is a program designed to simplify the maintenance of other pro- grams. Its input is a list of specifications as to the files upon which programs and other files depend. If no option is given, tries to open then in order to find the specifications. If the file exists, it is read, see This manual page is intended as a reference document only. For a more thorough description of and makefiles, please refer to (from 1993). prepends the con- tents of the environment variable to the command line arguments before parsing them. The options are as follows: Try to be back- wards compatible by executing a single shell per command and by making the sources of a dependency line in sequence. Change to before reading the makefiles or doing anything else. If multiple options are specified, each is interpreted relative to the previ- ous one: is equivalent to Define to be 1, in the global scope. Turn on debugging, and specify which portions of are to print de- bugging information. Unless the flags are preceded by they are added to the 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 debugging flag. The debugging output is always unbuffered; in addition, if debug- ging is enabled but debugging output is not directed to standard output, the standard output is line buffered. The available are: Print all possible debugging information; equivalent to specify- ing all of the debugging flags. Print debugging information about archive searching and caching. Print debugging information about the current working directory. Print debugging information about conditional evaluation. Print debugging information about directory searching and caching. Print debugging information about failed commands and targets. Specify where debugging out- put is written. This must be the last flag, because it consumes the remainder of the argument. If the character immediately af- ter the flag is the file is opened in append mode; otherwise the file is overwritten. If the file name is or debugging output is written to the standard output or standard error output respec- tively (and the option has no effect). Otherwise, the output is written to the named file. If the file name ends with the is re- placed by the pid. Print debugging information about loop evalu- ation. Print the input graph before making anything. Print the input graph after making everything, or before exiting on error. Print the input graph before exiting on error. Print debugging information about hash table operations. Print debugging infor- mation about running multiple shells. Turn on lint checks. This throws errors for variable assignments that do not parse cor- rectly, at the time of assignment, so the file and line number are available. Print commands in Makefiles regardless of whether or not they are prefixed by or other flags. Also known as behav- ior. Print debugging information about mode decisions about tar- gets. Print debugging information about making targets, includ- ing modification dates. Don't delete the temporary command scripts created when running commands. These temporary scripts are created in the directory referred to by the environment vari- able, or in if is unset or set to the empty string. The tempo- rary scripts are created by and have names of the form This can create many files in or so use with care. Print debugging infor- mation about makefile parsing. Print debugging information about suffix-transformation rules. Print debugging information about target list maintenance. Force the option to print raw values of variables, overriding the default behavior set via Print debug- ging information about variable assignment and expansion. Run shell commands with so the actual commands are printed as they are executed. Let environment variables override global vari- ables within makefiles. Specify a makefile to read instead of the default or If is standard input is read. Multiple makefiles may be specified, and are read in the order specified. Specify a directory in which to search for makefiles and included make- files. The system makefile directory (or directories, see the option) is automatically included as part of this list. Ignore non-zero exit of shell commands in the makefile. Equivalent to specifying before each command line in the makefile. This option should be specified by the user. When the 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. Specify the maximum number of jobs that may have running at any one time. If is a floating point number, or ends with then the value is multiplied by the number of CPUs reported online by The value of is saved in Turns compat- ibility mode off, unless the option is also specified. When com- patibility mode is off, all commands associated with a target are executed in a single shell invocation as opposed to the tradi- tional 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. A job token pool with tokens is used to control the total number of jobs running. Each instance of will wait for a token from the pool before running a new job. Continue processing after errors are encountered, but only on those targets that do not depend on the target whose creation caused the error. Specify a directory in which to search for and makefiles included via the include statement. The option can be used multiple times to form a search path. This path overrides the default system include path Furthermore, the system include path is appended to the search path used for include statements (see the option). The system include path can be referenced via the read-only variable If a directory name in the argument (or the environment variable) starts with the string 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 specification in the argument. This feature allows to easily search in the current source tree for customized files (e.g., by using as an argument). Display the commands that would have been executed, but do not actually execute them unless the target de- pends on the special source (see below) or the command is pre- fixed with 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. Do not execute any commands, instead exit 0 if the specified targets are up to date, and 1 otherwise. Do not use the built-in rules specified in the system makefile. Stop processing if an error is encountered. This is the default behavior and the opposite of Do not echo any commands as they are executed. Equivalent to speci- fying before each command line in the makefile. When used with the flag, append a trace record to for each job started and com- pleted. 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. Print the value of 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 un- defined variable. The value printed is extracted from the global scope after all makefiles have been read. By default, the raw variable contents (which may include additional unexpanded vari- able references) are shown. If contains a it is not interpreted as a variable name but rather as an expression. Its value is ex- panded before printing. The value is also expanded before print- ing if is set to true and the option has not been used to over- ride it. Note that loop-local and target-local variables, as well as values taken temporarily by global variables during make- file processing, are not accessible via this option. The debug mode can be used to see these at the cost of generating substan- tial extraneous output. Like but all printed variables are al- ways expanded to their complete value. The last occurrence of or decides whether all variables are expanded or not. Treat any warnings during makefile parsing as errors. Print entering and leaving directory messages, pre and post processing. Don't ex- port variables passed on the command line to the environment in- dividually. Variables passed on the command line are still ex- ported via the environment variable. This option may be useful on systems which have a small limit on the size of command argu- ments. Set the value of the variable to Normally, all values passed on the command line are also exported to sub-makes in the environment. The flag disables this behavior. Variable assign- ments should follow options for POSIX compatibility but no order- ing is enforced. There are several different types of lines in a makefile: dependency specifications, shell commands, variable as- signments, include statements, conditional directives, for loops, other directives, and comments. Lines may be continued from one line to the next by ending them with a backslash The trailing newline character and initial whitespace on the following line are compressed into a single space. Dependency lines consist of one or more targets, an operator, and zero or more sources. This creates a relationship where the targets 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 them- selves re-created as needed. Three operators may be used: Many dependency lines may name this target but only one may have at- tached shell commands. All sources named in all dependency lines are considered together, and if needed the attached shell com- mands are run to create or re-create the target. If is inter- rupted, the target is removed. The same, but the target is al- ways re-created whether or not it is out of date. 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. Fur- thermore, unlike for dependency lines with no sources, the at- tached shell commands are always run. Also unlike the target is not removed if is interrupted. All dependency lines mentioning a particular target must use the same operator. Targets and sources may contain the shell wildcard values and The values and may only be used as part of the final component of the target or source, and only match existing files. The value need not neces- sarily be used to describe existing files. Expansion is in di- rectory order, not alphabetically as done in the shell. 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 be preceded by a tab. (For historical reasons, spaces are not accepted.) While targets can occur in many depen- dency lines if desired, by default only one of these rules may be followed by a creation script. If the operator is used, however, all rules may include scripts, and the respective scripts are ex- ecuted in the order found. Each line is treated as a separate shell command, unless the end of line is escaped with a backslash in which case that line and the next are combined. If the first characters of the command are any combination of or the command is treated specially. causes the command not to be echoed before it is executed. causes the command to be executed even when is given. This is similar to the effect of the special source, ex- cept that the effect can be limited to a single line of a script. in compatibility mode causes any non-zero exit status of the com- mand line to be ignored. When is run in jobs mode with the en- tire 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 char- acters it is passed to the shell; otherwise attempts direct exe- cution. If a line starts with and the shell has ErrCtl enabled, failure of the command line is ignored as in compatibility mode. Otherwise affects the entire job; the script stops at the first command line that fails, but the target is not deemed to have failed. Makefiles should be written so that the mode of opera- tion does not change their behavior. For example, any command which uses or 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 ex- ample: 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)" Since changes the current working directory to before executing any targets, each child process starts with that as its current working directory. Variables in make behave much like macros in the C preprocessor. Variable as- signments have the form where: is a single-word variable name, consisting, by tradition, of all upper-case letters, is one of the variable assignment operators described below, and is inter- preted according to the variable assignment operator. Whitespace around and is discarded. The five operators that assign values to variables are: Assign the value to the variable. Any previous value is overwritten. Append the value to the current value of the variable, separating them by a single space. Assign the value to the variable if it is not already defined. Expand the value, then assign it to the variable. References to undefined variables are expanded. This can cause problems when variable modifiers are used. 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. In most contexts where variables are expanded, ex- pands to a single dollar sign. In other contexts (most variable modifiers, string literals in conditions), expands to a single dollar sign. References to variables have the form or If the variable name consists of only a single character and the expres- sion contains no modifiers, the surrounding curly braces or parentheses are not required. This shorter form is not recom- mended. 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 white- space are really best avoided. If the result of expanding a nested variable expression contains a dollar sign the result is subject to further expansion. Variable substitution occurs at four distinct times, depending on where the variable is being used. Variables in dependency lines are expanded as the line is read. Variables in conditionals are expanded individually, but only as far as necessary to determine the result of the condi- tional. Variables in shell commands are expanded when the shell command is executed. 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: .for i in 1 2 3 a+= ${i} j= ${i} b+= ${j} .endfor all: @echo ${a} @echo ${b} prints: 1 2 3 3 3 3 After the loop is executed: contains which expands to contains which expands to contains which expands to and further to The four different classes of variables (in order of increasing precedence) are: Variables defined as part of environment. Vari- ables defined in the makefile or in included makefiles. Vari- ables defined as part of the command line. Variables that are defined specific to a certain target. Local variables can be set on a dependency line, unless is set to The rest of the line (which already has had global variables expanded) is the variable value. For example: COMPILER_WRAPPERS= ccache distcc icecc ${OBJS}: .MAKE.META.CMP_FILTER=${COMPILER_WRAPPERS:S,^,N,} Only the targets are impacted by that filter (in mode) and simply en- abling/disabling any of the compiler wrappers does not render all of those targets out-of-date. target-local variable assignments behave differently in that; Only appends to a previous local as- signment for the same target and variable. Is redundant with re- spect to global variables, which have already been expanded. The seven built-in local variables are: The list of all sources for this target; also known as The name of the archive file; also known as In suffix-transformation rules, the name/path of the source from which the target is to be transformed (the source); also known as It is not defined in explicit rules. The name of the archive member; also known as The list of sources for this target that were deemed out-of-date; also known as The name of the target with suffix (if declared in removed; also known as The name of the target; also known as For compatibility with other makes this is an alias for in archive member rules. The shorter forms and are permitted for backward compatibility with histori- cal makefiles and legacy POSIX make and are not recommended. Variants of these variables with the punctuation followed immedi- ately by or e.g. are legacy forms equivalent to using the and modifiers. These forms are accepted for compatibility with make- files and POSIX but are not recommended. Four of the local vari- ables may be used in sources on dependency lines because they ex- pand to the proper value for each target on the line. These variables are and In addition, sets or knows about the following variables: The list of all targets encountered in the makefiles. If evaluated during makefile parsing, lists only those targets encountered thus far. A path to the directory where was exe- cuted. Refer to the description of for more details. Is used in error handling, see Is used in error handling, see Is used in er- ror handling, see Is used in error handling in mode, see Is used in error handling, see The directory of the file this makefile was included from. The filename of the file this makefile was included from. The machine hardware name, see The machine processor architecture name, see The name that was executed with The same as for compatibility. The preferred variable to use is the environment variable because it is more compatible with other make variants and cannot be confused with the special target with the same name. Names the makefile (default from which generated dependencies are read. If set to do not print error information at the end. A boolean that controls the default behavior of the option. If true, variable values printed with are fully ex- panded; if false, the raw variable contents (which may include additional unexpanded variable references) are shown. The list of variables exported by The top-level makefile that is currently read, as given in the command line. The environment variable may contain anything that may be specified on command line. Anything specified on command line is appended to the variable, which is then added to the environment for all programs that executes. The numeric group ID of the user running It is read-only. If is run with the output for each target is prefixed with a token the first part of which can be controlled via If is empty, no token is printed. For example, setting to would produce tokens like making it easier to track the degree of parallelism being achieved. The argument to the option. A read-only boolean that indicates whether the option supports use of The recursion depth of The top-level instance of has level 0, and each child make has its parent level plus 1. This allows tests like: to protect things which should only be evaluated in the top-level instance of The name of the environment variable that stores the level of nested calls to The ordered list of makefile names (default that looks for. The list of makefiles read by which is useful for tracking dependencies. Each makefile is recorded only once, re- gardless of the number of times read. In mode, provides a list of prefixes which match the directories controlled by If a file that was generated outside of but within said bailiwick is miss- ing, the current target is considered out-of-date. In mode, it can (very rarely!) be useful to filter command lines before com- parison. 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. In mode, this variable contains a list of all the meta files updated. If not empty, it can be used to trigger process- ing of In 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. Provides a list of variable modifiers to apply to each pathname. Ignore if the expansion is an empty string. Provides a list of path pre- fixes that should be ignored; because the contents are expected to change over time. The default list includes: Provides a list of patterns to match against pathnames. Ignore any that match. Defines the message printed for each meta file updated in mode. The default value is: Processed after reading all makefiles. Af- fects the mode that runs in. It can contain these keywords: Like puts into mode. Puts into mode, where meta files are created for each target to capture the command run, the output generated, and if is available, the system calls which are of interest to The captured output can be useful when diagnosing errors. By de- fault, does not create files in This can be overridden by setting to a value which represents true. If is true, a missing file makes the target out-of-date. If is true, missing filemon data makes the target out-of-date. Do not use For debugging, it can be useful to include the environment in the file. If in 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 Some makefiles have commands which are simply not stable. This keyword causes them to be ignored for determin- ing whether a target is out of date in mode. See also If is true, when a .meta file is created, mark the target In both com- pat and parallel mode, do not make the targets in the usual or- der, but instead randomize their order. This mode can be used to detect undeclared dependencies between files. Used to create files in a separate directory, see Used to force a separate di- rectory for the created files, even if that directory is not writable, see Used to create files in a separate directory, see The name of the operating system, see It is read-only. 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 behavior can be disabled by assigning an empty value to within a makefile. Extra variables can be exported from a makefile by ap- pending their names to is re-exported whenever is modified. If was built with support, this is set to the path of the device node. This allows makefiles to test for this support. The process ID of It is read-only. The parent process ID of It is read-only. When stops due to an error, it sets to the name of the target that failed, to the exit status of the failed target, to the commands of the failed target, and in mode, it also sets to the and to the path of the meta file (if any) describing the failed target. It then prints its name and the value of as well as the value of any variables named in If true, are preserved when doing assignments. The default is false, for backwards com- patibility. Set to true for compatability with other makes. If set to false, becomes per normal evaluation rules. If set to ap- parent variable assignments in dependency lines are treated as normal sources. The numeric ID of the user running It is read- only. This variable is simply assigned a newline character as its value. It is read-only. This allows expansions using the modifier to put a newline between iterations of the loop rather than a space. For example, in case of an error, prints the vari- able names and their values using: A path to the directory where the targets are built. Its value is determined by trying to to the following directories in order and using the first match: (Only if is set in the environment or on the command line.) (Only if is set in the environment or on the command line.) Variable expansion is performed on the value before it is used, so expressions such as may be used. This is especially useful with may be modified in the makefile via the special target In all cases, changes to the specified directory if it exists, and sets and to that directory before executing any targets. Except in the case of an explicit target, checks that the specified di- rectory is writable and ignores it if not. This check can be skipped by setting the environment variable to The directory name of the current makefile being parsed. The basename of the cur- rent makefile being parsed. This variable and are both set only while the makefiles are being parsed. To retain their current values, assign them to a variable using assignment with expansion The space-separated list of directories that searches for files. To update this search list, use the special target rather than modifying the variable directly. Is set in POSIX mode, see the special target. Alternate path to the current directory. nor- mally sets to the canonical path given by However, if the envi- ronment variable is set and gives a path to the current direc- tory, sets to the value of instead. This behavior is disabled if is set or contains a variable transform. is set to the value of for all programs which executes. The pathname of the shell used to run target scripts. It is read-only. The list of known suf- fixes. It is read-only. The space-separated list of directories that searches for makefiles, referred to as the system include path. To update this search list, use the special target rather than modifying the variable which is read-only. The list of tar- gets explicitly specified on the command line, if any. The colon-separated list of directories that searches for files. This variable is supported for compatibility with old make pro- grams only, use instead. The general format of a variable expan- sion is: Each modifier begins with a colon. To escape a colon, precede it with a backslash A list of indirect modifiers can be specified via a variable, as follows: In this case, the first modifier in the does not start with a colon, since that colon already occurs in the referencing vari- able. If any of the modifiers in the contains a dollar sign these must be doubled to avoid early expansion. 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 us- ing double quotes, single quotes and backslashes, like in the shell. The quotes and backslashes are retained in the words. The supported modifiers are: Replaces each word with its suffix. Replaces each word with its dirname. Selects only those words that match 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, the construct removes all leading and trailing whitespace and normalizes the inter-word spacing to a single space. This is the opposite of selecting all words which do match Orders the words lexicographically. Orders the words nu- merically. A number followed by one of or is multiplied by the appropriate factor, which is 1024 for 1048576 for or 1073741824 for Both upper- and lower-case letters are accepted. Orders the words in reverse lexicographical order. Orders the words in re- verse numerical order. Shuffles the words. The results are dif- ferent each time you are referring to the modified variable; use the assignment with expansion to prevent such behavior. For ex- ample, LIST= uno due tre quattro RAN- DOM_LIST= ${LIST:Ox} STATIC_RAN- DOM_LIST:= ${LIST:Ox} all: @echo "${RANDOM_LIST}" @echo "${RAN- DOM_LIST}" @echo "${STATIC_RANDOM_LIST}" @echo "${STATIC_RANDOM_LIST}" may produce output similar to: quattro due tre uno tre due quattro uno due uno quattro tre due uno quat- tro tre Quotes every shell meta-character in the value, so that it can be passed safely to the shell. Quotes every shell meta- character in the value, and also doubles characters so that it can be passed safely through recursive invocations of This is equivalent to Replaces each word with everything but its suffix. The value is an integer sequence representing the words of the original value, or the supplied The value is interpreted as a format string for using producing the formatted timestamp. Note: the format should only be used with If a value is not provided or is 0, the current time is used. Computes a 32-bit hash of the value and encodes it as 8 hex digits. The value is interpreted as a format string for using producing the formatted timestamp. If a value is not provided or is 0, the current time is used. Call with each word as pathname; use as the new value. If fails; use or current time. If is set to then failure will cause an er- ror. Attempts to convert the value to an absolute path using If that fails, the value is unchanged. Converts the value to lower- case letters. 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 If is omitted, no separator is used. The common escapes (including octal numeric codes) work as expected. Converts the value to up- per-case letters. Causes subsequent modifiers to treat the value as a single word (possibly containing embedded whitespace). See also Causes the value to be treated as a list of words. See also Modifies the first occurrence of in each word of the value, re- placing it with If a is appended to the last delimiter of the pattern, all occurrences in each word are replaced. If a is ap- pended to the last delimiter of the pattern, only the first oc- currence is affected. If a is appended to the last delimiter of the pattern, the value is treated as a single word. If begins with a caret is anchored at the beginning of each word. If ends with a dollar sign it is anchored at the end of each word. In- side an ampersand is replaced by (without the anchoring or Any character may be used as the delimiter for the parts of the modi- fier string. The anchoring, ampersand and delimiter characters can be escaped with a backslash Both and may contain nested ex- pressions. To prevent a dollar sign from starting a nested ex- pression, escape it with a backslash. The modifier works like the modifier except that the old and new strings, instead of be- ing simple strings, are an extended regular expression (see and an Normally, the first occurrence of the pattern in each word of the value is substituted with The modifier causes the substitu- tion to apply to at most one word; the modifier causes the sub- stitution to apply to as many instances of the search pattern as occur in the word or words it is found in; the modifier causes the value to be treated as a single word (possibly containing em- bedded whitespace). As for the modifier, the and are subjected to variable expansion before being parsed as regular expressions. Replaces each word with its last path component (basename). Re- moves adjacent duplicate words (like If the variable name (not its value), when parsed as a conditional expression, evaluates to true, return as its value the otherwise return the Since the variable name is used as the expression, :? must be the first modifier after the variable name which, of course, usually con- tains variable expansions. A common error is trying to use ex- pressions like which actually tests defined(NUMBERS). To deter- mine if any words match you need to use something like: This is the style substitution. It can only be the last modifier speci- fied, as a in either or is treated as a regular character, not as the end of the modifier. If does not contain the pattern match- ing character and the word ends with or equals it, that suffix is replaced with Otherwise, the first in matches a possibly empty substring of arbitrary characters, and if the whole pattern is found in the word, the matching part is replaced with and the first occurrence of in (if any) is replaced with the substring matched by the Both and may contain nested expressions. To pre- vent a dollar sign from starting a nested expression, escape it with a backslash. This is the loop expansion mechanism from the OSF Development Environment (ODE) make. Unlike loops, expansion occurs at the time of reference. For each word in the value, as- sign the word to the variable named and evaluate The ODE conven- tion is that should start and end with a period, for example: However, a single-letter variable is often more readable: Saves the current variable value in or the named for later reference. Example usage: M_cmpv.units = 1 1000 1000000 M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \ \* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh Here is used to save the result of the modifier which is later referenced using the index values from If the variable is unde- fined, the optional (which may be empty) is the value. If the variable is defined, the existing value is returned. This is an- other 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: If the variable is defined, (which may be empty) is the value. The name of the variable is the value. 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. The output of running is the value. The value is run as a command, and the output becomes the new value. The variable is assigned the value after substitution. This modifier and its variations are useful in obscure situations such as want- ing to set a variable at a point where a target's shell commands are being parsed. These assignment modifiers always expand to nothing. The helps avoid false matches with the style modifier and since substitution always occurs, the form is vaguely appro- priate. As for but only if the variable does not already have a value. Append to the variable. Assign the output of to the variable. Selects one or more words from the value, or performs other operations related to the way in which the value is split into words. 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 is subjected to variable expansion, and the expanded result is then interpreted as follows: Selects a single word from the value. Selects all words from to inclusive. For example, selects all words from the second word to the last word. If is greater than the words are output in reverse order. For example, selects all the words from last to first. If the list is already ordered, this effectively reverses the list, but it is more effi- cient to use instead of Causes subsequent modifiers to treat the value as a single word (possibly containing embedded whitespace). Analogous to the effect of in Bourne shell. Means the same as Causes subsequent modifiers to treat the value as a sequence of words delimited by whitespace. Analogous to the effect of in Bourne shell. Returns the number of words in the value. offers directives for including makefiles, conditionals and for loops. All these directives are identified by a line beginning with a single dot character, followed by the keyword of the directive, such as or Files are included with either or Variables between the angle brackets or double quotes are expanded to form the file name. If angle brackets are used, the included makefile is ex- pected to be in the system makefile directory. If double quotes are used, the including makefile's directory and any directories specified using the option are searched before the system make- file directory. For compatibility with other make variants, (without leading dot) is also accepted. If the include statement is written as or as errors locating and/or opening include files are ignored. If the include statement is written as not only are errors locating and/or opening include files ignored, but stale dependencies within the included file are ignored just like in The directives for exporting and unexporting variables are: Ex- port the specified global variable. If no variable list is pro- vided, all globals are exported except for internal variables (those that start with This is not affected by the flag, so should be used with caution. For compatibility with other make programs, (without leading dot) is also accepted. Appending a variable name to is equivalent to exporting a variable. The same as except that the variable is not appended to This allows ex- porting a value to the environment which is different from that used by internally. The same as except that variables in the value are not expanded. The opposite of The specified global is removed from If no variable list is provided, all globals are un- exported, and deleted. Unexport all globals previously exported and clear the environment inherited from the parent. This opera- tion causes a memory leak of the original environment, so should be used sparingly. Testing for being 0 would make sense. Also note that any variables which originated in the parent environ- ment should be explicitly preserved if desired. For example: PATH := ${PATH} Would result in an environment containing only which is the minimal useful environment. Actually is also pushed into the new environment. The directives for printing messages to the output are: The message is printed along with the name of the makefile and line number. The message prefixed by is printed along with the name of the makefile and line number. The message is printed along with the name of the makefile and line number, exits immediately. The directives for conditionals are: Test the value of an expression. Test whether a variable is defined. Test whether a variable is not defined. Test the target being requested. Test the target being requested. Reverse the sense of the last conditional. A combination of followed by A combina- tion of followed by A combination of followed by A combination of followed by A combination of followed by End the body of the con- ditional. The may be any one of the following: Logical OR. Log- ical AND; of higher precedence than only evaluates a conditional as far as is necessary to determine its value. Parentheses can be used to override the operator precedence. The boolean opera- tor may be used to logically negate an expression, typically a function call. It is of higher precedence than The value of may be any of the following function call expressions: Evaluates to true if the variable has been defined. Evaluates to true if the target was specified as part of command line or was declared the default target (either implicitly or explicitly, see before the line containing the conditional. Evaluates to true if the expan- sion of the variable, after applying the modifiers, results in an empty string. Evaluates to true if the given pathname exists. If relative, the pathname is searched for on the system search path (see Evaluates to true if the target has been defined. Evaluates to true if the target has been defined and has commands associated with it. may also be an arithmetic or string compari- son. Variable expansion is performed on both sides of the com- parison. If both sides are numeric and neither is enclosed in quotes, the comparison is done numerically, otherwise lexico- graphically. A string is interpreted as a hexadecimal integer if it is preceded by otherwise it is interpreted as a decimal float- ing-point number; octal numbers are not supported. All compar- isons may use the operators and Numeric comparisons may also use the operators and If the comparison has neither a comparison op- erator nor a right side, the expression evaluates to true if it is nonempty and its numeric value (if any) is not zero. When is evaluating one of these conditional expressions, and it encoun- ters a (whitespace-separated) word it doesn't recognize, either the or function is applied to it, depending on the form of the conditional. If the form is or the function is applied. Simi- larly, if the form is or the function is applied. If the condi- tional evaluates to true, parsing of the makefile continues as before. If it evaluates to false, the following lines until the corresponding variant, or are skipped. For loops are typically used to apply a set of rules to a list of files. The syntax of a for loop is: The is expanded and then split into words. On each iteration of the loop, one word is taken and assigned to each in order, and these are substituted into the 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. If is encountered within a loop, it causes early termination of the loop, otherwise a parse error. Un-define the specified global variables. Only global variables can be un-defined. Comments begin with a hash character, any- where but in a shell command line, and continue to the end of an unescaped new line. Target is never out of date, but always exe- cute commands anyway. Ignore any errors from the commands asso- ciated with this target, exactly as if they all were preceded by a dash Mark all sources of this target as being up to date. Exe- cute the commands associated with this target even if the or op- tions were specified. Normally used to mark recursive Create a meta file for the target, even if it is flagged as or Usage in conjunction with is the most likely case. In mode, the target is out-of-date if the meta file is missing. Do not create a meta file for the target. Meta files are also not created for or tar- gets. 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 ap- plies to any command line that uses the variable which can be used for that purpose even when not otherwise needed or desired: skip-compare-for-some: @echo this is compared @echo this is not ${.OODATE:M.NOMETA_CMP} @echo this is also compared The pattern suppresses any expansion of the unwanted variable. Do not search for the target in the directories specified by Nor- mally selects the first target it encounters as the default tar- get to be built if no target was specified. This source prevents this target from being selected. If a target is marked with this attribute and can't figure out how to create it, it ignores this fact and assumes the file isn't needed or already exists. The target does not correspond to an actual file; it is always con- sidered to be out of date, and is not created with the option. Suffix-transformation rules are not applied to targets. When is interrupted, it normally removes any partially made targets. This source prevents the target from being removed. Synonym for Do not echo any of the commands associated with this target, ex- actly as if they all were preceded by an at sign Turn the target into 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 of the source. If the target already has commands, the target's commands are appended to them. Like but instead of appending, prepend the target commands to the tar- get. If 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 the output is always The ordering imposed by is only relevant for parallel makes. Special targets may not be included with other targets, i.e. they must be the only target specified. Any com- mand lines attached to this target are executed before anything else is done. This is sort of a rule for any target (that was used only as a source) that can't figure out any other way to create. Only the shell script is used. The variable of a target that inherits commands is set to the target's own name. 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. Any command lines at- tached to this target are executed after everything else is done successfully. Any command lines attached to this target are exe- cuted when another target fails. See for the variables that will be set. Mark each of the sources with the attribute. If no sources are specified, this is the equivalent of specifying the option. If is interrupted, the commands for this target are exe- cuted. If no target is specified when is invoked, this target is built. This target provides a way to specify flags for at the time when the makefiles are read. The flags are as if typed to the shell, though the option has no effect. Apply the attribute to any specified sources. Disable parallel mode. Synonym for for compatibility with other pmake variants. clear the read-only attribute from the global variables specified as sources. The source is a new value for If it exists, changes the current work- ing directory to it and updates the value of In parallel mode, the named targets are made in sequence. This ordering does not add targets to the list of targets to be made. Since the depen- dents of a target do not get built until the target itself could be built, unless is built by another part of the dependency graph, the following is a dependency loop: .ORDER: b a b: a 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 target, the current working directory is searched last. Like but applies only to files with a particular suffix. The suffix must have been previously de- clared with Apply the attribute to any specified sources. If this is the first non-comment line in the main makefile, the variable is set to the value and the makefile is included if it exists, to provide POSIX-compatible default rules. If is run with the flag, only contributes to the default rules. Apply the attribute to any specified sources. If no sources are specified, the attribute is applied to every target in the file. set the read-only attribute on the global variables specified as sources. Sets the shell that uses to execute commands. The sources are a set of pairs. This is the minimal specification, used to select one of the built-in shell specs; and Specifies the absolute path to the shell. Indicates whether the shell supports exit on er- ror. The command to turn on error checking. The command to dis- able error checking. The command to turn on echoing of commands executed. The command to turn off echoing of commands executed. The output to filter after issuing the command. It is typically identical to The flag to pass the shell to enable error checking. The flag to pass the shell to enable command echoing. The string literal to pass the shell that results in a single newline char- acter when used outside of any quoting characters. Example: .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'" Apply the attribute to any specified sources. If no sources are specified, the attribute is applied to every com- mand in the file. This target gets run when a dependency file contains stale entries, having set to the name of that dependency file. Each source specifies a suffix to If no sources are speci- fied, any previously specified suffixes are deleted. It allows the creation of suffix-transformation rules. Example: .SUFFIXES: .c .o .c.o: cc -o ${.TARGET} -c ${.IMPSRC} The sources are directories which are to be added to the system include path which searches for makefiles. If no sources are specified, any previously specified directories are removed from the system in- clude path. uses the following environment variables, if they exist: and and may only be set in the environment or on the com- mand line to and not as makefile variables; see the description of for more details. list of dependencies first default makefile if no makefile is specified on the command line second default makefile if no makefile is specified on the command line system makefile system makefile directory The basic make syntax is com- patible between different make variants; however the special variables, variable modifiers and conditionals are not. An in- complete list of changes in older versions of 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. 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. Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not support most of the features of as described in this manual. Most notably: The and declarations and most functionality pertaining to paralleliza- tion. (GNU make supports parallelization but lacks the features needed to control it effectively.) 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.) All built-in variables that begin with a dot. Most of the special sources and targets that begin with a dot, with the notable exception of and Variable modifiers, except for the string substitution, which does not portably support globbing with and historically only works on declared suffixes. The vari- able even in its short form; most makes support this functional- ity but its name varies. Some features are somewhat more portable, such as assignment with and The functionality is based on an older feature found in GNU make and many versions of SVR4 make; however, historically its behavior is too ill-defined (and too buggy) to rely upon. The and variables are more or less uni- versally portable, as is the variable. Basic use of suffix rules (for files only in the current directory, not trying to chain transformations together, etc.) is also reasonably portable. is derived from NetBSD It uses autoconf to facilitate portability to other platforms. A make command appeared in This make implemen- tation is based on Adam de Boor's pmake program, which was writ- ten for Sprite at Berkeley. It was designed to be a parallel distributed make running jobs on different machines using a dae- mon called Historically the target/dependency has been used to FoRCe rebuilding (since the target/dependency does not exist ... unless someone creates an file). The make 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 termi- nator 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. In jobs mode, when a target fails; make will put an error token into the job token pool. This will cause all other instances of make using that token pool to abort the build and exit with error code 6. Sometimes the attempt to suppress a cascade of unnecessary er- rors, can result in a seemingly unexplained