1.\" $NetBSD: make.1,v 1.271 2017/07/03 21:34:20 wiz Exp $ 2.\" 3.\" Copyright (c) 1990, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" from: @(#)make.1 8.4 (Berkeley) 3/19/94 31.\" 32.Dd June 22, 2017 33.Dt MAKE 1 34.Os 35.Sh NAME 36.Nm make 37.Nd maintain program dependencies 38.Sh SYNOPSIS 39.Nm 40.Op Fl BeikNnqrstWwX 41.Op Fl C Ar directory 42.Op Fl D Ar variable 43.Op Fl d Ar flags 44.Op Fl f Ar makefile 45.Op Fl I Ar directory 46.Op Fl J Ar private 47.Op Fl j Ar max_jobs 48.Op Fl m Ar directory 49.Op Fl T Ar file 50.Op Fl V Ar variable 51.Op Fl v Ar variable 52.Op Ar variable=value 53.Op Ar target ... 54.Sh DESCRIPTION 55.Nm 56is a program designed to simplify the maintenance of other programs. 57Its input is a list of specifications as to the files upon which programs 58and other files depend. 59If no 60.Fl f Ar makefile 61makefile option is given, 62.Nm 63will try to open 64.Ql Pa makefile 65then 66.Ql Pa Makefile 67in order to find the specifications. 68If the file 69.Ql Pa .depend 70exists, it is read (see 71.Xr mkdep 1 ) . 72.Pp 73This manual page is intended as a reference document only. 74For a more thorough description of 75.Nm 76and makefiles, please refer to 77.%T "PMake \- A Tutorial" . 78.Pp 79.Nm 80will prepend the contents of the 81.Va MAKEFLAGS 82environment variable to the command line arguments before parsing them. 83.Pp 84The options are as follows: 85.Bl -tag -width Ds 86.It Fl B 87Try to be backwards compatible by executing a single shell per command and 88by executing the commands to make the sources of a dependency line in sequence. 89.It Fl C Ar directory 90Change to 91.Ar directory 92before reading the makefiles or doing anything else. 93If multiple 94.Fl C 95options are specified, each is interpreted relative to the previous one: 96.Fl C Pa / Fl C Pa etc 97is equivalent to 98.Fl C Pa /etc . 99.It Fl D Ar variable 100Define 101.Ar variable 102to be 1, in the global context. 103.It Fl d Ar [-]flags 104Turn on debugging, and specify which portions of 105.Nm 106are to print debugging information. 107Unless the flags are preceded by 108.Ql \- 109they are added to the 110.Va MAKEFLAGS 111environment variable and will be processed by any child make processes. 112By default, debugging information is printed to standard error, 113but this can be changed using the 114.Ar F 115debugging flag. 116The debugging output is always unbuffered; in addition, if debugging 117is enabled but debugging output is not directed to standard output, 118then the standard output is line buffered. 119.Ar Flags 120is one or more of the following: 121.Bl -tag -width Ds 122.It Ar A 123Print all possible debugging information; 124equivalent to specifying all of the debugging flags. 125.It Ar a 126Print debugging information about archive searching and caching. 127.It Ar C 128Print debugging information about current working directory. 129.It Ar c 130Print debugging information about conditional evaluation. 131.It Ar d 132Print debugging information about directory searching and caching. 133.It Ar e 134Print debugging information about failed commands and targets. 135.It Ar F Ns Oo Sy \&+ Oc Ns Ar filename 136Specify where debugging output is written. 137This must be the last flag, because it consumes the remainder of 138the argument. 139If the character immediately after the 140.Ql F 141flag is 142.Ql \&+ , 143then the file will be opened in append mode; 144otherwise the file will be overwritten. 145If the file name is 146.Ql stdout 147or 148.Ql stderr 149then debugging output will be written to the 150standard output or standard error output file descriptors respectively 151(and the 152.Ql \&+ 153option has no effect). 154Otherwise, the output will be written to the named file. 155If the file name ends 156.Ql .%d 157then the 158.Ql %d 159is replaced by the pid. 160.It Ar f 161Print debugging information about loop evaluation. 162.It Ar "g1" 163Print the input graph before making anything. 164.It Ar "g2" 165Print the input graph after making everything, or before exiting 166on error. 167.It Ar "g3" 168Print the input graph before exiting on error. 169.It Ar j 170Print debugging information about running multiple shells. 171.It Ar l 172Print commands in Makefiles regardless of whether or not they are prefixed by 173.Ql @ 174or other "quiet" flags. 175Also known as "loud" behavior. 176.It Ar M 177Print debugging information about "meta" mode decisions about targets. 178.It Ar m 179Print debugging information about making targets, including modification 180dates. 181.It Ar n 182Don't delete the temporary command scripts created when running commands. 183These temporary scripts are created in the directory 184referred to by the 185.Ev TMPDIR 186environment variable, or in 187.Pa /tmp 188if 189.Ev TMPDIR 190is unset or set to the empty string. 191The temporary scripts are created by 192.Xr mkstemp 3 , 193and have names of the form 194.Pa makeXXXXXX . 195.Em NOTE : 196This can create many files in 197.Ev TMPDIR 198or 199.Pa /tmp , 200so use with care. 201.It Ar p 202Print debugging information about makefile parsing. 203.It Ar s 204Print debugging information about suffix-transformation rules. 205.It Ar t 206Print debugging information about target list maintenance. 207.It Ar V 208Force the 209.Fl V 210option to print raw values of variables, overriding the default behavior 211set via 212.Va .MAKE.EXPAND_VARIABLES . 213.It Ar v 214Print debugging information about variable assignment. 215.It Ar x 216Run shell commands with 217.Fl x 218so the actual commands are printed as they are executed. 219.El 220.It Fl e 221Specify that environment variables override macro assignments within 222makefiles. 223.It Fl f Ar makefile 224Specify a makefile to read instead of the default 225.Ql Pa makefile . 226If 227.Ar makefile 228is 229.Ql Fl , 230standard input is read. 231Multiple makefiles may be specified, and are read in the order specified. 232.It Fl I Ar directory 233Specify a directory in which to search for makefiles and included makefiles. 234The system makefile directory (or directories, see the 235.Fl m 236option) is automatically included as part of this list. 237.It Fl i 238Ignore non-zero exit of shell commands in the makefile. 239Equivalent to specifying 240.Ql Fl 241before each command line in the makefile. 242.It Fl J Ar private 243This option should 244.Em not 245be specified by the user. 246.Pp 247When the 248.Ar j 249option is in use in a recursive build, this option is passed by a make 250to child makes to allow all the make processes in the build to 251cooperate to avoid overloading the system. 252.It Fl j Ar max_jobs 253Specify the maximum number of jobs that 254.Nm 255may have running at any one time. 256The value is saved in 257.Va .MAKE.JOBS . 258Turns compatibility mode off, unless the 259.Ar B 260flag is also specified. 261When compatibility mode is off, all commands associated with a 262target are executed in a single shell invocation as opposed to the 263traditional one shell invocation per line. 264This can break traditional scripts which change directories on each 265command invocation and then expect to start with a fresh environment 266on the next line. 267It is more efficient to correct the scripts rather than turn backwards 268compatibility on. 269.It Fl k 270Continue processing after errors are encountered, but only on those targets 271that do not depend on the target whose creation caused the error. 272.It Fl m Ar directory 273Specify a directory in which to search for sys.mk and makefiles included 274via the 275.Ao Ar file Ac Ns -style 276include statement. 277The 278.Fl m 279option can be used multiple times to form a search path. 280This path will override the default system include path: /usr/share/mk. 281Furthermore the system include path will be appended to the search path used 282for 283.Qo Ar file Qc Ns -style 284include statements (see the 285.Fl I 286option). 287.Pp 288If a file or directory name in the 289.Fl m 290argument (or the 291.Ev MAKESYSPATH 292environment variable) starts with the string 293.Qq \&.../ 294then 295.Nm 296will search for the specified file or directory named in the remaining part 297of the argument string. 298The search starts with the current directory of 299the Makefile and then works upward towards the root of the file system. 300If the search is successful, then the resulting directory replaces the 301.Qq \&.../ 302specification in the 303.Fl m 304argument. 305If used, this feature allows 306.Nm 307to easily search in the current source tree for customized sys.mk files 308(e.g., by using 309.Qq \&.../mk/sys.mk 310as an argument). 311.It Fl n 312Display the commands that would have been executed, but do not 313actually execute them unless the target depends on the .MAKE special 314source (see below). 315.It Fl N 316Display the commands which would have been executed, but do not 317actually execute any of them; useful for debugging top-level makefiles 318without descending into subdirectories. 319.It Fl q 320Do not execute any commands, but exit 0 if the specified targets are 321up-to-date and 1, otherwise. 322.It Fl r 323Do not use the built-in rules specified in the system makefile. 324.It Fl s 325Do not echo any commands as they are executed. 326Equivalent to specifying 327.Ql Ic @ 328before each command line in the makefile. 329.It Fl T Ar tracefile 330When used with the 331.Fl j 332flag, 333append a trace record to 334.Ar tracefile 335for each job started and completed. 336.It Fl t 337Rather than re-building a target as specified in the makefile, create it 338or update its modification time to make it appear up-to-date. 339.It Fl V Ar variable 340Print the value of 341.Ar variable . 342Do not build any targets. 343Multiple instances of this option may be specified; 344the variables will be printed one per line, 345with a blank line for each null or undefined variable. 346The value printed is extracted from the global context after all 347makefiles have been read. 348By default, the raw variable contents (which may 349include additional unexpanded variable references) are shown. 350If 351.Ar variable 352contains a 353.Ql \&$ 354then the value will be recursively expanded to its complete resultant 355text before printing. 356The expanded value will also be printed if 357.Va .MAKE.EXPAND_VARIABLES 358is set to true and 359the 360.Fl dV 361option has not been used to override it. 362Note that loop-local and target-local variables, as well as values 363taken temporarily by global variables during makefile processing, are 364not accessible via this option. 365The 366.Fl dv 367debug mode can be used to see these at the cost of generating 368substantial extraneous output. 369.It Fl v Ar variable 370Like 371.Fl V 372but the variable is always expanded to its complete value. 373.It Fl W 374Treat any warnings during makefile parsing as errors. 375.It Fl w 376Print entering and leaving directory messages, pre and post processing. 377.It Fl X 378Don't export variables passed on the command line to the environment 379individually. 380Variables passed on the command line are still exported 381via the 382.Va MAKEFLAGS 383environment variable. 384This option may be useful on systems which have a small limit on the 385size of command arguments. 386.It Ar variable=value 387Set the value of the variable 388.Ar variable 389to 390.Ar value . 391Normally, all values passed on the command line are also exported to 392sub-makes in the environment. 393The 394.Fl X 395flag disables this behavior. 396Variable assignments should follow options for POSIX compatibility 397but no ordering is enforced. 398.El 399.Pp 400There are seven different types of lines in a makefile: file dependency 401specifications, shell commands, variable assignments, include statements, 402conditional directives, for loops, and comments. 403.Pp 404In general, lines may be continued from one line to the next by ending 405them with a backslash 406.Pq Ql \e . 407The trailing newline character and initial whitespace on the following 408line are compressed into a single space. 409.Sh FILE DEPENDENCY SPECIFICATIONS 410Dependency lines consist of one or more targets, an operator, and zero 411or more sources. 412This creates a relationship where the targets 413.Dq depend 414on the sources 415and are usually created from them. 416The exact relationship between the target and the source is determined 417by the operator that separates them. 418The three operators are as follows: 419.Bl -tag -width flag 420.It Ic \&: 421A target is considered out-of-date if its modification time is less than 422those of any of its sources. 423Sources for a target accumulate over dependency lines when this operator 424is used. 425The target is removed if 426.Nm 427is interrupted. 428.It Ic \&! 429Targets are always re-created, but not until all sources have been 430examined and re-created as necessary. 431Sources for a target accumulate over dependency lines when this operator 432is used. 433The target is removed if 434.Nm 435is interrupted. 436.It Ic \&:: 437If no sources are specified, the target is always re-created. 438Otherwise, a target is considered out-of-date if any of its sources has 439been modified more recently than the target. 440Sources for a target do not accumulate over dependency lines when this 441operator is used. 442The target will not be removed if 443.Nm 444is interrupted. 445.El 446.Pp 447Targets and sources may contain the shell wildcard values 448.Ql \&? , 449.Ql * , 450.Ql [] , 451and 452.Ql {} . 453The values 454.Ql \&? , 455.Ql * , 456and 457.Ql [] 458may only be used as part of the final 459component of the target or source, and must be used to describe existing 460files. 461The value 462.Ql {} 463need not necessarily be used to describe existing files. 464Expansion is in directory order, not alphabetically as done in the shell. 465.Sh SHELL COMMANDS 466Each target may have associated with it one or more lines of shell 467commands, normally 468used to create the target. 469Each of the lines in this script 470.Em must 471be preceded by a tab. 472(For historical reasons, spaces are not accepted.) 473While targets can appear in many dependency lines if desired, by 474default only one of these rules may be followed by a creation 475script. 476If the 477.Ql Ic \&:: 478operator is used, however, all rules may include scripts and the 479scripts are executed in the order found. 480.Pp 481Each line is treated as a separate shell command, unless the end of 482line is escaped with a backslash 483.Pq Ql \e 484in which case that line and the next are combined. 485.\" The escaped newline is retained and passed to the shell, which 486.\" normally ignores it. 487.\" However, the tab at the beginning of the following line is removed. 488If the first characters of the command are any combination of 489.Ql Ic @ , 490.Ql Ic + , 491or 492.Ql Ic \- , 493the command is treated specially. 494A 495.Ql Ic @ 496causes the command not to be echoed before it is executed. 497A 498.Ql Ic + 499causes the command to be executed even when 500.Fl n 501is given. 502This is similar to the effect of the .MAKE special source, 503except that the effect can be limited to a single line of a script. 504A 505.Ql Ic \- 506in compatibility mode 507causes any non-zero exit status of the command line to be ignored. 508.Pp 509When 510.Nm 511is run in jobs mode with 512.Fl j Ar max_jobs , 513the entire script for the target is fed to a 514single instance of the shell. 515In compatibility (non-jobs) mode, each command is run in a separate process. 516If the command contains any shell meta characters 517.Pq Ql #=|^(){};&<>*?[]:$`\e\en 518it will be passed to the shell; otherwise 519.Nm 520will attempt direct execution. 521If a line starts with 522.Ql Ic \- 523and the shell has ErrCtl enabled then failure of the command line 524will be ignored as in compatibility mode. 525Otherwise 526.Ql Ic \- 527affects the entire job; 528the script will stop at the first command line that fails, 529but the target will not be deemed to have failed. 530.Pp 531Makefiles should be written so that the mode of 532.Nm 533operation does not change their behavior. 534For example, any command which needs to use 535.Dq cd 536or 537.Dq chdir 538without potentially changing the directory for subsequent commands 539should be put in parentheses so it executes in a subshell. 540To force the use of one shell, escape the line breaks so as to make 541the whole script one command. 542For example: 543.Bd -literal -offset indent 544avoid-chdir-side-effects: 545 @echo Building $@ in `pwd` 546 @(cd ${.CURDIR} && ${MAKE} $@) 547 @echo Back in `pwd` 548 549ensure-one-shell-regardless-of-mode: 550 @echo Building $@ in `pwd`; \e 551 (cd ${.CURDIR} && ${MAKE} $@); \e 552 echo Back in `pwd` 553.Ed 554.Pp 555Since 556.Nm 557will 558.Xr chdir 2 559to 560.Ql Va .OBJDIR 561before executing any targets, each child process 562starts with that as its current working directory. 563.Sh VARIABLE ASSIGNMENTS 564Variables in make are much like variables in the shell, and, by tradition, 565consist of all upper-case letters. 566.Ss Variable assignment modifiers 567The five operators that can be used to assign values to variables are as 568follows: 569.Bl -tag -width Ds 570.It Ic \&= 571Assign the value to the variable. 572Any previous value is overridden. 573.It Ic \&+= 574Append the value to the current value of the variable. 575.It Ic \&?= 576Assign the value to the variable if it is not already defined. 577.It Ic \&:= 578Assign with expansion, i.e. expand the value before assigning it 579to the variable. 580Normally, expansion is not done until the variable is referenced. 581.Em NOTE : 582References to undefined variables are 583.Em not 584expanded. 585This can cause problems when variable modifiers are used. 586.It Ic \&!= 587Expand the value and pass it to the shell for execution and assign 588the result to the variable. 589Any newlines in the result are replaced with spaces. 590.El 591.Pp 592Any white-space before the assigned 593.Ar value 594is removed; if the value is being appended, a single space is inserted 595between the previous contents of the variable and the appended value. 596.Pp 597Variables are expanded by surrounding the variable name with either 598curly braces 599.Pq Ql {} 600or parentheses 601.Pq Ql () 602and preceding it with 603a dollar sign 604.Pq Ql \&$ . 605If the variable name contains only a single letter, the surrounding 606braces or parentheses are not required. 607This shorter form is not recommended. 608.Pp 609If the variable name contains a dollar, then the name itself is expanded first. 610This allows almost arbitrary variable names, however names containing dollar, 611braces, parenthesis, or whitespace are really best avoided! 612.Pp 613If the result of expanding a variable contains a dollar sign 614.Pq Ql \&$ 615the string is expanded again. 616.Pp 617Variable substitution occurs at three distinct times, depending on where 618the variable is being used. 619.Bl -enum 620.It 621Variables in dependency lines are expanded as the line is read. 622.It 623Variables in shell commands are expanded when the shell command is 624executed. 625.It 626.Dq .for 627loop index variables are expanded on each loop iteration. 628Note that other variables are not expanded inside loops so 629the following example code: 630.Bd -literal -offset indent 631 632.Dv .for i in 1 2 3 633a+= ${i} 634j= ${i} 635b+= ${j} 636.Dv .endfor 637 638all: 639 @echo ${a} 640 @echo ${b} 641 642.Ed 643will print: 644.Bd -literal -offset indent 6451 2 3 6463 3 3 647 648.Ed 649Because while ${a} contains 650.Dq 1 2 3 651after the loop is executed, ${b} 652contains 653.Dq ${j} ${j} ${j} 654which expands to 655.Dq 3 3 3 656since after the loop completes ${j} contains 657.Dq 3 . 658.El 659.Ss Variable classes 660The four different classes of variables (in order of increasing precedence) 661are: 662.Bl -tag -width Ds 663.It Environment variables 664Variables defined as part of 665.Nm Ns 's 666environment. 667.It Global variables 668Variables defined in the makefile or in included makefiles. 669.It Command line variables 670Variables defined as part of the command line. 671.It Local variables 672Variables that are defined specific to a certain target. 673.El 674.Pp 675Local variables are all built in and their values vary magically from 676target to target. 677It is not currently possible to define new local variables. 678The seven local variables are as follows: 679.Bl -tag -width ".ARCHIVE" -offset indent 680.It Va .ALLSRC 681The list of all sources for this target; also known as 682.Ql Va \&> . 683.It Va .ARCHIVE 684The name of the archive file; also known as 685.Ql Va \&! . 686.It Va .IMPSRC 687In suffix-transformation rules, the name/path of the source from which the 688target is to be transformed (the 689.Dq implied 690source); also known as 691.Ql Va \&< . 692It is not defined in explicit rules. 693.It Va .MEMBER 694The name of the archive member; also known as 695.Ql Va % . 696.It Va .OODATE 697The list of sources for this target that were deemed out-of-date; also 698known as 699.Ql Va \&? . 700.It Va .PREFIX 701The file prefix of the target, containing only the file portion, no suffix 702or preceding directory components; also known as 703.Ql Va * . 704The suffix must be one of the known suffixes declared with 705.Ic .SUFFIXES 706or it will not be recognized. 707.It Va .TARGET 708The name of the target; also known as 709.Ql Va @ . 710For compatibility with other makes this is an alias for 711.Ic .ARCHIVE 712in archive member rules. 713.El 714.Pp 715The shorter forms 716.Ql ( Va > , 717.Ql Va \&! , 718.Ql Va < , 719.Ql Va % , 720.Ql Va \&? , 721.Ql Va * , 722and 723.Ql Va @ ) 724are permitted for backward 725compatibility with historical makefiles and legacy POSIX make and are 726not recommended. 727.Pp 728Variants of these variables with the punctuation followed immediately by 729.Ql D 730or 731.Ql F , 732e.g. 733.Ql Va $(@D) , 734are legacy forms equivalent to using the 735.Ql :H 736and 737.Ql :T 738modifiers. 739These forms are accepted for compatibility with 740.At V 741makefiles and POSIX but are not recommended. 742.Pp 743Four of the local variables may be used in sources on dependency lines 744because they expand to the proper value for each target on the line. 745These variables are 746.Ql Va .TARGET , 747.Ql Va .PREFIX , 748.Ql Va .ARCHIVE , 749and 750.Ql Va .MEMBER . 751.Ss Additional built-in variables 752In addition, 753.Nm 754sets or knows about the following variables: 755.Bl -tag -width .MAKEOVERRIDES 756.It Va \&$ 757A single dollar sign 758.Ql \&$ , 759i.e. 760.Ql \&$$ 761expands to a single dollar 762sign. 763.It Va .ALLTARGETS 764The list of all targets encountered in the Makefile. 765If evaluated during 766Makefile parsing, lists only those targets encountered thus far. 767.It Va .CURDIR 768A path to the directory where 769.Nm 770was executed. 771Refer to the description of 772.Ql Ev PWD 773for more details. 774.It Va .INCLUDEDFROMDIR 775The directory of the file this Makefile was included from. 776.It Va .INCLUDEDFROMFILE 777The filename of the file this Makefile was included from. 778.It Ev MAKE 779The name that 780.Nm 781was executed with 782.Pq Va argv[0] . 783For compatibility 784.Nm 785also sets 786.Va .MAKE 787with the same value. 788The preferred variable to use is the environment variable 789.Ev MAKE 790because it is more compatible with other versions of 791.Nm 792and cannot be confused with the special target with the same name. 793.It Va .MAKE.ALWAYS_PASS_JOB_QUEUE 794Tells 795.Nm 796whether to pass the descriptors of the job token queue 797even if the target is not tagged with 798.Ic .MAKE 799The default is 800.Ql Pa yes 801for backwards compatability with 802.Fx 9.0 803and earlier. 804.It Va .MAKE.DEPENDFILE 805Names the makefile (default 806.Ql Pa .depend ) 807from which generated dependencies are read. 808.It Va .MAKE.EXPAND_VARIABLES 809A boolean that controls the default behavior of the 810.Fl V 811option. 812If true, variable values printed with 813.Fl V 814are fully expanded; if false, the raw variable contents (which may 815include additional unexpanded variable references) are shown. 816.It Va .MAKE.EXPORTED 817The list of variables exported by 818.Nm . 819.It Va .MAKE.JOBS 820The argument to the 821.Fl j 822option. 823.It Va .MAKE.JOB.PREFIX 824If 825.Nm 826is run with 827.Ar j 828then output for each target is prefixed with a token 829.Ql --- target --- 830the first part of which can be controlled via 831.Va .MAKE.JOB.PREFIX . 832If 833.Va .MAKE.JOB.PREFIX 834is empty, no token is printed. 835.br 836For example: 837.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}] 838would produce tokens like 839.Ql ---make[1234] target --- 840making it easier to track the degree of parallelism being achieved. 841.It Ev MAKEFLAGS 842The environment variable 843.Ql Ev MAKEFLAGS 844may contain anything that 845may be specified on 846.Nm Ns 's 847command line. 848Anything specified on 849.Nm Ns 's 850command line is appended to the 851.Ql Ev MAKEFLAGS 852variable which is then 853entered into the environment for all programs which 854.Nm 855executes. 856.It Va .MAKE.LEVEL 857The recursion depth of 858.Nm . 859The initial instance of 860.Nm 861will be 0, and an incremented value is put into the environment 862to be seen by the next generation. 863This allows tests like: 864.Li .if ${.MAKE.LEVEL} == 0 865to protect things which should only be evaluated in the initial instance of 866.Nm . 867.It Va .MAKE.MAKEFILE_PREFERENCE 868The ordered list of makefile names 869(default 870.Ql Pa makefile , 871.Ql Pa Makefile ) 872that 873.Nm 874will look for. 875.It Va .MAKE.MAKEFILES 876The list of makefiles read by 877.Nm , 878which is useful for tracking dependencies. 879Each makefile is recorded only once, regardless of the number of times read. 880.It Va .MAKE.MODE 881Processed after reading all makefiles. 882Can affect the mode that 883.Nm 884runs in. 885It can contain a number of keywords: 886.Bl -hang -width missing-filemon=bf. 887.It Pa compat 888Like 889.Fl B , 890puts 891.Nm 892into "compat" mode. 893.It Pa meta 894Puts 895.Nm 896into "meta" mode, where meta files are created for each target 897to capture the command run, the output generated and if 898.Xr filemon 4 899is available, the system calls which are of interest to 900.Nm . 901The captured output can be very useful when diagnosing errors. 902.It Pa curdirOk= Ar bf 903Normally 904.Nm 905will not create .meta files in 906.Ql Va .CURDIR . 907This can be overridden by setting 908.Va bf 909to a value which represents True. 910.It Pa missing-meta= Ar bf 911If 912.Va bf 913is True, then a missing .meta file makes the target out-of-date. 914.It Pa missing-filemon= Ar bf 915If 916.Va bf 917is True, then missing filemon data makes the target out-of-date. 918.It Pa nofilemon 919Do not use 920.Xr filemon 4 . 921.It Pa env 922For debugging, it can be useful to include the environment 923in the .meta file. 924.It Pa verbose 925If in "meta" mode, print a clue about the target being built. 926This is useful if the build is otherwise running silently. 927The message printed the value of: 928.Va .MAKE.META.PREFIX . 929.It Pa ignore-cmd 930Some makefiles have commands which are simply not stable. 931This keyword causes them to be ignored for 932determining whether a target is out of date in "meta" mode. 933See also 934.Ic .NOMETA_CMP . 935.It Pa silent= Ar bf 936If 937.Va bf 938is True, when a .meta file is created, mark the target 939.Ic .SILENT . 940.El 941.It Va .MAKE.META.BAILIWICK 942In "meta" mode, provides a list of prefixes which 943match the directories controlled by 944.Nm . 945If a file that was generated outside of 946.Va .OBJDIR 947but within said bailiwick is missing, 948the current target is considered out-of-date. 949.It Va .MAKE.META.CREATED 950In "meta" mode, this variable contains a list of all the meta files 951updated. 952If not empty, it can be used to trigger processing of 953.Va .MAKE.META.FILES . 954.It Va .MAKE.META.FILES 955In "meta" mode, this variable contains a list of all the meta files 956used (updated or not). 957This list can be used to process the meta files to extract dependency 958information. 959.It Va .MAKE.META.IGNORE_PATHS 960Provides a list of path prefixes that should be ignored; 961because the contents are expected to change over time. 962The default list includes: 963.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp 964.It Va .MAKE.META.IGNORE_PATTERNS 965Provides a list of patterns to match against pathnames. 966Ignore any that match. 967.It Va .MAKE.META.IGNORE_FILTER 968Provides a list of variable modifiers to apply to each pathname. 969Ignore if the expansion is an empty string. 970.It Va .MAKE.META.PREFIX 971Defines the message printed for each meta file updated in "meta verbose" mode. 972The default value is: 973.Dl Building ${.TARGET:H:tA}/${.TARGET:T} 974.It Va .MAKEOVERRIDES 975This variable is used to record the names of variables assigned to 976on the command line, so that they may be exported as part of 977.Ql Ev MAKEFLAGS . 978This behavior can be disabled by assigning an empty value to 979.Ql Va .MAKEOVERRIDES 980within a makefile. 981Extra variables can be exported from a makefile 982by appending their names to 983.Ql Va .MAKEOVERRIDES . 984.Ql Ev MAKEFLAGS 985is re-exported whenever 986.Ql Va .MAKEOVERRIDES 987is modified. 988.It Va .MAKE.PATH_FILEMON 989If 990.Nm 991was built with 992.Xr filemon 4 993support, this is set to the path of the device node. 994This allows makefiles to test for this support. 995.It Va .MAKE.PID 996The process-id of 997.Nm . 998.It Va .MAKE.PPID 999The parent process-id of 1000.Nm . 1001.It Va .MAKE.SAVE_DOLLARS 1002value should be a boolean that controls whether 1003.Ql $$ 1004are preserved when doing 1005.Ql := 1006assignments. 1007The default is false, for backwards compatibility. 1008Set to true for compatability with other makes. 1009If set to false, 1010.Ql $$ 1011becomes 1012.Ql $ 1013per normal evaluation rules. 1014.It Va MAKE_PRINT_VAR_ON_ERROR 1015When 1016.Nm 1017stops due to an error, it sets 1018.Ql Va .ERROR_TARGET 1019to the name of the target that failed, 1020.Ql Va .ERROR_CMD 1021to the commands of the failed target, 1022and in "meta" mode, it also sets 1023.Ql Va .ERROR_CWD 1024to the 1025.Xr getcwd 3 , 1026and 1027.Ql Va .ERROR_META_FILE 1028to the path of the meta file (if any) describing the failed target. 1029It then prints its name and the value of 1030.Ql Va .CURDIR 1031as well as the value of any variables named in 1032.Ql Va MAKE_PRINT_VAR_ON_ERROR . 1033.It Va .newline 1034This variable is simply assigned a newline character as its value. 1035This allows expansions using the 1036.Cm \&:@ 1037modifier to put a newline between 1038iterations of the loop rather than a space. 1039For example, the printing of 1040.Ql Va MAKE_PRINT_VAR_ON_ERROR 1041could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}. 1042.It Va .OBJDIR 1043A path to the directory where the targets are built. 1044Its value is determined by trying to 1045.Xr chdir 2 1046to the following directories in order and using the first match: 1047.Bl -enum 1048.It 1049.Ev ${MAKEOBJDIRPREFIX}${.CURDIR} 1050.Pp 1051(Only if 1052.Ql Ev MAKEOBJDIRPREFIX 1053is set in the environment or on the command line.) 1054.It 1055.Ev ${MAKEOBJDIR} 1056.Pp 1057(Only if 1058.Ql Ev MAKEOBJDIR 1059is set in the environment or on the command line.) 1060.It 1061.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE} 1062.It 1063.Ev ${.CURDIR} Ns Pa /obj 1064.It 1065.Pa /usr/obj/ Ns Ev ${.CURDIR} 1066.It 1067.Ev ${.CURDIR} 1068.El 1069.Pp 1070Variable expansion is performed on the value before it's used, 1071so expressions such as 1072.Dl ${.CURDIR:S,^/usr/src,/var/obj,} 1073may be used. 1074This is especially useful with 1075.Ql Ev MAKEOBJDIR . 1076.Pp 1077.Ql Va .OBJDIR 1078may be modified in the makefile via the special target 1079.Ql Ic .OBJDIR . 1080In all cases, 1081.Nm 1082will 1083.Xr chdir 2 1084to the specified directory if it exists, and set 1085.Ql Va .OBJDIR 1086and 1087.Ql Ev PWD 1088to that directory before executing any targets. 1089. 1090.It Va .PARSEDIR 1091A path to the directory of the current 1092.Ql Pa Makefile 1093being parsed. 1094.It Va .PARSEFILE 1095The basename of the current 1096.Ql Pa Makefile 1097being parsed. 1098This variable and 1099.Ql Va .PARSEDIR 1100are both set only while the 1101.Ql Pa Makefiles 1102are being parsed. 1103If you want to retain their current values, assign them to a variable 1104using assignment with expansion: 1105.Pq Ql Cm \&:= . 1106.It Va .PATH 1107A variable that represents the list of directories that 1108.Nm 1109will search for files. 1110The search list should be updated using the target 1111.Ql Va .PATH 1112rather than the variable. 1113.It Ev PWD 1114Alternate path to the current directory. 1115.Nm 1116normally sets 1117.Ql Va .CURDIR 1118to the canonical path given by 1119.Xr getcwd 3 . 1120However, if the environment variable 1121.Ql Ev PWD 1122is set and gives a path to the current directory, then 1123.Nm 1124sets 1125.Ql Va .CURDIR 1126to the value of 1127.Ql Ev PWD 1128instead. 1129This behavior is disabled if 1130.Ql Ev MAKEOBJDIRPREFIX 1131is set or 1132.Ql Ev MAKEOBJDIR 1133contains a variable transform. 1134.Ql Ev PWD 1135is set to the value of 1136.Ql Va .OBJDIR 1137for all programs which 1138.Nm 1139executes. 1140.It Ev .TARGETS 1141The list of targets explicitly specified on the command line, if any. 1142.It Ev VPATH 1143Colon-separated 1144.Pq Dq \&: 1145lists of directories that 1146.Nm 1147will search for files. 1148The variable is supported for compatibility with old make programs only, 1149use 1150.Ql Va .PATH 1151instead. 1152.El 1153.Ss Variable modifiers 1154Variable expansion may be modified to select or modify each word of the 1155variable (where a 1156.Dq word 1157is white-space delimited sequence of characters). 1158The general format of a variable expansion is as follows: 1159.Pp 1160.Dl ${variable[:modifier[:...]]} 1161.Pp 1162Each modifier begins with a colon, 1163which may be escaped with a backslash 1164.Pq Ql \e . 1165.Pp 1166A set of modifiers can be specified via a variable, as follows: 1167.Pp 1168.Dl modifier_variable=modifier[:...] 1169.Dl ${variable:${modifier_variable}[:...]} 1170.Pp 1171In this case the first modifier in the modifier_variable does not 1172start with a colon, since that must appear in the referencing 1173variable. 1174If any of the modifiers in the modifier_variable contain a dollar sign 1175.Pq Ql $ , 1176these must be doubled to avoid early expansion. 1177.Pp 1178The supported modifiers are: 1179.Bl -tag -width EEE 1180.It Cm \&:E 1181Replaces each word in the variable with its suffix. 1182.It Cm \&:H 1183Replaces each word in the variable with everything but the last component. 1184.It Cm \&:M Ns Ar pattern 1185Select only those words that match 1186.Ar pattern . 1187The standard shell wildcard characters 1188.Pf ( Ql * , 1189.Ql \&? , 1190and 1191.Ql Oo Oc ) 1192may 1193be used. 1194The wildcard characters may be escaped with a backslash 1195.Pq Ql \e . 1196As a consequence of the way values are split into words, matched, 1197and then joined, a construct like 1198.Dl ${VAR:M*} 1199will normalize the inter-word spacing, removing all leading and 1200trailing space, and converting multiple consecutive spaces 1201to single spaces. 1202. 1203.It Cm \&:N Ns Ar pattern 1204This is identical to 1205.Ql Cm \&:M , 1206but selects all words which do not match 1207.Ar pattern . 1208.It Cm \&:O 1209Order every word in variable alphabetically. 1210To sort words in 1211reverse order use the 1212.Ql Cm \&:O:[-1..1] 1213combination of modifiers. 1214.It Cm \&:Ox 1215Randomize words in variable. 1216The results will be different each time you are referring to the 1217modified variable; use the assignment with expansion 1218.Pq Ql Cm \&:= 1219to prevent such behavior. 1220For example, 1221.Bd -literal -offset indent 1222LIST= uno due tre quattro 1223RANDOM_LIST= ${LIST:Ox} 1224STATIC_RANDOM_LIST:= ${LIST:Ox} 1225 1226all: 1227 @echo "${RANDOM_LIST}" 1228 @echo "${RANDOM_LIST}" 1229 @echo "${STATIC_RANDOM_LIST}" 1230 @echo "${STATIC_RANDOM_LIST}" 1231.Ed 1232may produce output similar to: 1233.Bd -literal -offset indent 1234quattro due tre uno 1235tre due quattro uno 1236due uno quattro tre 1237due uno quattro tre 1238.Ed 1239.It Cm \&:Q 1240Quotes every shell meta-character in the variable, so that it can be passed 1241safely through recursive invocations of 1242.Nm . 1243.It Cm \&:R 1244Replaces each word in the variable with everything but its suffix. 1245.It Cm \&:range[=count] 1246The value is an integer sequence representing the words of the original 1247value, or the supplied 1248.Va count . 1249.It Cm \&:gmtime[=utc] 1250The value is a format string for 1251.Xr strftime 3 , 1252using 1253.Xr gmtime 3 . 1254If a 1255.Va utc 1256value is not provided or is 0, the current time is used. 1257.It Cm \&:hash 1258Compute a 32-bit hash of the value and encode it as hex digits. 1259.It Cm \&:localtime[=utc] 1260The value is a format string for 1261.Xr strftime 3 , 1262using 1263.Xr localtime 3 . 1264If a 1265.Va utc 1266value is not provided or is 0, the current time is used. 1267.It Cm \&:tA 1268Attempt to convert variable to an absolute path using 1269.Xr realpath 3 , 1270if that fails, the value is unchanged. 1271.It Cm \&:tl 1272Converts variable to lower-case letters. 1273.It Cm \&:ts Ns Ar c 1274Words in the variable are normally separated by a space on expansion. 1275This modifier sets the separator to the character 1276.Ar c . 1277If 1278.Ar c 1279is omitted, then no separator is used. 1280The common escapes (including octal numeric codes), work as expected. 1281.It Cm \&:tu 1282Converts variable to upper-case letters. 1283.It Cm \&:tW 1284Causes the value to be treated as a single word 1285(possibly containing embedded white space). 1286See also 1287.Ql Cm \&:[*] . 1288.It Cm \&:tw 1289Causes the value to be treated as a sequence of 1290words delimited by white space. 1291See also 1292.Ql Cm \&:[@] . 1293.Sm off 1294.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW 1295.Sm on 1296Modify the first occurrence of 1297.Ar old_string 1298in the variable's value, replacing it with 1299.Ar new_string . 1300If a 1301.Ql g 1302is appended to the last slash of the pattern, all occurrences 1303in each word are replaced. 1304If a 1305.Ql 1 1306is appended to the last slash of the pattern, only the first word 1307is affected. 1308If a 1309.Ql W 1310is appended to the last slash of the pattern, 1311then the value is treated as a single word 1312(possibly containing embedded white space). 1313If 1314.Ar old_string 1315begins with a caret 1316.Pq Ql ^ , 1317.Ar old_string 1318is anchored at the beginning of each word. 1319If 1320.Ar old_string 1321ends with a dollar sign 1322.Pq Ql \&$ , 1323it is anchored at the end of each word. 1324Inside 1325.Ar new_string , 1326an ampersand 1327.Pq Ql & 1328is replaced by 1329.Ar old_string 1330(without any 1331.Ql ^ 1332or 1333.Ql \&$ ) . 1334Any character may be used as a delimiter for the parts of the modifier 1335string. 1336The anchoring, ampersand and delimiter characters may be escaped with a 1337backslash 1338.Pq Ql \e . 1339.Pp 1340Variable expansion occurs in the normal fashion inside both 1341.Ar old_string 1342and 1343.Ar new_string 1344with the single exception that a backslash is used to prevent the expansion 1345of a dollar sign 1346.Pq Ql \&$ , 1347not a preceding dollar sign as is usual. 1348.Sm off 1349.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW 1350.Sm on 1351The 1352.Cm \&:C 1353modifier is just like the 1354.Cm \&:S 1355modifier except that the old and new strings, instead of being 1356simple strings, are an extended regular expression (see 1357.Xr regex 3 ) 1358string 1359.Ar pattern 1360and an 1361.Xr ed 1 Ns \-style 1362string 1363.Ar replacement . 1364Normally, the first occurrence of the pattern 1365.Ar pattern 1366in each word of the value is substituted with 1367.Ar replacement . 1368The 1369.Ql 1 1370modifier causes the substitution to apply to at most one word; the 1371.Ql g 1372modifier causes the substitution to apply to as many instances of the 1373search pattern 1374.Ar pattern 1375as occur in the word or words it is found in; the 1376.Ql W 1377modifier causes the value to be treated as a single word 1378(possibly containing embedded white space). 1379Note that 1380.Ql 1 1381and 1382.Ql g 1383are orthogonal; the former specifies whether multiple words are 1384potentially affected, the latter whether multiple substitutions can 1385potentially occur within each affected word. 1386.Pp 1387As for the 1388.Cm \&:S 1389modifier, the 1390.Ar pattern 1391and 1392.Ar replacement 1393are subjected to variable expansion before being parsed as 1394regular expressions. 1395.It Cm \&:T 1396Replaces each word in the variable with its last component. 1397.It Cm \&:u 1398Remove adjacent duplicate words (like 1399.Xr uniq 1 ) . 1400.Sm off 1401.It Cm \&:\&? Ar true_string Cm \&: Ar false_string 1402.Sm on 1403If the variable name (not its value), when parsed as a .if conditional 1404expression, evaluates to true, return as its value the 1405.Ar true_string , 1406otherwise return the 1407.Ar false_string . 1408Since the variable name is used as the expression, \&:\&? must be the 1409first modifier after the variable name itself - which will, of course, 1410usually contain variable expansions. 1411A common error is trying to use expressions like 1412.Dl ${NUMBERS:M42:?match:no} 1413which actually tests defined(NUMBERS), 1414to determine is any words match "42" you need to use something like: 1415.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} . 1416.It Ar :old_string=new_string 1417This is the 1418.At V 1419style variable substitution. 1420It must be the last modifier specified. 1421If 1422.Ar old_string 1423or 1424.Ar new_string 1425do not contain the pattern matching character 1426.Ar % 1427then it is assumed that they are 1428anchored at the end of each word, so only suffixes or entire 1429words may be replaced. 1430Otherwise 1431.Ar % 1432is the substring of 1433.Ar old_string 1434to be replaced in 1435.Ar new_string . 1436.Pp 1437Variable expansion occurs in the normal fashion inside both 1438.Ar old_string 1439and 1440.Ar new_string 1441with the single exception that a backslash is used to prevent the 1442expansion of a dollar sign 1443.Pq Ql \&$ , 1444not a preceding dollar sign as is usual. 1445.Sm off 1446.It Cm \&:@ Ar temp Cm @ Ar string Cm @ 1447.Sm on 1448This is the loop expansion mechanism from the OSF Development 1449Environment (ODE) make. 1450Unlike 1451.Cm \&.for 1452loops expansion occurs at the time of 1453reference. 1454Assign 1455.Ar temp 1456to each word in the variable and evaluate 1457.Ar string . 1458The ODE convention is that 1459.Ar temp 1460should start and end with a period. 1461For example. 1462.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@} 1463.Pp 1464However a single character variable is often more readable: 1465.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@} 1466.It Cm \&:_[=var] 1467Save the current variable value in 1468.Ql $_ 1469or the named 1470.Va var 1471for later reference. 1472Example usage: 1473.Bd -literal -offset indent 1474M_cmpv.units = 1 1000 1000000 1475M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\ 1476\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh 1477 1478.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}} 1479 1480.Ed 1481Here 1482.Ql $_ 1483is used to save the result of the 1484.Ql :S 1485modifier which is later referenced using the index values from 1486.Ql :range . 1487.It Cm \&:U Ns Ar newval 1488If the variable is undefined 1489.Ar newval 1490is the value. 1491If the variable is defined, the existing value is returned. 1492This is another ODE make feature. 1493It is handy for setting per-target CFLAGS for instance: 1494.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}} 1495If a value is only required if the variable is undefined, use: 1496.Dl ${VAR:D:Unewval} 1497.It Cm \&:D Ns Ar newval 1498If the variable is defined 1499.Ar newval 1500is the value. 1501.It Cm \&:L 1502The name of the variable is the value. 1503.It Cm \&:P 1504The path of the node which has the same name as the variable 1505is the value. 1506If no such node exists or its path is null, then the 1507name of the variable is used. 1508In order for this modifier to work, the name (node) must at least have 1509appeared on the rhs of a dependency. 1510.Sm off 1511.It Cm \&:\&! Ar cmd Cm \&! 1512.Sm on 1513The output of running 1514.Ar cmd 1515is the value. 1516.It Cm \&:sh 1517If the variable is non-empty it is run as a command and the output 1518becomes the new value. 1519.It Cm \&::= Ns Ar str 1520The variable is assigned the value 1521.Ar str 1522after substitution. 1523This modifier and its variations are useful in 1524obscure situations such as wanting to set a variable when shell commands 1525are being parsed. 1526These assignment modifiers always expand to 1527nothing, so if appearing in a rule line by themselves should be 1528preceded with something to keep 1529.Nm 1530happy. 1531.Pp 1532The 1533.Ql Cm \&:: 1534helps avoid false matches with the 1535.At V 1536style 1537.Cm \&:= 1538modifier and since substitution always occurs the 1539.Cm \&::= 1540form is vaguely appropriate. 1541.It Cm \&::?= Ns Ar str 1542As for 1543.Cm \&::= 1544but only if the variable does not already have a value. 1545.It Cm \&::+= Ns Ar str 1546Append 1547.Ar str 1548to the variable. 1549.It Cm \&::!= Ns Ar cmd 1550Assign the output of 1551.Ar cmd 1552to the variable. 1553.It Cm \&:\&[ Ns Ar range Ns Cm \&] 1554Selects one or more words from the value, 1555or performs other operations related to the way in which the 1556value is divided into words. 1557.Pp 1558Ordinarily, a value is treated as a sequence of words 1559delimited by white space. 1560Some modifiers suppress this behavior, 1561causing a value to be treated as a single word 1562(possibly containing embedded white space). 1563An empty value, or a value that consists entirely of white-space, 1564is treated as a single word. 1565For the purposes of the 1566.Ql Cm \&:[] 1567modifier, the words are indexed both forwards using positive integers 1568(where index 1 represents the first word), 1569and backwards using negative integers 1570(where index \-1 represents the last word). 1571.Pp 1572The 1573.Ar range 1574is subjected to variable expansion, and the expanded result is 1575then interpreted as follows: 1576.Bl -tag -width index 1577.\" :[n] 1578.It Ar index 1579Selects a single word from the value. 1580.\" :[start..end] 1581.It Ar start Ns Cm \&.. Ns Ar end 1582Selects all words from 1583.Ar start 1584to 1585.Ar end , 1586inclusive. 1587For example, 1588.Ql Cm \&:[2..-1] 1589selects all words from the second word to the last word. 1590If 1591.Ar start 1592is greater than 1593.Ar end , 1594then the words are output in reverse order. 1595For example, 1596.Ql Cm \&:[-1..1] 1597selects all the words from last to first. 1598.\" :[*] 1599.It Cm \&* 1600Causes subsequent modifiers to treat the value as a single word 1601(possibly containing embedded white space). 1602Analogous to the effect of 1603\&"$*\&" 1604in Bourne shell. 1605.\" :[0] 1606.It 0 1607Means the same as 1608.Ql Cm \&:[*] . 1609.\" :[*] 1610.It Cm \&@ 1611Causes subsequent modifiers to treat the value as a sequence of words 1612delimited by white space. 1613Analogous to the effect of 1614\&"$@\&" 1615in Bourne shell. 1616.\" :[#] 1617.It Cm \&# 1618Returns the number of words in the value. 1619.El \" :[range] 1620.El 1621.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS 1622Makefile inclusion, conditional structures and for loops reminiscent 1623of the C programming language are provided in 1624.Nm . 1625All such structures are identified by a line beginning with a single 1626dot 1627.Pq Ql \&. 1628character. 1629Files are included with either 1630.Cm \&.include Aq Ar file 1631or 1632.Cm \&.include Pf \*q Ar file Ns \*q . 1633Variables between the angle brackets or double quotes are expanded 1634to form the file name. 1635If angle brackets are used, the included makefile is expected to be in 1636the system makefile directory. 1637If double quotes are used, the including makefile's directory and any 1638directories specified using the 1639.Fl I 1640option are searched before the system 1641makefile directory. 1642For compatibility with other versions of 1643.Nm 1644.Ql include file ... 1645is also accepted. 1646.Pp 1647If the include statement is written as 1648.Cm .-include 1649or as 1650.Cm .sinclude 1651then errors locating and/or opening include files are ignored. 1652.Pp 1653If the include statement is written as 1654.Cm .dinclude 1655not only are errors locating and/or opening include files ignored, 1656but stale dependencies within the included file will be ignored 1657just like 1658.Va .MAKE.DEPENDFILE . 1659.Pp 1660Conditional expressions are also preceded by a single dot as the first 1661character of a line. 1662The possible conditionals are as follows: 1663.Bl -tag -width Ds 1664.It Ic .error Ar message 1665The message is printed along with the name of the makefile and line number, 1666then 1667.Nm 1668will exit. 1669.It Ic .export Ar variable ... 1670Export the specified global variable. 1671If no variable list is provided, all globals are exported 1672except for internal variables (those that start with 1673.Ql \&. ) . 1674This is not affected by the 1675.Fl X 1676flag, so should be used with caution. 1677For compatibility with other 1678.Nm 1679programs 1680.Ql export variable=value 1681is also accepted. 1682.Pp 1683Appending a variable name to 1684.Va .MAKE.EXPORTED 1685is equivalent to exporting a variable. 1686.It Ic .export-env Ar variable ... 1687The same as 1688.Ql .export , 1689except that the variable is not appended to 1690.Va .MAKE.EXPORTED . 1691This allows exporting a value to the environment which is different from that 1692used by 1693.Nm 1694internally. 1695.It Ic .export-literal Ar variable ... 1696The same as 1697.Ql .export-env , 1698except that variables in the value are not expanded. 1699.It Ic .info Ar message 1700The message is printed along with the name of the makefile and line number. 1701.It Ic .undef Ar variable 1702Un-define the specified global variable. 1703Only global variables may be un-defined. 1704.It Ic .unexport Ar variable ... 1705The opposite of 1706.Ql .export . 1707The specified global 1708.Va variable 1709will be removed from 1710.Va .MAKE.EXPORTED . 1711If no variable list is provided, all globals are unexported, 1712and 1713.Va .MAKE.EXPORTED 1714deleted. 1715.It Ic .unexport-env 1716Unexport all globals previously exported and 1717clear the environment inherited from the parent. 1718This operation will cause a memory leak of the original environment, 1719so should be used sparingly. 1720Testing for 1721.Va .MAKE.LEVEL 1722being 0, would make sense. 1723Also note that any variables which originated in the parent environment 1724should be explicitly preserved if desired. 1725For example: 1726.Bd -literal -offset indent 1727.Li .if ${.MAKE.LEVEL} == 0 1728PATH := ${PATH} 1729.Li .unexport-env 1730.Li .export PATH 1731.Li .endif 1732.Pp 1733.Ed 1734Would result in an environment containing only 1735.Ql Ev PATH , 1736which is the minimal useful environment. 1737Actually 1738.Ql Ev .MAKE.LEVEL 1739will also be pushed into the new environment. 1740.It Ic .warning Ar message 1741The message prefixed by 1742.Ql Pa warning: 1743is printed along with the name of the makefile and line number. 1744.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ... 1745Test the value of an expression. 1746.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1747Test the value of a variable. 1748.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1749Test the value of a variable. 1750.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1751Test the target being built. 1752.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ... 1753Test the target being built. 1754.It Ic .else 1755Reverse the sense of the last conditional. 1756.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ... 1757A combination of 1758.Ql Ic .else 1759followed by 1760.Ql Ic .if . 1761.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1762A combination of 1763.Ql Ic .else 1764followed by 1765.Ql Ic .ifdef . 1766.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1767A combination of 1768.Ql Ic .else 1769followed by 1770.Ql Ic .ifndef . 1771.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1772A combination of 1773.Ql Ic .else 1774followed by 1775.Ql Ic .ifmake . 1776.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1777A combination of 1778.Ql Ic .else 1779followed by 1780.Ql Ic .ifnmake . 1781.It Ic .endif 1782End the body of the conditional. 1783.El 1784.Pp 1785The 1786.Ar operator 1787may be any one of the following: 1788.Bl -tag -width "Cm XX" 1789.It Cm \&|\&| 1790Logical OR. 1791.It Cm \&&& 1792Logical 1793.Tn AND ; 1794of higher precedence than 1795.Dq \&|\&| . 1796.El 1797.Pp 1798As in C, 1799.Nm 1800will only evaluate a conditional as far as is necessary to determine 1801its value. 1802Parentheses may be used to change the order of evaluation. 1803The boolean operator 1804.Ql Ic \&! 1805may be used to logically negate an entire 1806conditional. 1807It is of higher precedence than 1808.Ql Ic \&&& . 1809.Pp 1810The value of 1811.Ar expression 1812may be any of the following: 1813.Bl -tag -width defined 1814.It Ic defined 1815Takes a variable name as an argument and evaluates to true if the variable 1816has been defined. 1817.It Ic make 1818Takes a target name as an argument and evaluates to true if the target 1819was specified as part of 1820.Nm Ns 's 1821command line or was declared the default target (either implicitly or 1822explicitly, see 1823.Va .MAIN ) 1824before the line containing the conditional. 1825.It Ic empty 1826Takes a variable, with possible modifiers, and evaluates to true if 1827the expansion of the variable would result in an empty string. 1828.It Ic exists 1829Takes a file name as an argument and evaluates to true if the file exists. 1830The file is searched for on the system search path (see 1831.Va .PATH ) . 1832.It Ic target 1833Takes a target name as an argument and evaluates to true if the target 1834has been defined. 1835.It Ic commands 1836Takes a target name as an argument and evaluates to true if the target 1837has been defined and has commands associated with it. 1838.El 1839.Pp 1840.Ar Expression 1841may also be an arithmetic or string comparison. 1842Variable expansion is 1843performed on both sides of the comparison, after which the integral 1844values are compared. 1845A value is interpreted as hexadecimal if it is 1846preceded by 0x, otherwise it is decimal; octal numbers are not supported. 1847The standard C relational operators are all supported. 1848If after 1849variable expansion, either the left or right hand side of a 1850.Ql Ic == 1851or 1852.Ql Ic "!=" 1853operator is not an integral value, then 1854string comparison is performed between the expanded 1855variables. 1856If no relational operator is given, it is assumed that the expanded 1857variable is being compared against 0 or an empty string in the case 1858of a string comparison. 1859.Pp 1860When 1861.Nm 1862is evaluating one of these conditional expressions, and it encounters 1863a (white-space separated) word it doesn't recognize, either the 1864.Dq make 1865or 1866.Dq defined 1867expression is applied to it, depending on the form of the conditional. 1868If the form is 1869.Ql Ic .ifdef , 1870.Ql Ic .ifndef , 1871or 1872.Ql Ic .if 1873the 1874.Dq defined 1875expression is applied. 1876Similarly, if the form is 1877.Ql Ic .ifmake 1878or 1879.Ql Ic .ifnmake , the 1880.Dq make 1881expression is applied. 1882.Pp 1883If the conditional evaluates to true the parsing of the makefile continues 1884as before. 1885If it evaluates to false, the following lines are skipped. 1886In both cases this continues until a 1887.Ql Ic .else 1888or 1889.Ql Ic .endif 1890is found. 1891.Pp 1892For loops are typically used to apply a set of rules to a list of files. 1893The syntax of a for loop is: 1894.Pp 1895.Bl -tag -compact -width Ds 1896.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression 1897.It Aq make-rules 1898.It Ic \&.endfor 1899.El 1900.Pp 1901After the for 1902.Ic expression 1903is evaluated, it is split into words. 1904On each iteration of the loop, one word is taken and assigned to each 1905.Ic variable , 1906in order, and these 1907.Ic variables 1908are substituted into the 1909.Ic make-rules 1910inside the body of the for loop. 1911The number of words must come out even; that is, if there are three 1912iteration variables, the number of words provided must be a multiple 1913of three. 1914.Sh COMMENTS 1915Comments begin with a hash 1916.Pq Ql \&# 1917character, anywhere but in a shell 1918command line, and continue to the end of an unescaped new line. 1919.Sh SPECIAL SOURCES (ATTRIBUTES) 1920.Bl -tag -width .IGNOREx 1921.It Ic .EXEC 1922Target is never out of date, but always execute commands anyway. 1923.It Ic .IGNORE 1924Ignore any errors from the commands associated with this target, exactly 1925as if they all were preceded by a dash 1926.Pq Ql \- . 1927.\" .It Ic .INVISIBLE 1928.\" XXX 1929.\" .It Ic .JOIN 1930.\" XXX 1931.It Ic .MADE 1932Mark all sources of this target as being up-to-date. 1933.It Ic .MAKE 1934Execute the commands associated with this target even if the 1935.Fl n 1936or 1937.Fl t 1938options were specified. 1939Normally used to mark recursive 1940.Nm Ns s . 1941.It Ic .META 1942Create a meta file for the target, even if it is flagged as 1943.Ic .PHONY , 1944.Ic .MAKE , 1945or 1946.Ic .SPECIAL . 1947Usage in conjunction with 1948.Ic .MAKE 1949is the most likely case. 1950In "meta" mode, the target is out-of-date if the meta file is missing. 1951.It Ic .NOMETA 1952Do not create a meta file for the target. 1953Meta files are also not created for 1954.Ic .PHONY , 1955.Ic .MAKE , 1956or 1957.Ic .SPECIAL 1958targets. 1959.It Ic .NOMETA_CMP 1960Ignore differences in commands when deciding if target is out of date. 1961This is useful if the command contains a value which always changes. 1962If the number of commands change, though, the target will still be out of date. 1963The same effect applies to any command line that uses the variable 1964.Va .OODATE , 1965which can be used for that purpose even when not otherwise needed or desired: 1966.Bd -literal -offset indent 1967 1968skip-compare-for-some: 1969 @echo this will be compared 1970 @echo this will not ${.OODATE:M.NOMETA_CMP} 1971 @echo this will also be compared 1972 1973.Ed 1974The 1975.Cm \&:M 1976pattern suppresses any expansion of the unwanted variable. 1977.It Ic .NOPATH 1978Do not search for the target in the directories specified by 1979.Ic .PATH . 1980.It Ic .NOTMAIN 1981Normally 1982.Nm 1983selects the first target it encounters as the default target to be built 1984if no target was specified. 1985This source prevents this target from being selected. 1986.It Ic .OPTIONAL 1987If a target is marked with this attribute and 1988.Nm 1989can't figure out how to create it, it will ignore this fact and assume 1990the file isn't needed or already exists. 1991.It Ic .PHONY 1992The target does not 1993correspond to an actual file; it is always considered to be out of date, 1994and will not be created with the 1995.Fl t 1996option. 1997Suffix-transformation rules are not applied to 1998.Ic .PHONY 1999targets. 2000.It Ic .PRECIOUS 2001When 2002.Nm 2003is interrupted, it normally removes any partially made targets. 2004This source prevents the target from being removed. 2005.It Ic .RECURSIVE 2006Synonym for 2007.Ic .MAKE . 2008.It Ic .SILENT 2009Do not echo any of the commands associated with this target, exactly 2010as if they all were preceded by an at sign 2011.Pq Ql @ . 2012.It Ic .USE 2013Turn the target into 2014.Nm Ns 's 2015version of a macro. 2016When the target is used as a source for another target, the other target 2017acquires the commands, sources, and attributes (except for 2018.Ic .USE ) 2019of the 2020source. 2021If the target already has commands, the 2022.Ic .USE 2023target's commands are appended 2024to them. 2025.It Ic .USEBEFORE 2026Exactly like 2027.Ic .USE , 2028but prepend the 2029.Ic .USEBEFORE 2030target commands to the target. 2031.It Ic .WAIT 2032If 2033.Ic .WAIT 2034appears in a dependency line, the sources that precede it are 2035made before the sources that succeed it in the line. 2036Since the dependents of files are not made until the file itself 2037could be made, this also stops the dependents being built unless they 2038are needed for another branch of the dependency tree. 2039So given: 2040.Bd -literal 2041x: a .WAIT b 2042 echo x 2043a: 2044 echo a 2045b: b1 2046 echo b 2047b1: 2048 echo b1 2049 2050.Ed 2051the output is always 2052.Ql a , 2053.Ql b1 , 2054.Ql b , 2055.Ql x . 2056.br 2057The ordering imposed by 2058.Ic .WAIT 2059is only relevant for parallel makes. 2060.El 2061.Sh SPECIAL TARGETS 2062Special targets may not be included with other targets, i.e. they must be 2063the only target specified. 2064.Bl -tag -width .BEGINx 2065.It Ic .BEGIN 2066Any command lines attached to this target are executed before anything 2067else is done. 2068.It Ic .DEFAULT 2069This is sort of a 2070.Ic .USE 2071rule for any target (that was used only as a 2072source) that 2073.Nm 2074can't figure out any other way to create. 2075Only the shell script is used. 2076The 2077.Ic .IMPSRC 2078variable of a target that inherits 2079.Ic .DEFAULT Ns 's 2080commands is set 2081to the target's own name. 2082.It Ic .DELETE_ON_ERROR 2083If this target is present in the makefile, it globally causes make to 2084delete targets whose commands fail. 2085(By default, only targets whose commands are interrupted during 2086execution are deleted. 2087This is the historical behavior.) 2088This setting can be used to help prevent half-finished or malformed 2089targets from being left around and corrupting future rebuilds. 2090.It Ic .END 2091Any command lines attached to this target are executed after everything 2092else is done. 2093.It Ic .ERROR 2094Any command lines attached to this target are executed when another target fails. 2095The 2096.Ic .ERROR_TARGET 2097variable is set to the target that failed. 2098See also 2099.Ic MAKE_PRINT_VAR_ON_ERROR . 2100.It Ic .IGNORE 2101Mark each of the sources with the 2102.Ic .IGNORE 2103attribute. 2104If no sources are specified, this is the equivalent of specifying the 2105.Fl i 2106option. 2107.It Ic .INTERRUPT 2108If 2109.Nm 2110is interrupted, the commands for this target will be executed. 2111.It Ic .MAIN 2112If no target is specified when 2113.Nm 2114is invoked, this target will be built. 2115.It Ic .MAKEFLAGS 2116This target provides a way to specify flags for 2117.Nm 2118when the makefile is used. 2119The flags are as if typed to the shell, though the 2120.Fl f 2121option will have 2122no effect. 2123.\" XXX: NOT YET!!!! 2124.\" .It Ic .NOTPARALLEL 2125.\" The named targets are executed in non parallel mode. 2126.\" If no targets are 2127.\" specified, then all targets are executed in non parallel mode. 2128.It Ic .NOPATH 2129Apply the 2130.Ic .NOPATH 2131attribute to any specified sources. 2132.It Ic .NOTPARALLEL 2133Disable parallel mode. 2134.It Ic .NO_PARALLEL 2135Synonym for 2136.Ic .NOTPARALLEL , 2137for compatibility with other pmake variants. 2138.It Ic .OBJDIR 2139The source is a new value for 2140.Ql Va .OBJDIR . 2141If it exists, 2142.Nm 2143will 2144.Xr chdir 2 2145to it and update the value of 2146.Ql Va .OBJDIR . 2147.It Ic .ORDER 2148The named targets are made in sequence. 2149This ordering does not add targets to the list of targets to be made. 2150Since the dependents of a target do not get built until the target itself 2151could be built, unless 2152.Ql a 2153is built by another part of the dependency graph, 2154the following is a dependency loop: 2155.Bd -literal 2156\&.ORDER: b a 2157b: a 2158.Ed 2159.Pp 2160The ordering imposed by 2161.Ic .ORDER 2162is only relevant for parallel makes. 2163.\" XXX: NOT YET!!!! 2164.\" .It Ic .PARALLEL 2165.\" The named targets are executed in parallel mode. 2166.\" If no targets are 2167.\" specified, then all targets are executed in parallel mode. 2168.It Ic .PATH 2169The sources are directories which are to be searched for files not 2170found in the current directory. 2171If no sources are specified, any previously specified directories are 2172deleted. 2173If the source is the special 2174.Ic .DOTLAST 2175target, then the current working 2176directory is searched last. 2177.It Ic .PATH. Ns Va suffix 2178Like 2179.Ic .PATH 2180but applies only to files with a particular suffix. 2181The suffix must have been previously declared with 2182.Ic .SUFFIXES . 2183.It Ic .PHONY 2184Apply the 2185.Ic .PHONY 2186attribute to any specified sources. 2187.It Ic .PRECIOUS 2188Apply the 2189.Ic .PRECIOUS 2190attribute to any specified sources. 2191If no sources are specified, the 2192.Ic .PRECIOUS 2193attribute is applied to every 2194target in the file. 2195.It Ic .SHELL 2196Sets the shell that 2197.Nm 2198will use to execute commands. 2199The sources are a set of 2200.Ar field=value 2201pairs. 2202.Bl -tag -width hasErrCtls 2203.It Ar name 2204This is the minimal specification, used to select one of the built-in 2205shell specs; 2206.Ar sh , 2207.Ar ksh , 2208and 2209.Ar csh . 2210.It Ar path 2211Specifies the path to the shell. 2212.It Ar hasErrCtl 2213Indicates whether the shell supports exit on error. 2214.It Ar check 2215The command to turn on error checking. 2216.It Ar ignore 2217The command to disable error checking. 2218.It Ar echo 2219The command to turn on echoing of commands executed. 2220.It Ar quiet 2221The command to turn off echoing of commands executed. 2222.It Ar filter 2223The output to filter after issuing the 2224.Ar quiet 2225command. 2226It is typically identical to 2227.Ar quiet . 2228.It Ar errFlag 2229The flag to pass the shell to enable error checking. 2230.It Ar echoFlag 2231The flag to pass the shell to enable command echoing. 2232.It Ar newline 2233The string literal to pass the shell that results in a single newline 2234character when used outside of any quoting characters. 2235.El 2236Example: 2237.Bd -literal 2238\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e 2239 check="set \-e" ignore="set +e" \e 2240 echo="set \-v" quiet="set +v" filter="set +v" \e 2241 echoFlag=v errFlag=e newline="'\en'" 2242.Ed 2243.It Ic .SILENT 2244Apply the 2245.Ic .SILENT 2246attribute to any specified sources. 2247If no sources are specified, the 2248.Ic .SILENT 2249attribute is applied to every 2250command in the file. 2251.It Ic .STALE 2252This target gets run when a dependency file contains stale entries, having 2253.Va .ALLSRC 2254set to the name of that dependency file. 2255.It Ic .SUFFIXES 2256Each source specifies a suffix to 2257.Nm . 2258If no sources are specified, any previously specified suffixes are deleted. 2259It allows the creation of suffix-transformation rules. 2260.Pp 2261Example: 2262.Bd -literal 2263\&.SUFFIXES: .o 2264\&.c.o: 2265 cc \-o ${.TARGET} \-c ${.IMPSRC} 2266.Ed 2267.El 2268.Sh ENVIRONMENT 2269.Nm 2270uses the following environment variables, if they exist: 2271.Ev MACHINE , 2272.Ev MACHINE_ARCH , 2273.Ev MAKE , 2274.Ev MAKEFLAGS , 2275.Ev MAKEOBJDIR , 2276.Ev MAKEOBJDIRPREFIX , 2277.Ev MAKESYSPATH , 2278.Ev PWD , 2279and 2280.Ev TMPDIR . 2281.Pp 2282.Ev MAKEOBJDIRPREFIX 2283and 2284.Ev MAKEOBJDIR 2285may only be set in the environment or on the command line to 2286.Nm 2287and not as makefile variables; 2288see the description of 2289.Ql Va .OBJDIR 2290for more details. 2291.Sh FILES 2292.Bl -tag -width /usr/share/mk -compact 2293.It .depend 2294list of dependencies 2295.It Makefile 2296list of dependencies 2297.It makefile 2298list of dependencies 2299.It sys.mk 2300system makefile 2301.It /usr/share/mk 2302system makefile directory 2303.El 2304.Sh COMPATIBILITY 2305The basic make syntax is compatible between different versions of make; 2306however the special variables, variable modifiers and conditionals are not. 2307.Ss Older versions 2308An incomplete list of changes in older versions of 2309.Nm : 2310.Pp 2311The way that .for loop variables are substituted changed after 2312.Nx 5.0 2313so that they still appear to be variable expansions. 2314In particular this stops them being treated as syntax, and removes some 2315obscure problems using them in .if statements. 2316.Pp 2317The way that parallel makes are scheduled changed in 2318.Nx 4.0 2319so that .ORDER and .WAIT apply recursively to the dependent nodes. 2320The algorithms used may change again in the future. 2321.Ss Other make dialects 2322Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not 2323support most of the features of 2324.Nm 2325as described in this manual. 2326Most notably: 2327.Bl -bullet -offset indent 2328.It 2329The 2330.Ic .WAIT 2331and 2332.Ic .ORDER 2333declarations and most functionality pertaining to parallelization. 2334(GNU make supports parallelization but lacks these features needed to 2335control it effectively.) 2336.It 2337Directives, including for loops and conditionals and most of the 2338forms of include files. 2339(GNU make has its own incompatible and less powerful syntax for 2340conditionals.) 2341.It 2342All built-in variables that begin with a dot. 2343.It 2344Most of the special sources and targets that begin with a dot, 2345with the notable exception of 2346.Ic .PHONY , 2347.Ic .PRECIOUS , 2348and 2349.Ic .SUFFIXES . 2350.It 2351Variable modifiers, except for the 2352.Dl :old=new 2353string substitution, which does not portably support globbing with 2354.Ql % 2355and historically only works on declared suffixes. 2356.It 2357The 2358.Ic $> 2359variable even in its short form; most makes support this functionality 2360but its name varies. 2361.El 2362.Pp 2363Some features are somewhat more portable, such as assignment with 2364.Ic += , 2365.Ic ?= , 2366and 2367.Ic != . 2368The 2369.Ic .PATH 2370functionality is based on an older feature 2371.Ic VPATH 2372found in GNU make and many versions of SVR4 make; however, 2373historically its behavior is too ill-defined (and too buggy) to rely 2374upon. 2375.Pp 2376The 2377.Ic $@ 2378and 2379.Ic $< 2380variables are more or less universally portable, as is the 2381.Ic $(MAKE) 2382variable. 2383Basic use of suffix rules (for files only in the current directory, 2384not trying to chain transformations together, etc.) is also reasonably 2385portable. 2386.Sh SEE ALSO 2387.Xr mkdep 1 2388.Sh HISTORY 2389A 2390.Nm 2391command appeared in 2392.At v7 . 2393This 2394.Nm 2395implementation is based on Adam De Boor's pmake program which was written 2396for Sprite at Berkeley. 2397It was designed to be a parallel distributed make running jobs on different 2398machines using a daemon called 2399.Dq customs . 2400.Pp 2401Historically the target/dependency 2402.Dq FRC 2403has been used to FoRCe rebuilding (since the target/dependency 2404does not exist... unless someone creates an 2405.Dq FRC 2406file). 2407.Sh BUGS 2408The 2409.Nm 2410syntax is difficult to parse without actually acting of the data. 2411For instance finding the end of a variable use should involve scanning each 2412the modifiers using the correct terminator for each field. 2413In many places 2414.Nm 2415just counts {} and () in order to find the end of a variable expansion. 2416.Pp 2417There is no way of escaping a space character in a filename. 2418