
Sh NAME
Nm make
Nd maintain program dependencies
Sh SYNOPSIS
Nm
Op Fl BeikNnqrSstWwX
Op Fl C Ar directory
Op Fl D Ar variable
Op Fl d Ar flags
Op Fl f Ar makefile
Op Fl I Ar directory
Op Fl J Ar private
Op Fl j Ar max_jobs
Op Fl m Ar directory
Op Fl T Ar file
Op Fl V Ar variable
Op Fl v Ar variable
Op Ar variable\| Ns Cm \&= Ns Ar value
Op Ar target No ...
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
option is given,
Nm
looks for the makefiles listed in
Va .MAKE.MAKEFILE_PREFERENCE
(default
Sq Pa makefile ,
Sq Pa Makefile )
in order to find the specifications.
If the file
Sq 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"
(from 1993).
Pp
Nm
prepends the contents of the
Ev 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 making 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 scope.
It Fl d Oo Cm \- Oc Ns 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
Ev MAKEFLAGS
environment variable and are passed on to any child make processes.
By default, debugging information is printed to standard error,
but this can be changed using the
Cm F
debugging flag.
The debugging output is always unbuffered; in addition, if debugging
is enabled but debugging output is not directed to standard output,
the standard output is line buffered.
The available
Ar flags
are:
Bl -tag -width Ds
It Cm A
Print all possible debugging information;
equivalent to specifying all of the debugging flags.
It Cm a
Print debugging information about archive searching and caching.
It Cm C
Print debugging information about the current working directory.
It Cm c
Print debugging information about conditional evaluation.
It Cm d
Print debugging information about directory searching and caching.
It Cm e
Print debugging information about failed commands and targets.
It Cm F Ns Oo Cm \&+ 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
Cm F
flag is
Ql \&+ ,
the file is opened in append mode;
otherwise the file is overwritten.
If the file name is
Ql stdout
or
Ql stderr ,
debugging output is written to the standard output or standard error output
respectively (and the
Ql \&+
option has no effect).
Otherwise, the output is written to the named file.
If the file name ends with
Ql .%d ,
the
Ql %d
is replaced by the pid.
It Cm f
Print debugging information about loop evaluation.
It Cm g1
Print the input graph before making anything.
It Cm g2
Print the input graph after making everything, or before exiting
on error.
It Cm g3
Print the input graph before exiting on error.
It Cm h
Print debugging information about hash table operations.
It Cm j
Print debugging information about running multiple shells.
It Cm L
Turn on lint checks.
This throws errors for variable assignments that do not parse correctly,
at the time of assignment, so the file and line number are available.
It Cm l
Print commands in Makefiles regardless of whether or not they are prefixed by
Ql @
or other
Dq quiet
flags.
Also known as
Dq loud
behavior.
It Cm M
Print debugging information about
Dq meta
mode decisions about targets.
It Cm m
Print debugging information about making targets, including modification
dates.
It Cm 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 Cm p
Print debugging information about makefile parsing.
It Cm s
Print debugging information about suffix-transformation rules.
It Cm t
Print debugging information about target list maintenance.
It Cm V
Force the
Fl V
option to print raw values of variables,
overriding the default behavior set via
Va .MAKE.EXPAND_VARIABLES .
It Cm v
Print debugging information about variable assignment and expansion.
It Cm x
Run shell commands with
Fl x
so the actual commands are printed as they are executed.
El
It Fl e
Let environment variables override global variables within makefiles.
It Fl f Ar makefile
Specify a makefile to read instead of one of the defaults listed in
Va .MAKE.MAKEFILE_PREFERENCE .
If
Ar makefile
is
Ql \&- ,
standard input is read.
If
Ar makefile
starts with the string
Ql \&.../ ,
Nm
searches for the specified path in the rest of the argument
in the current directory and its parents.
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 \&-
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
Fl 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.
If
Ar max_jobs
is a floating point number, or ends with
Ql C ,
then the value is multiplied by the number of CPUs reported online by
Xr sysconf 3 .
The value of
Ar max_jobs
is saved in
Va .MAKE.JOBS .
Turns compatibility mode off, unless the
Fl B
option 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.
Pp
A job token pool with
Ar max_jobs
tokens is used to control the total number of jobs running.
Each instance of
Nm
will wait for a token from the pool before running a new job.
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
Pa sys.mk
and makefiles included via the
Li \&< Ns Ar file Ns Li \&> Ns -style
include statement.
The
Fl m
option can be used multiple times to form a search path.
This path overrides the default system include path
Pa /usr/share/mk .
Furthermore, the system include path is appended to the search path used for
Li \*q Ns Ar file Ns Li \*q Ns -style
include statements (see the
Fl I
option).
The system include path can be referenced via the read-only variable
Va .SYSPATH .
Pp
If a directory name in the
Fl m
argument (or the
Ev MAKESYSPATH
environment variable) starts with the string
Ql \&.../ ,
Nm
searches for the specified file or directory named in the remaining part
of the argument string.
The search starts with the current directory
and then works upward towards the root of the file system.
If the search is successful, the resulting directory replaces the
Ql \&.../
specification in the
Fl m
argument.
This feature allows
Nm
to easily search in the current source tree for customized
Pa sys.mk
files (e.g., by using
Ql \&.../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
Va .MAKE
special source (see below) or the command is prefixed with
Sq Cm + .
It Fl N
Display the commands that 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,
instead 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
Stop processing if an error is encountered.
This is the default behavior and the opposite of
Fl k .
It Fl s
Do not echo any commands as they are executed.
Equivalent to specifying
Sq 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 the value of
Ar variable .
Do not build any targets.
Multiple instances of this option may be specified;
the variables are printed one per line,
with a blank line for each null or undefined variable.
The value printed is extracted from the global scope after all
makefiles have been read.
Pp
By default, the raw variable contents (which may
include additional unexpanded variable references) are shown.
If
Ar variable
contains a
Ql \&$ ,
it is not interpreted as a variable name but rather as an expression.
Its value is expanded before printing.
The value is also expanded before printing if
Va .MAKE.EXPAND_VARIABLES
is set to true and the
Fl dV
option has not been used to override it.
Pp
Note that loop-local and target-local variables, as well as values
taken temporarily by global variables during makefile processing, are
not accessible via this option.
The
Fl dv
debug mode can be used to see these at the cost of generating
substantial extraneous output.
It Fl v Ar variable
Like
Fl V ,
but all printed variables are always expanded to their complete value.
The last occurrence of
Fl V
or
Fl v
decides whether all variables are expanded or not.
It Fl W
Treat any warnings during makefile parsing as errors.
It Fl w
Print entering and leaving directory messages, pre and post processing.
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
Ev MAKEFLAGS
environment variable.
This option may be useful on systems which have a small limit on the
size of command arguments.
It Ar variable\| Ns Cm \&= Ns Ar 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 several different types of lines in a makefile: dependency
specifications, shell commands, variable assignments, include statements,
conditional directives, for loops, other directives, and comments.
Pp
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 customarily created from them.
A target is considered out of date if it does not exist,
or if its modification time is less than that of any of its sources.
An out-of-date target is re-created, but not until all sources
have been examined and themselves re-created as needed.
Three operators may be used:
Bl -tag -width flag
It Ic \&:
Many dependency lines may name this target but only one may have
attached shell commands.
All sources named in all dependency lines are considered together,
and if needed the attached shell commands are run to create or
re-create the target.
If
Nm
is interrupted, the target is removed.
It Ic \&!
The same, but the target is always re-created whether or not it is out
of date.
It Ic \&::
Any dependency line may have attached shell commands, but each one
is handled independently: its sources are considered and the attached
shell commands are run if the target is out of date with respect to
(only) those sources.
Thus, different groups of the attached shell commands may be run
depending on the circumstances.
Furthermore, unlike
Ic \&: ,
for dependency lines with no sources, the attached shell
commands are always run.
Also unlike
Ic \&: ,
the target is not removed if
Nm
is interrupted.
El
Pp
All dependency lines mentioning a particular target must use the same
operator.
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 only match 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 one or more lines of shell commands,
normally used to create the target.
Each of the lines in this script
Em must
be preceded by a tab.
(For historical reasons, spaces are not accepted.)
While targets can occur in many dependency lines if desired,
by default only one of these rules may be followed by a creation script.
If the
Sq Ic \&::
operator is used, however, all rules may include scripts,
and the respective scripts are executed in the order found.
Pp
Each line is treated as a separate shell command,
unless the end of line is escaped with a backslash
Ql \e ,
in which case that line and the next are combined.
If the first characters of the command are any combination of
Sq Ic @ ,
Sq Ic + ,
or
Sq Ic \- ,
the command is treated specially.
Bl -tag -offset indent -width indent
It Ic @
causes the command not to be echoed before it is executed.
It Ic +
causes the command to be executed even when
Fl n
is given.
This is similar to the effect of the
Va .MAKE
special source,
except that the effect can be limited to a single line of a script.
It Ic \-
in compatibility mode
causes any non-zero exit status of the command line to be ignored.
El
Pp
When
Nm
is run in jobs mode with
Fl j Ar max_jobs ,
the entire script for the target is fed to a single instance of the shell.
In compatibility (non-jobs) mode, each command is run in a separate process.
If the command contains any shell meta characters
Pq Ql #=|^(){};&<>*?[]:$`\e\en ,
it is passed to the shell; otherwise
Nm
attempts direct execution.
If a line starts with
Sq Ic \-
and the shell has ErrCtl enabled,
failure of the command line is ignored as in compatibility mode.
Otherwise
Sq Ic \-
affects the entire job;
the script stops at the first command line that fails,
but the target is not deemed to have failed.
Pp
Makefiles should be written so that the mode of
Nm
operation does not change their behavior.
For example, any command which uses
Dq cd
or
Dq chdir
without the intention of changing the directory for subsequent commands
should be put in parentheses so it executes in a subshell.
To force the use of a single shell, escape the line breaks so as to make
the whole script one command.
For example:
Bd -literal -offset indent
avoid-chdir-side-effects:
       @echo "Building $@ in $$(pwd)"
       @(cd ${.CURDIR} && ${MAKE} $@)
       @echo "Back in $$(pwd)"

ensure-one-shell-regardless-of-mode:
       @echo "Building $@ in $$(pwd)"; \e
       (cd ${.CURDIR} && ${MAKE} $@); \e
       echo "Back in $$(pwd)"
Ed
Pp
Since
Nm
changes the current working directory to
Sq Va .OBJDIR
before executing any targets,
each child process starts with that as its current working directory.
Sh VARIABLE ASSIGNMENTS
Variables in make behave much like macros in the C preprocessor.
Pp
Variable assignments have the form
Sq Ar NAME Ar op Ar value ,
where:
Bl -tag -offset Ds -width Ds
It Ar NAME
is a single-word variable name,
consisting, by tradition, of all upper-case letters,
It Ar op
is one of the variable assignment operators described below, and
It Ar value
is interpreted according to the variable assignment operator.
El
Pp
Whitespace around
Ar NAME ,
Ar op
and
Ar value
is discarded.
Ss Variable assignment operators
The five operators that assign values to variables are:
Bl -tag -width Ds
It Ic \&=
Assign the value to the variable.
Any previous value is overwritten.
It Ic \&+=
Append the value to the current value of the variable,
separating them by a single space.
It Ic \&?=
Assign the value to the variable if it is not already defined.
It Ic \&:=
Expand the value, then assign it to the variable.
Pp
Em NOTE :
References to undefined variables are
Em not
expanded.
This can cause problems when variable modifiers are used.
\" See var-op-expand.mk, the section with LATER and INDIRECT.
It Ic \&!=
Expand the value and pass it to the shell for execution,
then assign the output from the child's standard output to the variable.
Any newlines in the result are replaced with spaces.
El
Ss Expansion of variables
In most contexts where variables are expanded,
Ql \&$$
expands to a single dollar sign.
In other contexts (most variable modifiers, string literals in conditions),
Ql \&\e$
expands to a single dollar sign.
Pp
References to variables have the form
Cm \&${ Ns Ar name Ns Oo Ns Cm \&: Ns Ar modifiers Oc Ns Cm \&}
or
Cm \&$( Ns Ar name Ns Oo Ns Cm \&: Ns Ar modifiers Oc Ns Cm \&) .
If the variable name consists of only a single character
and the expression contains no modifiers,
the surrounding curly braces or parentheses are not required.
This shorter form is not recommended.
Pp
If the variable name contains a dollar, the name itself is expanded first.
This allows almost arbitrary variable names, however names containing dollar,
braces, parentheses or whitespace are really best avoided.
Pp
If the result of expanding a nested variable expression contains a dollar sign
Pq Ql \&$ ,
the result is subject to further expansion.
Pp
Variable substitution occurs at four 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 conditionals are expanded individually,
but only as far as necessary to determine the result of the conditional.
It
Variables in shell commands are expanded when the shell command is
executed.
It
Ic .for
loop index variables are expanded on each loop iteration.
Note that other variables are not expanded when composing the body of a loop,
so the following example code:
Bd -literal -offset indent
\&.for i in 1 2 3
a+=     ${i}
j=      ${i}
b+=     ${j}
\&.endfor

all:
       @echo ${a}
       @echo ${b}
Ed
Pp
prints:
Bd -literal -offset indent
1 2 3
3 3 3
Ed
Pp
After the loop is executed:
Bl -tag -offset indent -width indent
It Va a
contains
Ql ${:U1} ${:U2} ${:U3} ,
which expands to
Ql 1 2 3 .
It Va j
contains
Ql ${:U3} ,
which expands to
Ql 3 .
It Va b
contains
Ql ${j} ${j} ${j} ,
which expands to
Ql ${:U3} ${:U3} ${:U3}
and further to
Ql 3 3 3 .
El
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.
El
Pp
Local variables can be set on a dependency line, unless
Va .MAKE.TARGET_LOCAL_VARIABLES
is set to
Ql false .
The rest of the line
(which already has had global variables expanded)
is the variable value.
For example:
Bd -literal -offset indent
COMPILER_WRAPPERS= ccache distcc icecc

${OBJS}: .MAKE.META.CMP_FILTER=${COMPILER_WRAPPERS:S,^,N,}
Ed
Pp
Only the targets
Ql ${OBJS}
are impacted by that filter (in
Dq meta
mode) and
simply enabling/disabling any of the compiler wrappers does not render all
of those targets out-of-date.
Pp
Em NOTE :
target-local variable assignments behave differently in that;
Bl -tag -width Ds -offset indent
It Ic \&+=
Only appends to a previous local assignment
for the same target and variable.
It Ic \&:=
Is redundant with respect to global variables,
which have already been expanded.
El
Pp
The built-in local variables are:
Bl -tag -width ".Va .ARCHIVE" -offset indent
It Va .ALLSRC
The list of all sources for this target; also known as
Sq Va \&>
or
Sq Va \&^ .
It Va .ARCHIVE
The name of the archive file; also known as
Sq Va \&! .
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
Sq Va \&< .
It is not defined in explicit rules.
It Va .MEMBER
The name of the archive member; also known as
Sq Va % .
It Va .OODATE
The list of sources for this target that were deemed out-of-date; also
known as
Sq Va \&? .
It Va .PREFIX
The name of the target with suffix (if declared in
Ic .SUFFIXES )
removed; also known as
Sq Va * .
It Va .TARGET
The name of the target; also known as
Sq Va @ .
For compatibility with other makes this is an alias for
Va .ARCHIVE
in archive member rules.
El
Pp
The shorter forms
Po
Sq Va \&> ,
Sq Va \&^ ,
Sq Va \&! ,
Sq Va \&< ,
Sq Va \&% ,
Sq Va \&? ,
Sq Va \&* ,
and
Sq Va \&@
Pc
are permitted for backward
compatibility with historical makefiles and legacy POSIX make and are
not recommended.
Pp
Variants of these variables with the punctuation followed immediately by
Ql D
or
Ql F ,
e.g.\&
Ql $(@D) ,
are legacy forms equivalent to using the
Ql :H
and
Ql :T
modifiers.
These forms are accepted for compatibility with
At V
makefiles and POSIX but 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
Sq Va .TARGET ,
Sq Va .PREFIX ,
Sq Va .ARCHIVE ,
and
Sq Va .MEMBER .
Ss Additional built-in variables
In addition,
Nm
sets or knows about the following variables:
Bl -tag
\" NB: This list is sorted case-insensitive, ignoring punctuation.
\" NB: To find all built-in variables in make's source code,
\" NB: search for Var_*, Global_*, SetVarObjdir, GetBooleanExpr,
\" NB: and the implementation of Var_SetWithFlags.
\" NB: Last synced on 2023-01-01.
It Va .ALLTARGETS
The list of all targets encountered in the makefiles.
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
Sq Va PWD
for more details.
It Va .ERROR_CMD
Is used in error handling, see
Va MAKE_PRINT_VAR_ON_ERROR .
It Va .ERROR_CWD
Is used in error handling, see
Va MAKE_PRINT_VAR_ON_ERROR .
It Va .ERROR_EXIT
Is used in error handling, see
Va MAKE_PRINT_VAR_ON_ERROR .
It Va .ERROR_META_FILE
Is used in error handling in
Dq meta
mode, see
Va MAKE_PRINT_VAR_ON_ERROR .
It Va .ERROR_TARGET
Is used in error handling, see
Va MAKE_PRINT_VAR_ON_ERROR .
It Va .INCLUDEDFROMDIR
The directory of the file this makefile was included from.
It Va .INCLUDEDFROMFILE
The filename of the file this makefile was included from.
\" .INCLUDES is intentionally undocumented, as it is obsolete.
\" .LIBS is intentionally undocumented, as it is obsolete.
It Va MACHINE
The machine hardware name, see
Xr uname 1 .
It Va MACHINE_ARCH
The machine processor architecture name, see
Xr uname 1 .
It Va MAKE
The name that
Nm
was executed with
Pq Va argv[0] .
It Va .MAKE
The same as
Va MAKE ,
for compatibility.
The preferred variable to use is the environment variable
Ev MAKE
because it is more compatible with other make variants
and cannot be confused with the special target with the same name.
\" '.MAKE.cmd_filtered' is intentionally undocumented,
\" as it is an internal implementation detail.
It Va .MAKE.DEPENDFILE
Names the makefile (default
Sq Pa .depend )
from which generated dependencies are read.
It Va .MAKE.DIE_QUIETLY
If set to
Ql true ,
do not print error information at the end.
It Va .MAKE.EXPAND_VARIABLES
A boolean that controls the default behavior of the
Fl V
option.
If true, variable values printed with
Fl V
are fully expanded; if false, the raw variable contents (which may
include additional unexpanded variable references) are shown.
It Va .MAKE.EXPORTED
The list of variables exported by
Nm .
It Va MAKEFILE
The top-level makefile that is currently read,
as given in the command line.
It Va .MAKEFLAGS
The environment variable
Sq 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
Va .MAKEFLAGS
variable, which is then added to the environment for all programs that
Nm
executes.
It Va .MAKE.GID
The numeric group ID of the user running
Nm .
It is read-only.
It Va .MAKE.JOB.PREFIX
If
Nm
is run with
Fl j ,
the output for each target is prefixed with a token
Dl --- Ar target Li ---
the first part of which can be controlled via
Va .MAKE.JOB.PREFIX .
If
Va .MAKE.JOB.PREFIX
is empty, no token is printed.
For example, setting
Va .MAKE.JOB.PREFIX
to
Ql ${.newline}---${.MAKE:T}[${.MAKE.PID}]
would produce tokens like
Dl ---make[1234] Ar target Li ---
making it easier to track the degree of parallelism being achieved.
It Va .MAKE.JOBS
The argument to the
Fl j
option.
It Va .MAKE.JOBS.C
A read-only boolean that indicates whether the
Fl j
option supports use of
Ql C .
It Va .MAKE.LEVEL
The recursion depth of
Nm .
The top-level instance of
Nm
has level 0, and each child make has its parent level plus 1.
This allows tests like:
Li .if ${.MAKE.LEVEL} == 0
to protect things which should only be evaluated in the top-level instance of
Nm .
It Va .MAKE.LEVEL.ENV
The name of the environment variable that stores the level of nested calls to
Nm .
It Va .MAKE.MAKEFILE_PREFERENCE
The ordered list of makefile names
(default
Sq Pa makefile ,
Sq Pa Makefile )
that
Nm
looks 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.META.BAILIWICK
In
Dq 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.CMP_FILTER
In
Dq meta
mode, it can (very rarely!) be useful to filter command
lines before comparison.
This variable can be set to a set of modifiers that are applied to
each line of the old and new command that differ, if the filtered
commands still differ, the target is considered out-of-date.
It Va .MAKE.META.CREATED
In
Dq 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
Dq 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.IGNORE_FILTER
Provides a list of variable modifiers to apply to each pathname.
Ignore if the expansion is an empty string.
It Va .MAKE.META.IGNORE_PATHS
Provides a list of path prefixes that should be ignored;
because the contents are expected to change over time.
The default list includes:
Sq Pa /dev /etc /proc /tmp /var/run /var/tmp
It Va .MAKE.META.IGNORE_PATTERNS
Provides a list of patterns to match against pathnames.
Ignore any that match.
It Va .MAKE.META.PREFIX
Defines the message printed for each meta file updated in
Dq meta verbose
mode.
The default value is:
Dl Building ${.TARGET:H:tA}/${.TARGET:T}
It Va .MAKE.MODE
Processed after reading all makefiles.
Affects the mode that
Nm
runs in.
It can contain these keywords:
Bl -tag -width indent
It Cm compat
Like
Fl B ,
puts
Nm
into
Dq compat
mode.
It Cm meta
Puts
Nm
into
Dq meta
mode, where meta files are created for each target
to capture the commands 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 useful when diagnosing errors.
Pp
Nm
will use the information in the meta file to help determine if
a target is out-of-date when the normal dependency rules
indicate it is not.
Pp
First,
the commands to be executed,
will be compared to those captured previously,
if any differ,
the target is out-of-date.
Pp
This allows for a huge improvement in the reliability
and efficiency of update builds.
It is no longer necessary for targets to depend on makefiles
just in-case they set a variable that might be relevant.
Mechanisms such as
Va .MAKE.META.CMP_FILTER
and
Ic .NOMETA_CMP ,
allow limiting or disabling that comparison on a per target basis.
A reference to the variable
Va .OODATE
can be leveraged to block comparison of certain commands.
For example:
Ql ${.OODATE:M}
will expand to nothing and have no impact on the target,
its side-effect though,
will be to prevent comparison of any command line it appears on.
For documentation purposes
Ql ${.OODATE:MNOMETA_CMP}
is useful.
Pp
If necessary,
Nm
will then use the information captured by
Xr filemon 4 ,
to check the modification time of any file used in generating
the target,
if any is newer,
the target is out-of-date.
Pp
Such deep inspection can easily lead to cases where a target is
Em always
considered out-of-date, which is why
Va .MAKE.META.IGNORE_FILTER ,
Va .MAKE.META.IGNORE_PATHS
and
Va .MAKE.META.IGNORE_PATTERNS ,
are provided to limit that inspection when necessary.
It Cm curdirOk= Ns Ar bf
By default,
Nm
does not create
Pa .meta
files in
Sq Va .CURDIR .
This can be overridden by setting
Ar bf
to a value which represents true.
It Cm missing-meta= Ns Ar bf
If
Ar bf
is true, a missing
Pa .meta
file makes the target out-of-date.
It Cm missing-filemon= Ns Ar bf
If
Ar bf
is true, missing filemon data makes the target out-of-date.
It Cm nofilemon
Do not use
Xr filemon 4 .
It Cm env
For debugging, it can be useful to include the environment
in the
Pa .meta
file.
It Cm verbose
If in
Dq meta
mode, print a clue about the target being built.
This is useful if the build is otherwise running silently.
The message printed is the expanded value of
Va .MAKE.META.PREFIX .
It Cm 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
Dq meta
mode.
See also
Ic .NOMETA_CMP .
It Cm silent= Ns Ar bf
If
Ar bf
is true, when a .meta file is created, mark the target
Ic .SILENT .
It Cm randomize-targets
In both compat and parallel mode, do not make the targets in the usual order,
but instead randomize their order.
This mode can be used to detect undeclared dependencies between files.
El
It Va MAKEOBJDIR
Used to create files in a separate directory, see
Va .OBJDIR .
It Va MAKE_OBJDIR_CHECK_WRITABLE
When true,
Nm
will check that
Va .OBJDIR
is writable, and issue a warning if not.
It Va MAKE_DEBUG_OBJDIR_CHECK_WRITABLE
When true and
Nm
is warning about an unwritable
Va .OBJDIR ,
report the variables listed in
Va MAKE_PRINT_VAR_ON_ERROR
to help debug.
It Va MAKEOBJDIRPREFIX
Used to create files in a separate directory, see
Va .OBJDIR .
It should be an absolute path.
It Va .MAKE.OS
The name of the operating system, see
Xr uname 1 .
It is read-only.
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
Sq Ev MAKEFLAGS .
This behavior can be disabled by assigning an empty value to
Sq Va .MAKEOVERRIDES
within a makefile.
Extra variables can be exported from a makefile
by appending their names to
Sq Va .MAKEOVERRIDES .
Sq Ev MAKEFLAGS
is re-exported whenever
Sq Va .MAKEOVERRIDES
is modified.
It Va .MAKE.PATH_FILEMON
If
Nm
was built with
Xr filemon 4
support, this is set to the path of the device node.
This allows makefiles to test for this support.
It Va .MAKE.PID
The process ID of
Nm .
It is read-only.
It Va .MAKE.PPID
The parent process ID of
Nm .
It is read-only.
It Va MAKE_PRINT_VAR_ON_ERROR
When
Nm
stops due to an error, it sets
Sq Va .ERROR_TARGET
to the name of the target that failed,
Sq Va .ERROR_EXIT
to the exit status of the failed target,
Sq Va .ERROR_CMD
to the commands of the failed target,
and in
Dq meta
mode, it also sets
Sq Va .ERROR_CWD
to the
Xr getcwd 3 ,
and
Sq Va .ERROR_META_FILE
to the path of the meta file (if any) describing the failed target.
It then prints its name and the value of
Sq Va .CURDIR
as well as the value of any variables named in
Sq Va MAKE_PRINT_VAR_ON_ERROR .
It Va .MAKE.SAVE_DOLLARS
If true,
Ql $$
are preserved when doing
Ql :=
assignments.
The default is true, for compatibility with other makes.
If set to false,
Ql $$
becomes
Ql $
per normal evaluation rules.
It Va .MAKE.TARGET_LOCAL_VARIABLES
If set to
Ql false ,
apparent variable assignments in dependency lines are
treated as normal sources.
It Va .MAKE.UID
The numeric ID of the user running
Nm .
It is read-only.
\" 'MAKE_VERSION' is intentionally undocumented
\" since it is only defined in the bmake distribution,
\" but not in NetBSD's native make.
\" '.meta.%d.lcwd' is intentionally undocumented
\" since it is an internal implementation detail.
\" '.meta.%d.ldir' is intentionally undocumented
\" since it is an internal implementation detail.
\" 'MFLAGS' is intentionally undocumented
\" since it is obsolete.
It Va .newline
This variable is simply assigned a newline character as its value.
It is read-only.
This allows expansions using the
Cm \&:@
modifier to put a newline between
iterations of the loop rather than a space.
For example, in case of an error,
Nm
prints the variable names and their values using:
Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$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
Cm ${MAKEOBJDIRPREFIX} Ns Cm ${.CURDIR}
Pp
(Only if
Sq Ev MAKEOBJDIRPREFIX
is set in the environment or on the command line.)
It
Cm ${MAKEOBJDIR}
Pp
(Only if
Sq Ev MAKEOBJDIR
is set in the environment or on the command line.)
It
Cm ${.CURDIR} Ns Pa /obj. Ns Cm ${MACHINE}
It
Cm ${.CURDIR} Ns Pa /obj
It
Pa /usr/obj/ Ns Cm ${.CURDIR}
It
Cm ${.CURDIR}
El
Pp
Variable expansion is performed on the value before it is used,
so expressions such as
Cm ${.CURDIR:S,^/usr/src,/var/obj,}
may be used.
This is especially useful with
Sq Ev MAKEOBJDIR .
Pp
Sq Va .OBJDIR
may be modified in the makefile via the special target
Sq Ic .OBJDIR .
In all cases,
Nm
changes to the specified directory if it exists, and sets
Sq Va .OBJDIR
and
Sq Va PWD
to that directory before executing any targets.
Pp
Except in the case of an explicit
Sq Ic .OBJDIR
target,
Nm
checks that the specified directory is writable and ignores it if not.
This check can be skipped by setting the environment variable
Sq Ev MAKE_OBJDIR_CHECK_WRITABLE
to
Dq no .
It Va .PARSEDIR
The directory name of the current makefile being parsed.
It Va .PARSEFILE
The basename of the current makefile being parsed.
This variable and
Sq Va .PARSEDIR
are both set only while the makefiles are being parsed.
To retain their current values,
assign them to a variable using assignment with expansion
Sq Cm \&:= .
It Va .PATH
The space-separated list of directories that
Nm
searches for files.
To update this search list, use the special target
Sq Ic .PATH
rather than modifying the variable directly.
It Va %POSIX
Is set in POSIX mode, see the special
Ql Va .POSIX
target.
\" XXX: There is no make variable named 'PWD',
\" XXX: make only reads and writes the environment variable 'PWD'.
It Va PWD
Alternate path to the current directory.
Nm
normally sets
Sq Va .CURDIR
to the canonical path given by
Xr getcwd 3 .
However, if the environment variable
Sq Ev PWD
is set and gives a path to the current directory,
Nm
sets
Sq Va .CURDIR
to the value of
Sq Ev PWD
instead.
This behavior is disabled if
Sq Ev MAKEOBJDIRPREFIX
is set or
Sq Ev MAKEOBJDIR
contains a variable transform.
Sq Va PWD
is set to the value of
Sq Va .OBJDIR
for all programs which
Nm
executes.
It Va .SHELL
The pathname of the shell used to run target scripts.
It is read-only.
It Va .SUFFIXES
The list of known suffixes.
It is read-only.
It Va .SYSPATH
The space-separated list of directories that
Nm
searches for makefiles, referred to as the system include path.
To update this search list, use the special target
Sq Ic .SYSPATH
rather than modifying the variable which is read-only.
It Va .TARGETS
The list of targets explicitly specified on the command line, if any.
It Va VPATH
The colon-separated
Pq Dq \&:
list of directories that
Nm
searches for files.
This variable is supported for compatibility with old make programs only, use
Sq Va .PATH
instead.
El
Ss Variable modifiers
The general format of a variable expansion is:
Pp
Sm off
D1 Ic \&${ Ar variable\| Oo Ic \&: Ar modifier\| Oo Ic \&: No ... Oc Oc Ic \&}
Sm on
Pp
Each modifier begins with a colon.
To escape a colon, precede it with a backslash
Ql \e .
Pp
A list of indirect modifiers can be specified via a variable, as follows:
Pp
Bd -literal -offset indent
Ar modifier_variable\^ Li \&= Ar modifier Ns Oo Ic \&: Ns No ... Oc

Sm off
Ic \&${ Ar variable Ic \&:${ Ar modifier_variable Ic \&} Oo Ic \&: No ... Oc Ic \&}
Sm on
Ed
Pp
In this case, the first modifier in the
Ar modifier_variable
does not start with a colon,
since that colon already occurs in the referencing variable.
If any of the modifiers in the
Ar modifier_variable
contains a dollar sign
Pq Ql $ ,
these must be doubled to avoid early expansion.
Pp
Some modifiers interpret the expression value as a single string,
others treat the expression value as a whitespace-separated list of words.
When splitting a string into words,
whitespace can be escaped using double quotes, single quotes and backslashes,
like in the shell.
The quotes and backslashes are retained in the words.
Pp
The supported modifiers are:
Bl -tag -width EEE
It Cm \&:E
Replaces each word with its suffix.
It Cm \&:H
Replaces each word with its dirname.
It Cm \&:M\| Ns Ar pattern
Selects only those words that match
Ar pattern .
The standard shell wildcard characters
Pf ( Ql * ,
Ql \&? ,
and
Ql \&[] )
may
be used.
The wildcard characters may be escaped with a backslash
Pq Ql \e .
As a consequence of the way values are split into words, matched,
and then joined, the construct
Ql ${VAR:M*}
removes all leading and trailing whitespace
and normalizes the inter-word spacing to a single space.
It Cm \&:N\| Ns Ar pattern
This is the opposite of
Sq Cm \&:M ,
selecting all words which do
Em not
match
Ar pattern .
It Cm \&:O
Orders the words lexicographically.
It Cm \&:On
Orders the words numerically.
A number followed by one of
Ql k ,
Ql M
or
Ql G
is multiplied by the appropriate factor, which is 1024 for
Ql k ,
1048576 for
Ql M ,
or 1073741824 for
Ql G .
Both upper- and lower-case letters are accepted.
It Cm \&:Or
Orders the words in reverse lexicographical order.
It Cm \&:Orn
Orders the words in reverse numerical order.
It Cm \&:Ox
Shuffles the words.
The results are different each time you are referring to the
modified variable; use the assignment with expansion
Sq Cm \&:=
to prevent such behavior.
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 value, so that it can be passed
safely to the shell.
It Cm \&:q
Quotes every shell meta-character in the value, and also doubles
Sq $
characters so that it can be passed
safely through recursive invocations of
Nm .
This is equivalent to
Sq Cm \&:S/\e\&$/&&/g:Q .
It Cm \&:R
Replaces each word with everything but its suffix.
It Cm \&:range Ns Oo Cm = Ns Ar count Oc
The value is an integer sequence representing the words of the original
value, or the supplied
Ar count .
It Cm \&:gmtime Ns Oo Cm = Ns Ar timestamp Oc
The value is interpreted as a format string for
Xr strftime 3 ,
using
Xr gmtime 3 ,
producing the formatted timestamp.
Note: the
Ql %s
format should only be used with
Sq Cm \&:localtime .
If a
Ar timestamp
value is not provided or is 0, the current time is used.
It Cm \&:hash
Computes a 32-bit hash of the value and encodes it as 8 hex digits.
It Cm \&:localtime Ns Oo Cm = Ns Ar timestamp Oc
The value is interpreted as a format string for
Xr strftime 3 ,
using
Xr localtime 3 ,
producing the formatted timestamp.
If a
Ar timestamp
value is not provided or is 0, the current time is used.
It Cm \&:mtime Ns Oo Cm = Ns Ar timestamp Oc
Call
Xr stat 2
with each word as pathname;
use
Ql st_mtime
as the new value.
If
Xr stat 2
fails; use
Ar timestamp
or current time.
If
Ar timestamp
is set to
Ql error ,
then
Xr stat 2
failure will cause an error.
It Cm \&:tA
Attempts to convert the value to an absolute path using
Xr realpath 3 .
If that fails, the value is unchanged.
It Cm \&:tl
Converts the value to lower-case letters.
It Cm \&:ts Ns Ar c
When joining the words after a modifier that treats the value as words,
the words are normally separated by a space.
This modifier changes the separator to the character
Ar c .
If
Ar c
is omitted, no separator is used.
The common escapes (including octal numeric codes) work as expected.
It Cm \&:tt
Converts the first character of each word to upper-case,
and the rest to lower-case letters.
It Cm \&:tu
Converts the value to upper-case letters.
It Cm \&:tW
Causes subsequent modifiers to treat the value as a single word
(possibly containing embedded whitespace).
See also
Sq Cm \&:[*] .
It Cm \&:tw
Causes the value to be treated as a list of words.
See also
Sq Cm \&:[@] .
Sm off
It Cm \&:S\| No \&/ Ar old_string\| No \&/ Ar new_string\| No \&/ Op Cm 1gW
Sm on
Modifies the first occurrence of
Ar old_string
in each word of the value, replacing it with
Ar new_string .
If a
Ql g
is appended to the last delimiter of the pattern,
all occurrences in each word are replaced.
If a
Ql 1
is appended to the last delimiter of the pattern,
only the first occurrence is affected.
If a
Ql W
is appended to the last delimiter of the pattern,
the value is treated as a single word.
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 &
is replaced by
Ar old_string
(without the anchoring
Ql ^
or
Ql \&$ ) .
Any character may be used as the delimiter for the parts of the modifier
string.
The anchoring, ampersand and delimiter characters can be escaped with a
backslash
Pq Ql \e .
Pp
Both
Ar old_string
and
Ar new_string
may contain nested expressions.
To prevent a dollar sign from starting a nested expression,
escape it with a backslash.
Sm off
It Cm \&:C\| No \&/ Ar pattern\| No \&/ Ar replacement\| No \&/ Op Cm 1gW
Sm on
The
Cm \&:C
modifier works like the
Cm \&:S
modifier except that the old and new strings, instead of being
simple strings, are an extended regular expression
Ar pattern
(see
Xr regex 3 )
and an
Xr ed 1 Ns \-style
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 whitespace).
Pp
As for the
Cm \&:S
modifier, the
Ar pattern
and
Ar replacement
are subjected to variable expansion before being parsed as
regular expressions.
It Cm \&:T
Replaces each word with its last path component (basename).
It Cm \&:u
Removes 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
Cm .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
No itself Ns \^\(em\^ Ns
which, of course, usually contains variable expansions.
A common error is trying to use expressions like
Dl ${NUMBERS:M42:?match:no}
which actually tests defined(NUMBERS).
To determine if any words match
Dq 42 ,
you need to use something like:
Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
It Cm :\| Ns Ar old_string\| Ns Cm = Ns Ar new_string
This is the
At V
style substitution.
It can only be the last modifier specified,
as a
Ql \&:
in either
Ar old_string
or
Ar new_string
is treated as a regular character, not as the end of the modifier.
Pp
If
Ar old_string
does not contain the pattern matching character
Ql % ,
and the word ends with
Ar old_string
or equals it,
that suffix is replaced with
Ar new_string .
Pp
Otherwise, the first
Ql %
in
Ar old_string
matches a possibly empty substring of arbitrary characters,
and if the whole pattern is found in the word,
the matching part is replaced with
Ar new_string ,
and the first occurrence of
Ql %
in
Ar new_string
(if any) is replaced with the substring matched by the
Ql % .
Pp
Both
Ar old_string
and
Ar new_string
may contain nested expressions.
To prevent a dollar sign from starting a nested expression,
escape it with a backslash.
Sm off
It Cm \&:@ Ar varname\| 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.
For each word in the value, assign the word to the variable named
Ar varname
and evaluate
Ar string .
The ODE convention is that
Ar varname
should start and end with a period, for example:
Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
Pp
However, a single-letter variable is often more readable:
Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
It Cm \&:_ Ns Oo Cm = Ns Ar var Oc
Saves the current variable value in
Ql $_
or the named
Ar var
for later reference.
Example usage:
Bd -literal -offset indent
M_cmpv.units = 1 1000 1000000
M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\
\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh

Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}

Ed
Here
Ql $_
is used to save the result of the
Ql :S
modifier which is later referenced using the index values from
Ql :range .
It Cm \&:U\| Ns Ar newval
If the variable is undefined,
the optional
Ar newval
(which may be empty) 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
(which may be empty) 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, the name of the variable is used.
In order for this modifier to work, the name (node) must at least have
appeared on the right-hand side of a dependency.
Sm off
It Cm \&:\&! Ar cmd\| Cm \&!
Sm on
The output of running
Ar cmd
is the value.
It Cm \&:sh
The value 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
at a point where a target's shell commands are being parsed.
These assignment modifiers always expand to nothing.
Pp
The
Sq Cm \&::
helps avoid false matches with the
At V
style
Ql \&:=
modifier and since substitution always occurs, the
Ql \&::=
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 split into words.
Pp
An empty value, or a value that consists entirely of white-space,
is treated as a single word.
For the purposes of the
Sq 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,
Sq Cm \&:[2..-1]
selects all words from the second word to the last word.
If
Ar start
is greater than
Ar end ,
the words are output in reverse order.
For example,
Sq Cm \&:[-1..1]
selects all the words from last to first.
If the list is already ordered,
this effectively reverses the list,
but it is more efficient to use
Sq Cm \&:Or
instead of
Sq Cm \&:O:[-1..1] .
\" :[*]
It Cm \&*
Causes subsequent modifiers to treat the value as a single word
(possibly containing embedded whitespace).
Analogous to the effect of
Li \&$*
in Bourne shell.
\" :[0]
It 0
Means the same as
Sq Cm \&:[*] .
\" :[*]
It Cm \&@
Causes subsequent modifiers to treat the value as a sequence of words
delimited by whitespace.
Analogous to the effect of
Li \&$@
in Bourne shell.
\" :[#]
It Cm \&#
Returns the number of words in the value.
El \" :[range]
El
Sh DIRECTIVES
Nm
offers directives for including makefiles, conditionals and for loops.
All these directives are identified by a line beginning with a single dot
Pq Ql \&.
character, followed by the keyword of the directive, such as
Cm include
or
Cm if .
Ss File inclusion
Files are included with either
Cm \&.include \&< Ns Ar file Ns Cm \&>
or
Cm \&.include \&\*q Ns Ar file Ns Cm \&\*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.
Pp
For compatibility with other make variants,
Sq Cm include Ar file No ...
(without leading dot)
is also accepted.
Pp
If the include statement is written as
Cm .-include
or as
Cm .sinclude ,
errors locating and/or opening include files are ignored.
Pp
If the include statement is written as
Cm .dinclude ,
not only are errors locating and/or opening include files ignored,
but stale dependencies within the included file are ignored just like in
Va .MAKE.DEPENDFILE .
Ss Exporting variables
The directives for exporting and unexporting variables are:
Bl -tag -width Ds
It Ic .export Ar variable No ...
Export the specified global variable.
Pp
For compatibility with other make programs,
Cm export Ar variable\| Ns Cm \&= Ns Ar value
(without leading dot) is also accepted.
Pp
Appending a variable name to
Va .MAKE.EXPORTED
is equivalent to exporting a variable.
It Ic .export-all
Export all globals except for internal variables (those that start with
Ql \&. ) .
This is not affected by the
Fl X
flag, so should be used with caution.
It Ic .export-env Ar variable No ...
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 .export-literal Ar variable No ...
The same as
Ql .export-env ,
except that variables in the value are not expanded.
It Ic .unexport Ar variable No ...
The opposite of
Ql .export .
The specified global
Ar variable
is 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 causes 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
Sq Ev PATH ,
which is the minimal useful environment.
\" TODO: Check the below sentence, environment variables don't start with '.'.
Actually
Sq Va .MAKE.LEVEL
is also pushed into the new environment.
El
Ss Messages
The directives for printing messages to the output are:
Bl -tag -width Ds
It Ic .info Ar message
The message is printed along with the name of the makefile and line number.
It Ic .warning Ar message
The message prefixed by
Sq Li warning:
is printed along with the name of the makefile and line number.
It Ic .error Ar message
The message is printed along with the name of the makefile and line number,
Nm
exits immediately.
El
Ss Conditionals
The directives for conditionals are:
ds maybenot Oo Ic \&! Oc Ns
Bl -tag
It Ic .if \*[maybenot] Ar expression Op Ar operator expression No ...
Test the value of an expression.
It Ic .ifdef \*[maybenot] Ar variable Op Ar operator variable No ...
Test whether a variable is defined.
It Ic .ifndef \*[maybenot] Ar variable Op Ar operator variable No ...
Test whether a variable is not defined.
It Ic .ifmake \*[maybenot] Ar target Op Ar operator target No ...
Test the target being requested.
It Ic .ifnmake \*[maybenot] Ar target Op Ar operator target No ...
Test the target being requested.
It Ic .else
Reverse the sense of the last conditional.
It Ic .elif \*[maybenot] Ar expression Op Ar operator expression No ...
A combination of
Sq Ic .else
followed by
Sq Ic .if .
It Ic .elifdef \*[maybenot] Ar variable Op Ar operator variable No ...
A combination of
Sq Ic .else
followed by
Sq Ic .ifdef .
It Ic .elifndef \*[maybenot] Ar variable Op Ar operator variable No ...
A combination of
Sq Ic .else
followed by
Sq Ic .ifndef .
It Ic .elifmake \*[maybenot] Ar target Op Ar operator target No ...
A combination of
Sq Ic .else
followed by
Sq Ic .ifmake .
It Ic .elifnmake \*[maybenot] Ar target Op Ar operator target No ...
A combination of
Sq Ic .else
followed by
Sq 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
It Ic \&|\&|
Logical OR.
It Ic \&&&
Logical AND; of higher precedence than
Sq Ic \&|\&| .
El
Pp
Nm
only evaluates a conditional as far as is necessary to determine its value.
Parentheses can be used to override the operator precedence.
The boolean operator
Sq Ic \&!
may be used to logically negate an expression, typically a function call.
It is of higher precedence than
Sq Ic \&&& .
Pp
The value of
Ar expression
may be any of the following function call expressions:
Bl -tag
Sm off
It Ic defined Li \&( Ar varname Li \&)
Sm on
Evaluates to true if the variable
Ar varname
has been defined.
Sm off
It Ic make Li \&( Ar target Li \&)
Sm on
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.
Sm off
It Ic empty Li \&( Ar varname Oo Li : Ar modifiers Oc Li \&)
Sm on
Evaluates to true if the expansion of the variable,
after applying the modifiers, results in an empty string.
Sm off
It Ic exists Li \&( Ar pathname Li \&)
Sm on
Evaluates to true if the given pathname exists.
If relative, the pathname is searched for on the system search path (see
Va .PATH ) .
Sm off
It Ic target Li \&( Ar target Li \&)
Sm on
Evaluates to true if the target has been defined.
Sm off
It Ic commands Li \&( Ar target Li \&)
Sm on
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.
If both sides are numeric and neither is enclosed in quotes,
the comparison is done numerically, otherwise lexicographically.
A string is interpreted as a hexadecimal integer if it is preceded by
Li 0x ,
otherwise it is interpreted as a decimal floating-point number;
octal numbers are not supported.
Pp
All comparisons may use the operators
Sq Ic \&==
and
Sq Ic \&!= .
Numeric comparisons may also use the operators
Sq Ic \&< ,
Sq Ic \&<= ,
Sq Ic \&>
and
Sq Ic \&>= .
Pp
If the comparison has neither a comparison operator nor a right side,
the expression evaluates to true if it is nonempty
and its numeric value (if any) is not zero.
Pp
When
Nm
is evaluating one of these conditional expressions, and it encounters
a (whitespace-separated) word it doesn't recognize, either the
Dq make
or
Dq defined
function is applied to it, depending on the form of the conditional.
If the form is
Sq Ic .ifdef ,
Sq Ic .ifndef
or
Sq Ic .if ,
the
Dq defined
function is applied.
Similarly, if the form is
Sq Ic .ifmake
or
Sq Ic .ifnmake ,
the
Dq make
function is applied.
Pp
If the conditional evaluates to true,
parsing of the makefile continues as before.
If it evaluates to false, the following lines until the corresponding
Sq Ic .elif
variant,
Sq Ic .else
or
Sq Ic .endif
are skipped.
Ss For loops
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 No ... Oc Ic in Ar expression
It Aq Ar make-lines
It Ic \&.endfor
El
Pp
The
Ar expression
is expanded and then split into words.
On each iteration of the loop, one word is taken and assigned to each
Ar variable ,
in order, and these
Ar variables
are substituted into the
Ar make-lines
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.
Pp
If
Sq Ic .break
is encountered within a
Cm \&.for
loop, it causes early termination of the loop, otherwise a parse error.
\" TODO: Describe limitations with defined/empty.
Ss Other directives
Bl -tag -width Ds
It Ic .undef Ar variable No ...
Un-define the specified global variables.
Only global variables can be un-defined.
El
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
Dq 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 is still considered out of date.
The same effect applies to any command line that uses the variable
Va .OODATE ,
which can be used for that purpose even when not otherwise needed or desired:
Bd -literal -offset indent

skip-compare-for-some:
       @echo this is compared
       @echo this is not ${.OODATE:M.NOMETA_CMP}
       @echo this is also compared

Ed
The
Cm \&:M
pattern suppresses any expansion of the unwanted variable.
It Ic .NOPATH
Do not search for the target in the directories specified by
Va .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 ignores this fact and assumes
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 is not 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
Like
Ic .USE ,
but instead of appending, 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 .
Pp
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
Va .IMPSRC
variable of a target that inherits
Ic .DEFAULT Ns 's
commands is set to the target's own name.
It Ic .DELETE_ON_ERROR
If this target is present in the makefile, it globally causes make to
delete targets whose commands fail.
(By default, only targets whose commands are interrupted during
execution are deleted.
This is the historical behavior.)
This setting can be used to help prevent half-finished or malformed
targets from being left around and corrupting future rebuilds.
It Ic .END
Any command lines attached to this target are executed after everything
else is done successfully.
It Ic .ERROR
Any command lines attached to this target are executed when another target fails.
See
Va MAKE_PRINT_VAR_ON_ERROR
for the variables that will be set.
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 are executed.
It Ic .MAIN
If no target is specified when
Nm
is invoked, this target is built.
It Ic .MAKEFLAGS
This target provides a way to specify flags for
Nm
at the time when the makefiles are read.
The flags are as if typed to the shell, though the
Fl f
option has
no effect.
\" XXX: NOT YET!!!!
\" .It Ic .NOTPARALLEL
\" The named targets are executed in non parallel mode.
\" If no targets are
\" specified, 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 .NOREADONLY
clear the read-only attribute from the global variables specified as sources.
It Ic .OBJDIR
The source is a new value for
Sq Va .OBJDIR .
If it exists,
Nm
changes the current working directory to it and updates the value of
Sq Va .OBJDIR .
It Ic .ORDER
In parallel mode, the named targets are made in sequence.
This ordering does not add targets to the list of targets to be made.
Pp
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
\" XXX: NOT YET!!!!
\" .It Ic .PARALLEL
\" The named targets are executed in parallel mode.
\" If no targets are
\" specified, 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 removed from the search path.
If the source is the special
Ic .DOTLAST
target, the current working directory is searched last.
It Ic .PATH. Ns Ar suffix
Like
Ic .PATH
but applies only to files with a particular suffix.
The suffix must have been previously declared with
Ic .SUFFIXES .
It Ic .PHONY
Apply the
Ic .PHONY
attribute to any specified sources.
It Ic .POSIX
If this is the first non-comment line in the main makefile,
the variable
Va %POSIX
is set to the value
Ql 1003.2
and the makefile
Ql <posix.mk>
is included if it exists,
to provide POSIX-compatible default rules.
If
Nm
is run with the
Fl r
flag, only
Ql posix.mk
contributes to the default rules.
In POSIX-compatible mode, the AT&T System V UNIX style substitution
modifier is checked first rather than as a fallback.
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 .READONLY
set the read-only attribute on the global variables specified as sources.
It Ic .SHELL
Sets the shell that
Nm
uses to execute commands.
The sources are a set of
Ar field\| Ns Cm \&= Ns Ar value
pairs.
Bl -tag -width ".Li hasErrCtls"
It Li name
This is the minimal specification, used to select one of the built-in
shell specs;
Li sh ,
Li ksh ,
and
Li csh .
It Li path
Specifies the absolute path to the shell.
It Li hasErrCtl
Indicates whether the shell supports exit on error.
It Li check
The command to turn on error checking.
It Li ignore
The command to disable error checking.
It Li echo
The command to turn on echoing of commands executed.
It Li quiet
The command to turn off echoing of commands executed.
It Li filter
The output to filter after issuing the
Li quiet
command.
It is typically identical to
Li quiet .
It Li errFlag
The flag to pass the shell to enable error checking.
It Li echoFlag
The flag to pass the shell to enable command echoing.
It Li 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 .STALE
This target gets run when a dependency file contains stale entries, having
Va .ALLSRC
set to the name of that dependency 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: .c .o
\&.c.o:
       cc \-o ${.TARGET} \-c ${.IMPSRC}
Ed
It Ic .SYSPATH
The sources are directories which are to be added to the system
include path which
Nm
searches for makefiles.
If no sources are specified,
any previously specified directories are removed from the system
include path.
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 MAKE_STACK_TRACE ,
Ev PWD ,
and
Ev TMPDIR .
Pp
Ev MAKEOBJDIRPREFIX
and
Ev MAKEOBJDIR
should be set in the environment or on the command line to
Nm
and not as makefile variables;
see the description of
Sq Va .OBJDIR
for more details.
It is possible to set these via makefile variables but unless done
very early and the
Sq Ic .OBJDIR
target is used to reset
Sq Va .OBJDIR ,
there may be unexpected side effects.
Pp
If the
Ev MAKE_STACK_TRACE
environment variable is set to
Dq yes ,
any stack traces include the call chain of the parent processes.
Sh FILES
Bl -tag -width /usr/share/mk -compact
It .depend
list of dependencies
It makefile
first default makefile if no makefile is specified on the command line
It Makefile
second default makefile if no makefile is specified on the command line
It sys.mk
system makefile
It /usr/share/mk
system makefile directory
El
Sh COMPATIBILITY
The basic make syntax is compatible between different make variants;
however the special variables, variable modifiers and conditionals are not.
Ss Older versions
An incomplete list of changes in older versions of
Nm :
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
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.
Ss Other make dialects
Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
support most of the features of
Nm
as described in this manual.
Most notably:
Bl -bullet -offset indent
It
The
Ic .WAIT
and
Ic .ORDER
declarations and most functionality pertaining to parallelization.
(GNU make supports parallelization but lacks the features needed to
control it effectively.)
It
Directives, including for loops and conditionals and most of the
forms of include files.
(GNU make has its own incompatible and less powerful syntax for
conditionals.)
\" The "less powerful" above means that GNU make does not have the
\" make(target), target(target) and commands(target) functions.
It
All built-in variables that begin with a dot.
It
Most of the special sources and targets that begin with a dot,
with the notable exception of
Ic .PHONY ,
Ic .PRECIOUS ,
and
Ic .SUFFIXES .
It
Variable modifiers, except for the
Ql :old=new
string substitution, which does not portably support globbing with
Ql %
and historically only works on declared suffixes.
It
The
Ic $>
variable even in its short form; most makes support this functionality
but its name varies.
El
Pp
Some features are somewhat more portable, such as assignment with
Ic += ,
Ic ?= ,
and
Ic != .
The
Va .PATH
functionality is based on an older feature
Ic VPATH
found in GNU make and many versions of SVR4 make; however,
historically its behavior is too ill-defined (and too buggy) to rely
upon.
Pp
The
Ic $@
and
Ic $<
variables are more or less universally portable, as is the
Ic $(MAKE)
variable.
Basic use of suffix rules (for files only in the current directory,
not trying to chain transformations together, etc.) is also reasonably
portable.
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 Sprite at Berkeley.
It was designed to be a parallel distributed make running jobs on different
machines using a daemon called
Dq customs .
Pp
Historically the target/dependency
Ic FRC
has been used to FoRCe rebuilding (since the target/dependency
does not exist ... unless someone creates an
Pa FRC
file).
Sh BUGS
The
Nm
syntax is difficult to parse.
For instance, finding the end of a variable's use should involve scanning
each of 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.
Pp
In jobs mode, when a target fails;
Nm
will put an error token into the job token pool.
This will cause all other instances of
Nm
using that token pool to abort the build and exit with error code 6.
Sometimes the attempt to suppress a cascade of unnecessary errors,
can result in a seemingly unexplained
Ql *** Error code 6

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