BMAKE(1) | General Commands Manual | BMAKE(1) |
NAME¶
bmake
—
maintain program dependencies
SYNOPSIS¶
bmake |
[-BeikNnqrstWwX -C
directory-D
variable-d
flags-f
makefile-I
directory-J
private-j
max_jobs-m
directory-T
file-V
variablevariable=value ]
[target ... ] |
DESCRIPTION¶
bmake
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
-f
makefile makefile option is given,
bmake
will try to open
‘makefile
’
then
‘Makefile
’
in order to find the specifications. If the file
‘.depend
’
exists, it is read (see mkdep(1)).
This manual page is intended as a reference document only. For a more thorough
description of bmake
and makefiles, please
refer to PMake - A Tutorial.
bmake
will prepend the contents of the
MAKEFLAGS environment variable to the command
line arguments before parsing them.
The options are as follows:
-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.
-C
directory- Change to directory before reading the
makefiles or doing anything else. If multiple
-C
options are specified, each is interpreted relative to the previous one:-C
/-C
etc is equivalent to-C
/etc. -D
variable- Define variable to be 1, in the global context.
-d
[-]flags- Turn on debugging, and specify which portions of
bmake
are to print debugging information. Unless the flags are preceded by ‘-
’ they are added to the 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 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. Flags is one or more of the following:- A
- Print all possible debugging information; equivalent to specifying all of the debugging flags.
- a
- Print debugging information about archive searching and caching.
- C
- Print debugging information about current working directory.
- c
- Print debugging information about conditional evaluation.
- d
- Print debugging information about directory searching and caching.
- e
- Print debugging information about failed commands and targets.
- F[+]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 ‘
F
’ flag is ‘+
’, then the file will be opened in append mode; otherwise the file will be overwritten. If the file name is ‘stdout
’ or ‘stderr
’ then debugging output will be written to the standard output or standard error output file descriptors respectively (and the ‘+
’ option has no effect). Otherwise, the output will be written to the named file. If the file name ends ‘.%d
’ then the ‘%d
’ is replaced by the pid. - f
- Print debugging information about loop evaluation.
- g1
- Print the input graph before making anything.
- g2
- Print the input graph after making everything, or before exiting on error.
- g3
- Print the input graph before exiting on error.
- j
- Print debugging information about running multiple shells.
- l
- Print commands in Makefiles regardless of whether or not they are
prefixed by ‘
@
’ or other "quiet" flags. Also known as "loud" behavior. - M
- Print debugging information about "meta" mode decisions about targets.
- m
- Print debugging information about making targets, including modification dates.
- n
- Don't delete the temporary command scripts created when running
commands. These temporary scripts are created in the directory
referred to by the
TMPDIR
environment variable, or in /tmp ifTMPDIR
is unset or set to the empty string. The temporary scripts are created by mkstemp(3), and have names of the form makeXXXXXX. NOTE: This can create many files inTMPDIR
or /tmp, so use with care. - p
- Print debugging information about makefile parsing.
- s
- Print debugging information about suffix-transformation rules.
- t
- Print debugging information about target list maintenance.
- V
- Force the
-V
option to print raw values of variables. - v
- Print debugging information about variable assignment.
- w
- Print entering and leaving directory messages, pre and post processing.
- x
- Run shell commands with
-x
so the actual commands are printed as they are executed.
-e
- Specify that environment variables override macro assignments within makefiles.
-f
makefile- Specify a makefile to read instead of the default
‘
makefile
’. If makefile is ‘
’, standard input is read. Multiple makefiles may be specified, and are read in the order specified.-
-I
directory- Specify a directory in which to search for makefiles and included
makefiles. The system makefile directory (or directories, see the
-m
option) is automatically included as part of this list. -i
- Ignore non-zero exit of shell commands in the makefile. Equivalent to
specifying
‘
’ before each command line in the makefile.-
-J
private- This option should not be specified by the user. When the 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.
-j
max_jobs- Specify the maximum number of jobs that
bmake
may have running at any one time. The value is saved in .MAKE.JOBS. Turns compatibility mode off, unless the 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. -k
- Continue processing after errors are encountered, but only on those targets that do not depend on the target whose creation caused the error.
-m
directory- Specify a directory in which to search for sys.mk and makefiles included
via the ⟨file⟩-style
include statement. The
-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 “file”-style include statements (see the-I
option). If a file or directory name in the-m
argument (or theMAKESYSPATH
environment variable) starts with the string “.../” thenbmake
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 “.../” specification in the-m
argument. If used, this feature allowsbmake
to easily search in the current source tree for customized sys.mk files (e.g., by using “.../mk/sys.mk” as an argument). -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).
-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.
-q
- Do not execute any commands, but exit 0 if the specified targets are up-to-date and 1, otherwise.
-r
- Do not use the built-in rules specified in the system makefile.
-s
- Do not echo any commands as they are executed. Equivalent to specifying
‘
’ before each command line in the makefile.@
-T
tracefile- When used with the
-j
flag, append a trace record to tracefile for each job started and completed. -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.
-V
variable- Print
bmake
's idea of the value of 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 variable contains a ‘$
’ then the value will be expanded before printing. -W
- Treat any warnings during makefile parsing as errors.
-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 MAKEFLAGS environment variable. This option may be useful on systems which have a small limit on the size of command arguments.
- variable=value
- Set the value of the variable variable to
value. Normally, all values passed on the
command line are also exported to sub-makes in the environment. The
-X
flag disables this behavior. Variable assignments should follow options for POSIX compatibility but no ordering is enforced.
\
’). The trailing newline
character and initial whitespace on the following line are compressed into a
single space.
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 “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::
- 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
bmake
is interrupted. !
- 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
bmake
is interrupted. ::
- 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
bmake
is interrupted.
?
’,
‘*
’,
‘[]
’, and
‘{}
’. The values
‘?
’,
‘*
’, and
‘[]
’ 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 ‘{}
’ need not
necessarily be used to describe existing files. Expansion is in directory
order, not alphabetically as done in the shell.
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 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 ‘::
’
operator is used.
If the first characters of the command line are any combination of
‘@
’,
‘+
’,
or
‘-
’,
the command is treated specially. A
‘@
’
causes the command not to be echoed before it is executed. A
‘+
’
causes the command to be executed even when
-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
‘-
’
causes any non-zero exit status of the command line to be ignored.
When bmake
is run in jobs mode with
-j
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
(‘#=|^(){};&<>*?[]:$`\\n
’) it
will be passed to the shell, otherwise
bmake
will attempt direct execution.
Since bmake
will
chdir(2) to
‘.OBJDIR
’
before executing any targets, each child process starts with that as its
current working directory.
Makefiles should be written so that the mode of
bmake
operation does not change their
behavior. For example, any command which needs to use “cd” or
“chdir”, without side-effect should be put in parenthesis:
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`; \ (cd ${.CURDIR} && ${.MAKE} $@); \ echo Back in `pwd`
VARIABLE ASSIGNMENTS¶
Variables in make are much like variables in the shell, and, by tradition, consist of all upper-case letters.Variable assignment modifiers¶
The five operators that can be used to assign values to variables are as follows:=
- Assign the value to the variable. Any previous value is overridden.
+=
- Append the value to the current value of the variable.
?=
- Assign the value to the variable if it is not already defined.
:=
- Assign with expansion, i.e. expand the value before assigning it to the variable. Normally, expansion is not done until the variable is referenced. NOTE: References to undefined variables are not expanded. This can cause problems when variable modifiers are used.
!=
- Expand the value and pass it to the shell for execution and assign the result to the variable. Any newlines in the result are replaced with spaces.
{}
’) or parentheses
(‘()
’) and preceding it with a dollar
sign (‘$
’). If the variable name
contains only a single letter, the surrounding braces or parentheses are not
required. This shorter form is not recommended.
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!
If the result of expanding a variable contains a dollar sign
(‘$
’) the string is expanded again.
Variable substitution occurs at three distinct times, depending on where the
variable is being used.
- Variables in dependency lines are expanded as the line is read.
- Variables in shell commands are expanded when the shell command is executed.
- “.for” loop index variables are expanded on each loop
iteration. Note that other variables are not expanded inside loops so the
following example code:
.for i in 1 2 3
a+= ${i} j= ${i} b+= ${j}.endfor
all: @echo ${a} @echo ${b}1 2 3 3 3 3
Variable classes¶
The four different classes of variables (in order of increasing precedence) are:- Environment variables
- Variables defined as part of
bmake
's environment. - Global variables
- Variables defined in the makefile or in included makefiles.
- Command line variables
- Variables defined as part of the command line.
- Local variables
- Variables that are defined specific to a certain target. The seven local
variables are as follows:
- .ALLSRC
- The list of all sources for this target; also known as
‘
>
’. - .ARCHIVE
- The name of the archive file.
- .IMPSRC
- In suffix-transformation rules, the name/path of the source from which
the target is to be transformed (the “implied” source);
also known as
‘
<
’. It is not defined in explicit rules. - .MEMBER
- The name of the archive member.
- .OODATE
- The list of sources for this target that were deemed out-of-date; also
known as
‘
?
’. - .PREFIX
- The file prefix of the target, containing only the file portion, no
suffix or preceding directory components; also known as
‘
*
’. - .TARGET
- The name of the target; also known as
‘
@
’.
@
’, ‘?
’, ‘<
’, ‘>
’, and ‘*
’ are permitted for backward compatibility with historical makefiles and are not recommended. The six variables ‘@F
’, ‘@D
’, ‘<F
’, ‘<D
’, ‘*F
’, and ‘*D
’ are permitted for compatibility with AT&T System V UNIX makefiles and are not recommended. 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 ‘.TARGET
’, ‘.PREFIX
’, ‘.ARCHIVE
’, and ‘.MEMBER
’.
Additional built-in variables¶
In addition,bmake
sets or knows about the
following variables:
- $
- A single dollar sign ‘
$
’, i.e. ‘$$
’ expands to a single dollar sign. - .ALLTARGETS
- The list of all targets encountered in the Makefile. If evaluated during Makefile parsing, lists only those targets encountered thus far.
- .CURDIR
- A path to the directory where
bmake
was executed. Refer to the description of ‘
’ for more details.PWD
- .INCLUDEDFROMDIR
- The directory of the file this Makefile was included from.
- .INCLUDEDFROMFILE
- The filename of the file this Makefile was included from.
MAKE
- The name that
bmake
was executed with (argv[0]). For compatibilitybmake
also sets .MAKE with the same value. The preferred variable to use is the environment variableMAKE
because it is more compatible with other versions ofbmake
and cannot be confused with the special target with the same name. - .MAKE.DEPENDFILE
- Names the makefile (default
‘
.depend
’) from which generated dependencies are read. - .MAKE.EXPAND_VARIABLES
- A boolean that controls the default behavior of the
-V
option. - .MAKE.EXPORTED
- The list of variables exported by
bmake
. - .MAKE.JOBS
- The argument to the
-j
option. - .MAKE.JOB.PREFIX
- If
bmake
is run with j then output for each target is prefixed with a token ‘--- target ---
’ the first part of which can be controlled via .MAKE.JOB.PREFIX. If .MAKE.JOB.PREFIX is empty, no token is printed..MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
would produce tokens like ‘---make[1234] target ---
’ making it easier to track the degree of parallelism being achieved. MAKEFLAGS
- The environment variable
‘
’ may contain anything that may be specified onMAKEFLAGS
bmake
's command line. Anything specified onbmake
's command line is appended to the ‘
’ variable which is then entered into the environment for all programs whichMAKEFLAGS
bmake
executes. - .MAKE.LEVEL
- The recursion depth of
bmake
. The initial instance ofbmake
will be 0, and an incremented value is put into the environment to be seen by the next generation. This allows tests like:.if ${.MAKE.LEVEL} == 0
to protect things which should only be evaluated in the initial instance ofbmake
. - .MAKE.MAKEFILE_PREFERENCE
- The ordered list of makefile names (default
‘
makefile
’, ‘Makefile
’) thatbmake
will look for. - .MAKE.MAKEFILES
- The list of makefiles read by
bmake
, which is useful for tracking dependencies. Each makefile is recorded only once, regardless of the number of times read. - .MAKE.MODE
- Processed after reading all makefiles. Can affect the mode that
bmake
runs in. It can contain a number of keywords:- compat
- Like
-B
, putsbmake
into "compat" mode. - meta
- Puts
bmake
into "meta" mode, where meta files are created for each target to capture the command run, the output generated and if filemon(4) is available, the system calls which are of interest tobmake
. The captured output can be very useful when diagnosing errors. - curdirOk= bf
- Normally
bmake
will not create .meta files in ‘.CURDIR
’. This can be overridden by setting bf to a value which represents True. - env
- For debugging, it can be useful to inlcude the environment in the .meta file.
- 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: .MAKE.META.PREFIX.
- 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
.NOMETA_CMP
. - silent= bf
- If bf is True, when a .meta file is
created, mark the target
.SILENT
.
- .MAKE.META.BAILIWICK
- In "meta" mode, provides a list of prefixes which match the
directories controlled by
bmake
. If a file that was generated outside of .OBJDIR but within said bailiwick is missing, the current target is considered out-of-date. - .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 .MAKE.META.FILES.
- .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.
- .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:
‘
/dev /etc /proc /tmp /var/run /var/tmp
’ - .MAKE.META.PREFIX
- Defines the message printed for each meta file updated in "meta
verbose" mode. The default value is:
Building ${.TARGET:H:tA}/${.TARGET:T}
- .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
‘
’. This behaviour can be disabled by assigning an empty value to ‘MAKEFLAGS
.MAKEOVERRIDES
’ within a makefile. Extra variables can be exported from a makefile by appending their names to ‘.MAKEOVERRIDES
’. ‘
’ is re-exported whenever ‘MAKEFLAGS
.MAKEOVERRIDES
’ is modified. - .MAKE.PATH_FILEMON
- If
bmake
was built with filemon(4) support, this is set to the path of the device node. This allows makefiles to test for this support. - .MAKE.PID
- The process-id of
bmake
. - .MAKE.PPID
- The parent process-id of
bmake
. - MAKE_PRINT_VAR_ON_ERROR
- When
bmake
stops due to an error, it prints its name and the value of ‘.CURDIR
’ as well as the value of any variables named in ‘MAKE_PRINT_VAR_ON_ERROR
’. - .newline
- This variable is simply assigned a newline character as its value. This
allows expansions using the
:@
modifier to put a newline between iterations of the loop rather than a space. For example, the printing of ‘MAKE_PRINT_VAR_ON_ERROR
’ could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}. - .OBJDIR
- A path to the directory where the targets are built. Its value is
determined by trying to chdir(2) to the
following directories in order and using the first match:
${MAKEOBJDIRPREFIX}${.CURDIR}
(Only if ‘
’ is set in the environment or on the command line.)MAKEOBJDIRPREFIX
${MAKEOBJDIR}
(Only if ‘
’ is set in the environment or on the command line.)MAKEOBJDIR
${.CURDIR}
/obj.${MACHINE}
${.CURDIR}
/obj- /usr/obj/
${.CURDIR}
${.CURDIR}
may be used. This is especially useful with ‘${.CURDIR:S,^/usr/src,/var/obj,}
’. ‘MAKEOBJDIR
.OBJDIR
’ may be modified in the makefile as a global variable. In all cases,bmake
will chdir(2) to ‘.OBJDIR
’ and set ‘
’ to that directory before executing any targets.PWD
- .PARSEDIR
- A path to the directory of the current
‘
Makefile
’ being parsed. - .PARSEFILE
- The basename of the current
‘
Makefile
’ being parsed. This variable and ‘.PARSEDIR
’ are both set only while the ‘Makefiles
’ are being parsed. If you want to retain their current values, assign them to a variable using assignment with expansion: (‘
’).:=
- .PATH
- A variable that represents the list of directories that
bmake
will search for files. The search list should be updated using the target ‘.PATH
’ rather than the variable. PWD
- Alternate path to the current directory.
bmake
normally sets ‘.CURDIR
’ to the canonical path given by getcwd(3). However, if the environment variable ‘
’ is set and gives a path to the current directory, thenPWD
bmake
sets ‘.CURDIR
’ to the value of ‘
’ instead. This behaviour is disabled if ‘PWD
’ is set or ‘MAKEOBJDIRPREFIX
’ contains a variable transform. ‘MAKEOBJDIR
’ is set to the value of ‘PWD
.OBJDIR
’ for all programs whichbmake
executes. .TARGETS
- The list of targets explicitly specified on the command line, if any.
VPATH
- Colon-separated (“:”) lists of directories that
bmake
will search for files. The variable is supported for compatibility with old make programs only, use ‘.PATH
’ instead.
Variable modifiers¶
Variable expansion may be modified to select or modify each word of the variable (where a “word” is white-space delimited sequence of characters). The general format of a variable expansion is as follows:${variable[:modifier[:...]]}
\
’).
A set of modifiers can be specified via a variable, as follows:
modifier_variable=modifier[:...]
${variable:${modifier_variable}[:...]}
$
’), these must be doubled to avoid
early expansion.
The supported modifiers are:
:E
- Replaces each word in the variable with its suffix.
:H
- Replaces each word in the variable with everything but the last component.
:M
pattern- Select only those words that match
pattern. The standard shell wildcard
characters (‘
*
’, ‘?
’, and ‘[]
’) may be used. The wildcard characters may be escaped with a backslash (‘\
’). As a consequence of the way values are split into words, matched, and then joined, a construct likewill normalise the inter-word spacing, removing all leading and trailing space, and converting multiple consecutive spaces to single spaces.${VAR:M*}
:N
pattern- This is identical to
‘
’, but selects all words which do not match pattern.:M
:O
- Order every word in variable alphabetically. To sort words in reverse
order use the
‘
’ combination of modifiers.:O:[-1..1]
:Ox
- Randomize words in variable. The results will be different each time you
are referring to the modified variable; use the assignment with expansion
(‘
’) to prevent such behaviour. For example,:=
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 "${STATIC_RANDOM_LIST}"
quattro due tre uno tre due quattro uno due uno quattro tre due uno quattro tre
:Q
- Quotes every shell meta-character in the variable, so that it can be
passed safely through recursive invocations of
bmake
. :R
- Replaces each word in the variable with everything but its suffix.
:gmtime
- The value is a format string for strftime(3), using the current gmtime(3).
:hash
- Compute a 32bit hash of the value and encode it as hex digits.
:localtime
- The value is a format string for strftime(3), using the current localtime(3).
:tA
- Attempt to convert variable to an absolute path using realpath(3), if that fails, the value is unchanged.
:tl
- Converts variable to lower-case letters.
:ts
c- Words in the variable are normally separated by a space on expansion. This modifier sets the separator to the character c. If c is omitted, then no separator is used. The common escapes (including octal numeric codes), work as expected.
:tu
- Converts variable to upper-case letters.
:tW
- Causes the value to be treated as a single word (possibly containing
embedded white space). See also
‘
’.:[*]
:tw
- Causes the value to be treated as a sequence of words delimited by white
space. See also
‘
’.:[@]
:S
/old_string/new_string/[]1gW
- Modify the first occurrence of
old_string in the variable's value,
replacing it with new_string. If a
‘
g
’ is appended to the last slash of the pattern, all occurrences in each word are replaced. If a ‘1
’ is appended to the last slash of the pattern, only the first word is affected. If a ‘W
’ is appended to the last slash of the pattern, then the value is treated as a single word (possibly containing embedded white space). If old_string begins with a caret (‘^
’), old_string is anchored at the beginning of each word. If old_string ends with a dollar sign (‘$
’), it is anchored at the end of each word. Inside new_string, an ampersand (‘&
’) is replaced by old_string (without any ‘^
’ or ‘$
’). 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 (‘\
’). Variable expansion occurs in the normal fashion inside both old_string and new_string with the single exception that a backslash is used to prevent the expansion of a dollar sign (‘$
’), not a preceding dollar sign as is usual. :C
/pattern/replacement/[]1gW
- The
:C
modifier is just like the:S
modifier except that the old and new strings, instead of being simple strings, are an extended regular expression (see regex(3)) string pattern and an ed(1)-style string replacement. Normally, the first occurrence of the pattern pattern in each word of the value is substituted with replacement. The ‘1
’ modifier causes the substitution to apply to at most one word; the ‘g
’ modifier causes the substitution to apply to as many instances of the search pattern pattern as occur in the word or words it is found in; the ‘W
’ modifier causes the value to be treated as a single word (possibly containing embedded white space). Note that ‘1
’ and ‘g
’ are orthogonal; the former specifies whether multiple words are potentially affected, the latter whether multiple substitutions can potentially occur within each affected word. As for the:S
modifier, the pattern and replacement are subjected to variable expansion before being parsed as regular expressions. :T
- Replaces each word in the variable with its last component.
:u
- Remove adjacent duplicate words (like uniq(1)).
:?
true_string:
false_string- If the variable name (not its value), when parsed as a .if conditional
expression, evaluates to true, return as its value the
true_string, otherwise return the
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
which actually tests defined(NUMBERS), to determine is any words match "42" you need to use something like:
${NUMBERS:M42:?match:no}
${"${NUMBERS:M42}" != "":?match:no}.
- :old_string=new_string
- This is the AT&T System V UNIX style
variable substitution. It must be the last modifier specified. If
old_string or
new_string do not contain the pattern
matching character % then it is assumed
that they are anchored at the end of each word, so only suffixes or entire
words may be replaced. Otherwise % is the
substring of old_string to be replaced in
new_string.
Variable expansion occurs in the normal fashion inside both
old_string and
new_string with the single exception that
a backslash is used to prevent the expansion of a dollar sign
(‘
$
’), not a preceding dollar sign as is usual. :@
temp@
string@
- This is the loop expansion mechanism from the OSF Development Environment
(ODE) make. Unlike
.for
loops expansion occurs at the time of reference. Assign temp to each word in the variable and evaluate string. The ODE convention is that temp should start and end with a period. For example.However a single character variable is often more readable:${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
:U
newval- If the variable is undefined 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:
If a value is only required if the variable is undefined, use:
${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
${VAR:D:Unewval}
:D
newval- If the variable is defined newval is the value.
:L
- The name of the variable is the value.
: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. In order for this modifier to work, the name (node) must at least have appeared on the rhs of a dependency.
:!
cmd!
- The output of running cmd is the value.
:sh
- If the variable is non-empty it is run as a command and the output becomes the new value.
::=
str- The variable is assigned the value 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
bmake
happy. The ‘
’ helps avoid false matches with the AT&T System V UNIX style::
:=
modifier and since substitution always occurs the::=
form is vaguely appropriate. ::?=
str- As for
::=
but only if the variable does not already have a value. ::+=
str- Append str to the variable.
::!=
cmd- Assign the output of cmd to the variable.
:[
range]
- Selects one or more words from the value, or performs other operations
related to the way in which the value is divided into words.
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
‘
’ 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). The range is subjected to variable expansion, and the expanded result is then interpreted as follows::[]
- index
- Selects a single word from the value.
- start
..
end - Selects all words from start to
end, inclusive. For example,
‘
’ selects all words from the second word to the last word. If start is greater than end, then the words are output in reverse order. For example, ‘:[2..-1]
’ selects all the words from last to first.:[-1..1]
*
- 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
- Means the same as
‘
’.:[*]
@
- Causes subsequent modifiers to treat the value as a sequence of words delimited by white space. Analogous to the effect of "$@" in Bourne shell.
#
- Returns the number of words in the value.
INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS¶
Makefile inclusion, conditional structures and for loops reminiscent of the C programming language are provided inbmake
.
All such structures are identified by a line beginning with a single dot
(‘.
’) character. Files are included with
either .include
⟨file⟩ or
.include
"file". 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
-I
option are searched before the system
makefile directory. For compatibility with other versions of
bmake
‘include file
...
’ is also accepted. If the include statement is written as
.-include
or as
.sinclude
then errors locating and/or
opening include files are ignored.
Conditional expressions are also preceded by a single dot as the first character
of a line. The possible conditionals are as follows:
.error
message- The message is printed along with the name of the makefile and line
number, then
bmake
will exit. .export
variable ...- Export the specified global variable. If no variable list is provided, all
globals are exported except for internal variables (those that start with
‘
.
’). This is not affected by the-X
flag, so should be used with caution. For compatibility with otherbmake
programs ‘export variable=value
’ is also accepted. Appending a variable name to .MAKE.EXPORTED is equivalent to exporting a variable. .export-env
variable ...- The same as ‘
.export
’, except that the variable is not appended to .MAKE.EXPORTED. This allows exporting a value to the environment which is different from that used bybmake
internally. .info
message- The message is printed along with the name of the makefile and line number.
.undef
variable- Un-define the specified global variable. Only global variables may be un-defined.
.unexport
variable ...- The opposite of ‘
.export
’. The specified global variable will be removed from .MAKE.EXPORTED. If no variable list is provided, all globals are unexported, and .MAKE.EXPORTED deleted. .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
.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:
.if ${.MAKE.LEVEL} == 0
PATH := ${PATH}.unexport-env
.export PATH
.endif
’, which is the minimal useful environment. Actually ‘PATH
’ will also be pushed into the new environment..MAKE.LEVEL
.warning
message- The message prefixed by
‘
warning:
’ is printed along with the name of the makefile and line number. .if
[!]expression [operator expression ...]- Test the value of an expression.
.ifdef
[!]variable [operator variable ...]- Test the value of a variable.
.ifndef
[!]variable [operator variable ...]- Test the value of a variable.
.ifmake
[!]target [operator target ...]- Test the target being built.
.ifnmake
[!] target [operator target ...]- Test the target being built.
.else
- Reverse the sense of the last conditional.
.elif
[!] expression [operator expression ...]- A combination of
‘
’ followed by ‘.else
’..if
.elifdef
[!]variable [operator variable ...]- A combination of
‘
’ followed by ‘.else
’..ifdef
.elifndef
[!]variable [operator variable ...]- A combination of
‘
’ followed by ‘.else
’..ifndef
.elifmake
[!]target [operator target ...]- A combination of
‘
’ followed by ‘.else
’..ifmake
.elifnmake
[!]target [operator target ...]- A combination of
‘
’ followed by ‘.else
’..ifnmake
.endif
- End the body of the conditional.
bmake
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
‘!
’
may be used to logically negate an entire conditional. It is of higher
precedence than
‘&&
’.
The value of expression may be any of the
following:
defined
- Takes a variable name as an argument and evaluates to true if the variable has been defined.
make
- Takes a target name as an argument and evaluates to true if the target was
specified as part of
bmake
's command line or was declared the default target (either implicitly or explicitly, see .MAIN) before the line containing the conditional. empty
- Takes a variable, with possible modifiers, and evaluates to true if the expansion of the variable would result in an empty string.
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 .PATH).
target
- Takes a target name as an argument and evaluates to true if the target has been defined.
commands
- Takes a target name as an argument and evaluates to true if the target has been defined and has commands associated with it.
==
’
or
‘!=
’
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.
When bmake
is evaluating one of these
conditional expressions, and it encounters a (white-space separated) word it
doesn't recognize, either the “make” or “defined”
expression is applied to it, depending on the form of the conditional. If the
form is
‘.ifdef
’,
‘.ifndef
’,
or
‘.if
’
the “defined” expression is applied. Similarly, if the form is
‘.ifmake
’
or ‘.ifnmake
,
the
’ “make”
expression is applied.
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
‘.else
’
or
‘.endif
’
is found.
For loops are typically used to apply a set of rules to a list of files. The
syntax of a for loop is:
After the for expression
is evaluated, it is
split into words. On each iteration of the loop, one word is taken and
assigned to each variable
, in order, and
these variables
are substituted into the
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.
COMMENTS¶
Comments begin with a hash (‘#
’)
character, anywhere but in a shell command line, and continue to the end of an
unescaped new line.
SPECIAL SOURCES (ATTRIBUTES)¶
.EXEC
- Target is never out of date, but always execute commands anyway.
.IGNORE
- Ignore any errors from the commands associated with this target, exactly
as if they all were preceded by a dash
(‘
-
’). .MADE
- Mark all sources of this target as being up-to-date.
.MAKE
- Execute the commands associated with this target even if the
-n
or-t
options were specified. Normally used to mark recursivebmake
s. .META
- Create a meta file for the target, even if it is flagged as
.PHONY
,.MAKE
, or.SPECIAL
. Usage in conjunction with.MAKE
is the most likely case. In "meta" mode, the target is out-of-date if the meta file is missing. .NOMETA
- Do not create a meta file for the target. Meta files are also not created
for
.PHONY
,.MAKE
, or.SPECIAL
targets. .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. The same effect applies to any command line that uses the variable
.OODATE, which can be used for that
purpose even when not otherwise needed or desired:
skip-compare-for-some: @echo this will be compared @echo this will not ${.OODATE:M.NOMETA_CMP} @echo this will also be compared
:M
pattern suppresses any expansion of the unwanted variable. .NOPATH
- Do not search for the target in the directories specified by
.PATH
. .NOTMAIN
- Normally
bmake
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. .OPTIONAL
- If a target is marked with this attribute and
bmake
can't figure out how to create it, it will ignore this fact and assume the file isn't needed or already exists. .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
-t
option. Suffix-transformation rules are not applied to.PHONY
targets. .PRECIOUS
- When
bmake
is interrupted, it normally removes any partially made targets. This source prevents the target from being removed. .RECURSIVE
- Synonym for
.MAKE
. .SILENT
- Do not echo any of the commands associated with this target, exactly as if
they all were preceded by an at sign
(‘
@
’). .USE
- Turn the target into
bmake
'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.USE
) of the source. If the target already has commands, the.USE
target's commands are appended to them. .USEBEFORE
- Exactly like
.USE
, but prepend the.USEBEFORE
target commands to the target. .WAIT
- If
.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:x: a .WAIT b echo x a: echo a b: b1 echo b b1: echo b1
a
’, ‘b1
’, ‘b
’, ‘x
’..WAIT
is only relevant for parallel makes.
SPECIAL TARGETS¶
Special targets may not be included with other targets, i.e. they must be the only target specified..BEGIN
- Any command lines attached to this target are executed before anything else is done.
.DEFAULT
- This is sort of a
.USE
rule for any target (that was used only as a source) thatbmake
can't figure out any other way to create. Only the shell script is used. The.IMPSRC
variable of a target that inherits.DEFAULT
's commands is set to the target's own name. .END
- Any command lines attached to this target are executed after everything else is done.
.ERROR
- Any command lines attached to this target are executed when another target
fails. The
.ERROR_TARGET
variable is set to the target that failed. See alsoMAKE_PRINT_VAR_ON_ERROR
. .IGNORE
- Mark each of the sources with the
.IGNORE
attribute. If no sources are specified, this is the equivalent of specifying the-i
option. .INTERRUPT
- If
bmake
is interrupted, the commands for this target will be executed. .MAIN
- If no target is specified when
bmake
is invoked, this target will be built. .MAKEFLAGS
- This target provides a way to specify flags for
bmake
when the makefile is used. The flags are as if typed to the shell, though the-f
option will have no effect. .NOPATH
- Apply the
.NOPATH
attribute to any specified sources. .NOTPARALLEL
- Disable parallel mode.
.NO_PARALLEL
- Synonym for
.NOTPARALLEL
, for compatibility with other pmake variants. .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
‘
a
’ is built by another part of the dependency graph, the following is a dependency loop:.ORDER: b a b: a
.ORDER
is only relevant for parallel makes. .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
.DOTLAST
target, then the current working directory is searched last. .PATH.
suffix- Like
.PATH
but applies only to files with a particular suffix. The suffix must have been previously declared with.SUFFIXES
. .PHONY
- Apply the
.PHONY
attribute to any specified sources. .PRECIOUS
- Apply the
.PRECIOUS
attribute to any specified sources. If no sources are specified, the.PRECIOUS
attribute is applied to every target in the file. .SHELL
- Sets the shell that
bmake
will use to execute commands. The sources are a set of field=value pairs.- name
- This is the minimal specification, used to select one of the builtin shell specs; sh, ksh, and csh.
- path
- Specifies the path to the shell.
- hasErrCtl
- Indicates whether the shell supports exit on error.
- check
- The command to turn on error checking.
- ignore
- The command to disable error checking.
- echo
- The command to turn on echoing of commands executed.
- quiet
- The command to turn off echoing of commands executed.
- filter
- The output to filter after issuing the quiet command. It is typically identical to quiet.
- errFlag
- The flag to pass the shell to enable error checking.
- echoFlag
- The flag to pass the shell to enable command echoing.
- newline
- The string literal to pass the shell that results in a single newline character when used outside of any quoting characters.
.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \ check="set -e" ignore="set +e" \ echo="set -v" quiet="set +v" filter="set +v" \ echoFlag=v errFlag=e newline="'\n'"
.SILENT
- Apply the
.SILENT
attribute to any specified sources. If no sources are specified, the.SILENT
attribute is applied to every command in the file. .STALE
- This target gets run when a dependency file contains stale entries, having .ALLSRC set to the name of that dependency file.
.SUFFIXES
- Each source specifies a suffix to
bmake
. If no sources are specified, any previously specified suffixes are deleted. It allows the creation of suffix-transformation rules. Example:.SUFFIXES: .o .c.o: cc -o ${.TARGET} -c ${.IMPSRC}
ENVIRONMENT¶
bmake
uses the following environment
variables, if they exist: MACHINE
,
MACHINE_ARCH
,
MACHINE_MULTIARCH
,
MAKE
,
MAKEFLAGS
,
MAKEOBJDIR
,
MAKEOBJDIRPREFIX
,
MAKESYSPATH
,
PWD
, and
TMPDIR
.
MAKEOBJDIRPREFIX
and
MAKEOBJDIR
may only be set in the
environment or on the command line to bmake
and not as makefile variables; see the description of
‘.OBJDIR
’
for more details.
FILES¶
- .depend
- list of dependencies
- Makefile
- list of dependencies
- makefile
- list of dependencies
- sys.mk
- system makefile
- /usr/share/mk
- system makefile directory
COMPATIBILITY¶
The basic make syntax is compatible between different versions of make, however the special variables, variable modifiers and conditionals are not. The way that parallel makes are scheduled changed in NetBSD 4.0 so that .ORDER and .WAIT apply recursively to the dependent nodes. The algorithms used may change again in the future. The way that .for loop variables are substituted changed after NetBSD 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.SEE ALSO¶
mkdep(1)HISTORY¶
bmake
is derived from NetBSD
make(1). It uses autoconf to facilitate
portability to other platforms.
A make command appeared in Version 7 AT&T
UNIX. This make 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
“customs”.
Historically the target/dependency “FRC” has been used to FoRCe
rebuilding (since the target/dependency does not exist... unless someone
creates an “FRC” file).
BUGS¶
The make 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 make just counts {} and () in order to find the end of a variable expansion. There is no way of escaping a space character in a filename.February 14, 2014 | Debian |