1.\" $NetBSD: make.1,v 1.282 2020/06/06 20:28:42 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 5, 2020 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.Li \&< Ns Ar file Ns Li \&> 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.Li \*q Ns Ar file Ns Li \*q 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.DEPENDFILE 794Names the makefile (default 795.Ql Pa .depend ) 796from which generated dependencies are read. 797.It Va .MAKE.EXPAND_VARIABLES 798A boolean that controls the default behavior of the 799.Fl V 800option. 801If true, variable values printed with 802.Fl V 803are fully expanded; if false, the raw variable contents (which may 804include additional unexpanded variable references) are shown. 805.It Va .MAKE.EXPORTED 806The list of variables exported by 807.Nm . 808.It Va .MAKE.JOBS 809The argument to the 810.Fl j 811option. 812.It Va .MAKE.JOB.PREFIX 813If 814.Nm 815is run with 816.Ar j 817then output for each target is prefixed with a token 818.Ql --- target --- 819the first part of which can be controlled via 820.Va .MAKE.JOB.PREFIX . 821If 822.Va .MAKE.JOB.PREFIX 823is empty, no token is printed. 824.br 825For example: 826.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}] 827would produce tokens like 828.Ql ---make[1234] target --- 829making it easier to track the degree of parallelism being achieved. 830.It Ev MAKEFLAGS 831The environment variable 832.Ql Ev MAKEFLAGS 833may contain anything that 834may be specified on 835.Nm Ns 's 836command line. 837Anything specified on 838.Nm Ns 's 839command line is appended to the 840.Ql Ev MAKEFLAGS 841variable which is then 842entered into the environment for all programs which 843.Nm 844executes. 845.It Va .MAKE.LEVEL 846The recursion depth of 847.Nm . 848The initial instance of 849.Nm 850will be 0, and an incremented value is put into the environment 851to be seen by the next generation. 852This allows tests like: 853.Li .if ${.MAKE.LEVEL} == 0 854to protect things which should only be evaluated in the initial instance of 855.Nm . 856.It Va .MAKE.MAKEFILE_PREFERENCE 857The ordered list of makefile names 858(default 859.Ql Pa makefile , 860.Ql Pa Makefile ) 861that 862.Nm 863will look for. 864.It Va .MAKE.MAKEFILES 865The list of makefiles read by 866.Nm , 867which is useful for tracking dependencies. 868Each makefile is recorded only once, regardless of the number of times read. 869.It Va .MAKE.MODE 870Processed after reading all makefiles. 871Can affect the mode that 872.Nm 873runs in. 874It can contain a number of keywords: 875.Bl -hang -width missing-filemon=bf. 876.It Pa compat 877Like 878.Fl B , 879puts 880.Nm 881into "compat" mode. 882.It Pa meta 883Puts 884.Nm 885into "meta" mode, where meta files are created for each target 886to capture the command run, the output generated and if 887.Xr filemon 4 888is available, the system calls which are of interest to 889.Nm . 890The captured output can be very useful when diagnosing errors. 891.It Pa curdirOk= Ar bf 892Normally 893.Nm 894will not create .meta files in 895.Ql Va .CURDIR . 896This can be overridden by setting 897.Va bf 898to a value which represents True. 899.It Pa missing-meta= Ar bf 900If 901.Va bf 902is True, then a missing .meta file makes the target out-of-date. 903.It Pa missing-filemon= Ar bf 904If 905.Va bf 906is True, then missing filemon data makes the target out-of-date. 907.It Pa nofilemon 908Do not use 909.Xr filemon 4 . 910.It Pa env 911For debugging, it can be useful to include the environment 912in the .meta file. 913.It Pa verbose 914If in "meta" mode, print a clue about the target being built. 915This is useful if the build is otherwise running silently. 916The message printed the value of: 917.Va .MAKE.META.PREFIX . 918.It Pa ignore-cmd 919Some makefiles have commands which are simply not stable. 920This keyword causes them to be ignored for 921determining whether a target is out of date in "meta" mode. 922See also 923.Ic .NOMETA_CMP . 924.It Pa silent= Ar bf 925If 926.Va bf 927is True, when a .meta file is created, mark the target 928.Ic .SILENT . 929.El 930.It Va .MAKE.META.BAILIWICK 931In "meta" mode, provides a list of prefixes which 932match the directories controlled by 933.Nm . 934If a file that was generated outside of 935.Va .OBJDIR 936but within said bailiwick is missing, 937the current target is considered out-of-date. 938.It Va .MAKE.META.CREATED 939In "meta" mode, this variable contains a list of all the meta files 940updated. 941If not empty, it can be used to trigger processing of 942.Va .MAKE.META.FILES . 943.It Va .MAKE.META.FILES 944In "meta" mode, this variable contains a list of all the meta files 945used (updated or not). 946This list can be used to process the meta files to extract dependency 947information. 948.It Va .MAKE.META.IGNORE_PATHS 949Provides a list of path prefixes that should be ignored; 950because the contents are expected to change over time. 951The default list includes: 952.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp 953.It Va .MAKE.META.IGNORE_PATTERNS 954Provides a list of patterns to match against pathnames. 955Ignore any that match. 956.It Va .MAKE.META.IGNORE_FILTER 957Provides a list of variable modifiers to apply to each pathname. 958Ignore if the expansion is an empty string. 959.It Va .MAKE.META.PREFIX 960Defines the message printed for each meta file updated in "meta verbose" mode. 961The default value is: 962.Dl Building ${.TARGET:H:tA}/${.TARGET:T} 963.It Va .MAKEOVERRIDES 964This variable is used to record the names of variables assigned to 965on the command line, so that they may be exported as part of 966.Ql Ev MAKEFLAGS . 967This behavior can be disabled by assigning an empty value to 968.Ql Va .MAKEOVERRIDES 969within a makefile. 970Extra variables can be exported from a makefile 971by appending their names to 972.Ql Va .MAKEOVERRIDES . 973.Ql Ev MAKEFLAGS 974is re-exported whenever 975.Ql Va .MAKEOVERRIDES 976is modified. 977.It Va .MAKE.PATH_FILEMON 978If 979.Nm 980was built with 981.Xr filemon 4 982support, this is set to the path of the device node. 983This allows makefiles to test for this support. 984.It Va .MAKE.PID 985The process-id of 986.Nm . 987.It Va .MAKE.PPID 988The parent process-id of 989.Nm . 990.It Va .MAKE.SAVE_DOLLARS 991value should be a boolean that controls whether 992.Ql $$ 993are preserved when doing 994.Ql := 995assignments. 996The default is true, for compatibility with other makes. 997If set to false, 998.Ql $$ 999becomes 1000.Ql $ 1001per normal evaluation rules. 1002.It Va MAKE_PRINT_VAR_ON_ERROR 1003When 1004.Nm 1005stops due to an error, it sets 1006.Ql Va .ERROR_TARGET 1007to the name of the target that failed, 1008.Ql Va .ERROR_CMD 1009to the commands of the failed target, 1010and in "meta" mode, it also sets 1011.Ql Va .ERROR_CWD 1012to the 1013.Xr getcwd 3 , 1014and 1015.Ql Va .ERROR_META_FILE 1016to the path of the meta file (if any) describing the failed target. 1017It then prints its name and the value of 1018.Ql Va .CURDIR 1019as well as the value of any variables named in 1020.Ql Va MAKE_PRINT_VAR_ON_ERROR . 1021.It Va .newline 1022This variable is simply assigned a newline character as its value. 1023This allows expansions using the 1024.Cm \&:@ 1025modifier to put a newline between 1026iterations of the loop rather than a space. 1027For example, the printing of 1028.Ql Va MAKE_PRINT_VAR_ON_ERROR 1029could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}. 1030.It Va .OBJDIR 1031A path to the directory where the targets are built. 1032Its value is determined by trying to 1033.Xr chdir 2 1034to the following directories in order and using the first match: 1035.Bl -enum 1036.It 1037.Ev ${MAKEOBJDIRPREFIX}${.CURDIR} 1038.Pp 1039(Only if 1040.Ql Ev MAKEOBJDIRPREFIX 1041is set in the environment or on the command line.) 1042.It 1043.Ev ${MAKEOBJDIR} 1044.Pp 1045(Only if 1046.Ql Ev MAKEOBJDIR 1047is set in the environment or on the command line.) 1048.It 1049.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE} 1050.It 1051.Ev ${.CURDIR} Ns Pa /obj 1052.It 1053.Pa /usr/obj/ Ns Ev ${.CURDIR} 1054.It 1055.Ev ${.CURDIR} 1056.El 1057.Pp 1058Variable expansion is performed on the value before it's used, 1059so expressions such as 1060.Dl ${.CURDIR:S,^/usr/src,/var/obj,} 1061may be used. 1062This is especially useful with 1063.Ql Ev MAKEOBJDIR . 1064.Pp 1065.Ql Va .OBJDIR 1066may be modified in the makefile via the special target 1067.Ql Ic .OBJDIR . 1068In all cases, 1069.Nm 1070will 1071.Xr chdir 2 1072to the specified directory if it exists, and set 1073.Ql Va .OBJDIR 1074and 1075.Ql Ev PWD 1076to that directory before executing any targets. 1077. 1078.It Va .PARSEDIR 1079A path to the directory of the current 1080.Ql Pa Makefile 1081being parsed. 1082.It Va .PARSEFILE 1083The basename of the current 1084.Ql Pa Makefile 1085being parsed. 1086This variable and 1087.Ql Va .PARSEDIR 1088are both set only while the 1089.Ql Pa Makefiles 1090are being parsed. 1091If you want to retain their current values, assign them to a variable 1092using assignment with expansion: 1093.Pq Ql Cm \&:= . 1094.It Va .PATH 1095A variable that represents the list of directories that 1096.Nm 1097will search for files. 1098The search list should be updated using the target 1099.Ql Va .PATH 1100rather than the variable. 1101.It Ev PWD 1102Alternate path to the current directory. 1103.Nm 1104normally sets 1105.Ql Va .CURDIR 1106to the canonical path given by 1107.Xr getcwd 3 . 1108However, if the environment variable 1109.Ql Ev PWD 1110is set and gives a path to the current directory, then 1111.Nm 1112sets 1113.Ql Va .CURDIR 1114to the value of 1115.Ql Ev PWD 1116instead. 1117This behavior is disabled if 1118.Ql Ev MAKEOBJDIRPREFIX 1119is set or 1120.Ql Ev MAKEOBJDIR 1121contains a variable transform. 1122.Ql Ev PWD 1123is set to the value of 1124.Ql Va .OBJDIR 1125for all programs which 1126.Nm 1127executes. 1128.It Ev .TARGETS 1129The list of targets explicitly specified on the command line, if any. 1130.It Ev VPATH 1131Colon-separated 1132.Pq Dq \&: 1133lists of directories that 1134.Nm 1135will search for files. 1136The variable is supported for compatibility with old make programs only, 1137use 1138.Ql Va .PATH 1139instead. 1140.El 1141.Ss Variable modifiers 1142Variable expansion may be modified to select or modify each word of the 1143variable (where a 1144.Dq word 1145is white-space delimited sequence of characters). 1146The general format of a variable expansion is as follows: 1147.Pp 1148.Dl ${variable[:modifier[:...]]} 1149.Pp 1150Each modifier begins with a colon, 1151which may be escaped with a backslash 1152.Pq Ql \e . 1153.Pp 1154A set of modifiers can be specified via a variable, as follows: 1155.Pp 1156.Dl modifier_variable=modifier[:...] 1157.Dl ${variable:${modifier_variable}[:...]} 1158.Pp 1159In this case the first modifier in the modifier_variable does not 1160start with a colon, since that must appear in the referencing 1161variable. 1162If any of the modifiers in the modifier_variable contain a dollar sign 1163.Pq Ql $ , 1164these must be doubled to avoid early expansion. 1165.Pp 1166The supported modifiers are: 1167.Bl -tag -width EEE 1168.It Cm \&:E 1169Replaces each word in the variable with its suffix. 1170.It Cm \&:H 1171Replaces each word in the variable with everything but the last component. 1172.It Cm \&:M Ns Ar pattern 1173Select only those words that match 1174.Ar pattern . 1175The standard shell wildcard characters 1176.Pf ( Ql * , 1177.Ql \&? , 1178and 1179.Ql Oo Oc ) 1180may 1181be used. 1182The wildcard characters may be escaped with a backslash 1183.Pq Ql \e . 1184As a consequence of the way values are split into words, matched, 1185and then joined, a construct like 1186.Dl ${VAR:M*} 1187will normalize the inter-word spacing, removing all leading and 1188trailing space, and converting multiple consecutive spaces 1189to single spaces. 1190. 1191.It Cm \&:N Ns Ar pattern 1192This is identical to 1193.Ql Cm \&:M , 1194but selects all words which do not match 1195.Ar pattern . 1196.It Cm \&:O 1197Order every word in variable alphabetically. 1198.It Cm \&:Or 1199Order every word in variable in reverse alphabetical order. 1200.It Cm \&:Ox 1201Randomize words in variable. 1202The results will be different each time you are referring to the 1203modified variable; use the assignment with expansion 1204.Pq Ql Cm \&:= 1205to prevent such behavior. 1206For example, 1207.Bd -literal -offset indent 1208LIST= uno due tre quattro 1209RANDOM_LIST= ${LIST:Ox} 1210STATIC_RANDOM_LIST:= ${LIST:Ox} 1211 1212all: 1213 @echo "${RANDOM_LIST}" 1214 @echo "${RANDOM_LIST}" 1215 @echo "${STATIC_RANDOM_LIST}" 1216 @echo "${STATIC_RANDOM_LIST}" 1217.Ed 1218may produce output similar to: 1219.Bd -literal -offset indent 1220quattro due tre uno 1221tre due quattro uno 1222due uno quattro tre 1223due uno quattro tre 1224.Ed 1225.It Cm \&:Q 1226Quotes every shell meta-character in the variable, so that it can be passed 1227safely to the shell. 1228.It Cm \&:q 1229Quotes every shell meta-character in the variable, and also doubles 1230.Sq $ 1231characters so that it can be passed 1232safely through recursive invocations of 1233.Nm . 1234This is equivalent to: 1235.Sq \&:S/\e\&$/&&/g:Q . 1236.It Cm \&:R 1237Replaces each word in the variable with everything but its suffix. 1238.It Cm \&:range[=count] 1239The value is an integer sequence representing the words of the original 1240value, or the supplied 1241.Va count . 1242.It Cm \&:gmtime[=utc] 1243The value is a format string for 1244.Xr strftime 3 , 1245using 1246.Xr gmtime 3 . 1247If a 1248.Va utc 1249value is not provided or is 0, the current time is used. 1250.It Cm \&:hash 1251Compute a 32-bit hash of the value and encode it as hex digits. 1252.It Cm \&:localtime[=utc] 1253The value is a format string for 1254.Xr strftime 3 , 1255using 1256.Xr localtime 3 . 1257If a 1258.Va utc 1259value is not provided or is 0, the current time is used. 1260.It Cm \&:tA 1261Attempt to convert variable to an absolute path using 1262.Xr realpath 3 , 1263if that fails, the value is unchanged. 1264.It Cm \&:tl 1265Converts variable to lower-case letters. 1266.It Cm \&:ts Ns Ar c 1267Words in the variable are normally separated by a space on expansion. 1268This modifier sets the separator to the character 1269.Ar c . 1270If 1271.Ar c 1272is omitted, then no separator is used. 1273The common escapes (including octal numeric codes), work as expected. 1274.It Cm \&:tu 1275Converts variable to upper-case letters. 1276.It Cm \&:tW 1277Causes the value to be treated as a single word 1278(possibly containing embedded white space). 1279See also 1280.Ql Cm \&:[*] . 1281.It Cm \&:tw 1282Causes the value to be treated as a sequence of 1283words delimited by white space. 1284See also 1285.Ql Cm \&:[@] . 1286.Sm off 1287.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW 1288.Sm on 1289Modify the first occurrence of 1290.Ar old_string 1291in the variable's value, replacing it with 1292.Ar new_string . 1293If a 1294.Ql g 1295is appended to the last slash of the pattern, all occurrences 1296in each word are replaced. 1297If a 1298.Ql 1 1299is appended to the last slash of the pattern, only the first word 1300is affected. 1301If a 1302.Ql W 1303is appended to the last slash of the pattern, 1304then the value is treated as a single word 1305(possibly containing embedded white space). 1306If 1307.Ar old_string 1308begins with a caret 1309.Pq Ql ^ , 1310.Ar old_string 1311is anchored at the beginning of each word. 1312If 1313.Ar old_string 1314ends with a dollar sign 1315.Pq Ql \&$ , 1316it is anchored at the end of each word. 1317Inside 1318.Ar new_string , 1319an ampersand 1320.Pq Ql & 1321is replaced by 1322.Ar old_string 1323(without any 1324.Ql ^ 1325or 1326.Ql \&$ ) . 1327Any character may be used as a delimiter for the parts of the modifier 1328string. 1329The anchoring, ampersand and delimiter characters may be escaped with a 1330backslash 1331.Pq Ql \e . 1332.Pp 1333Variable expansion occurs in the normal fashion inside both 1334.Ar old_string 1335and 1336.Ar new_string 1337with the single exception that a backslash is used to prevent the expansion 1338of a dollar sign 1339.Pq Ql \&$ , 1340not a preceding dollar sign as is usual. 1341.Sm off 1342.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW 1343.Sm on 1344The 1345.Cm \&:C 1346modifier is just like the 1347.Cm \&:S 1348modifier except that the old and new strings, instead of being 1349simple strings, are an extended regular expression (see 1350.Xr regex 3 ) 1351string 1352.Ar pattern 1353and an 1354.Xr ed 1 Ns \-style 1355string 1356.Ar replacement . 1357Normally, the first occurrence of the pattern 1358.Ar pattern 1359in each word of the value is substituted with 1360.Ar replacement . 1361The 1362.Ql 1 1363modifier causes the substitution to apply to at most one word; the 1364.Ql g 1365modifier causes the substitution to apply to as many instances of the 1366search pattern 1367.Ar pattern 1368as occur in the word or words it is found in; the 1369.Ql W 1370modifier causes the value to be treated as a single word 1371(possibly containing embedded white space). 1372Note that 1373.Ql 1 1374and 1375.Ql g 1376are orthogonal; the former specifies whether multiple words are 1377potentially affected, the latter whether multiple substitutions can 1378potentially occur within each affected word. 1379.Pp 1380As for the 1381.Cm \&:S 1382modifier, the 1383.Ar pattern 1384and 1385.Ar replacement 1386are subjected to variable expansion before being parsed as 1387regular expressions. 1388.It Cm \&:T 1389Replaces each word in the variable with its last component. 1390.It Cm \&:u 1391Remove adjacent duplicate words (like 1392.Xr uniq 1 ) . 1393.Sm off 1394.It Cm \&:\&? Ar true_string Cm \&: Ar false_string 1395.Sm on 1396If the variable name (not its value), when parsed as a .if conditional 1397expression, evaluates to true, return as its value the 1398.Ar true_string , 1399otherwise return the 1400.Ar false_string . 1401Since the variable name is used as the expression, \&:\&? must be the 1402first modifier after the variable name itself - which will, of course, 1403usually contain variable expansions. 1404A common error is trying to use expressions like 1405.Dl ${NUMBERS:M42:?match:no} 1406which actually tests defined(NUMBERS), 1407to determine is any words match "42" you need to use something like: 1408.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} . 1409.It Ar :old_string=new_string 1410This is the 1411.At V 1412style variable substitution. 1413It must be the last modifier specified. 1414If 1415.Ar old_string 1416or 1417.Ar new_string 1418do not contain the pattern matching character 1419.Ar % 1420then it is assumed that they are 1421anchored at the end of each word, so only suffixes or entire 1422words may be replaced. 1423Otherwise 1424.Ar % 1425is the substring of 1426.Ar old_string 1427to be replaced in 1428.Ar new_string . 1429If only 1430.Ar old_string 1431contains the pattern matching character 1432.Ar % , 1433and 1434.Ar old_string 1435matches, then the result is the 1436.Ar new_string . 1437If only the 1438.Ar new_string 1439contains the pattern matching character 1440.Ar % , 1441then it is not treated specially and it is printed as a literal 1442.Ar % 1443on match. 1444If there is more than one pattern matching character 1445.Ar ( % ) 1446in either the 1447.Ar new_string 1448or 1449.Ar old_string , 1450only the first instance is treated specially (as the pattern character); 1451all subsequent instances are treated as regular characters 1452.Pp 1453Variable expansion occurs in the normal fashion inside both 1454.Ar old_string 1455and 1456.Ar new_string 1457with the single exception that a backslash is used to prevent the 1458expansion of a dollar sign 1459.Pq Ql \&$ , 1460not a preceding dollar sign as is usual. 1461.Sm off 1462.It Cm \&:@ Ar temp Cm @ Ar string Cm @ 1463.Sm on 1464This is the loop expansion mechanism from the OSF Development 1465Environment (ODE) make. 1466Unlike 1467.Cm \&.for 1468loops expansion occurs at the time of 1469reference. 1470Assign 1471.Ar temp 1472to each word in the variable and evaluate 1473.Ar string . 1474The ODE convention is that 1475.Ar temp 1476should start and end with a period. 1477For example. 1478.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@} 1479.Pp 1480However a single character variable is often more readable: 1481.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@} 1482.It Cm \&:_[=var] 1483Save the current variable value in 1484.Ql $_ 1485or the named 1486.Va var 1487for later reference. 1488Example usage: 1489.Bd -literal -offset indent 1490M_cmpv.units = 1 1000 1000000 1491M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\ 1492\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh 1493 1494.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}} 1495 1496.Ed 1497Here 1498.Ql $_ 1499is used to save the result of the 1500.Ql :S 1501modifier which is later referenced using the index values from 1502.Ql :range . 1503.It Cm \&:U Ns Ar newval 1504If the variable is undefined 1505.Ar newval 1506is the value. 1507If the variable is defined, the existing value is returned. 1508This is another ODE make feature. 1509It is handy for setting per-target CFLAGS for instance: 1510.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}} 1511If a value is only required if the variable is undefined, use: 1512.Dl ${VAR:D:Unewval} 1513.It Cm \&:D Ns Ar newval 1514If the variable is defined 1515.Ar newval 1516is the value. 1517.It Cm \&:L 1518The name of the variable is the value. 1519.It Cm \&:P 1520The path of the node which has the same name as the variable 1521is the value. 1522If no such node exists or its path is null, then the 1523name of the variable is used. 1524In order for this modifier to work, the name (node) must at least have 1525appeared on the rhs of a dependency. 1526.Sm off 1527.It Cm \&:\&! Ar cmd Cm \&! 1528.Sm on 1529The output of running 1530.Ar cmd 1531is the value. 1532.It Cm \&:sh 1533If the variable is non-empty it is run as a command and the output 1534becomes the new value. 1535.It Cm \&::= Ns Ar str 1536The variable is assigned the value 1537.Ar str 1538after substitution. 1539This modifier and its variations are useful in 1540obscure situations such as wanting to set a variable when shell commands 1541are being parsed. 1542These assignment modifiers always expand to 1543nothing, so if appearing in a rule line by themselves should be 1544preceded with something to keep 1545.Nm 1546happy. 1547.Pp 1548The 1549.Ql Cm \&:: 1550helps avoid false matches with the 1551.At V 1552style 1553.Cm \&:= 1554modifier and since substitution always occurs the 1555.Cm \&::= 1556form is vaguely appropriate. 1557.It Cm \&::?= Ns Ar str 1558As for 1559.Cm \&::= 1560but only if the variable does not already have a value. 1561.It Cm \&::+= Ns Ar str 1562Append 1563.Ar str 1564to the variable. 1565.It Cm \&::!= Ns Ar cmd 1566Assign the output of 1567.Ar cmd 1568to the variable. 1569.It Cm \&:\&[ Ns Ar range Ns Cm \&] 1570Selects one or more words from the value, 1571or performs other operations related to the way in which the 1572value is divided into words. 1573.Pp 1574Ordinarily, a value is treated as a sequence of words 1575delimited by white space. 1576Some modifiers suppress this behavior, 1577causing a value to be treated as a single word 1578(possibly containing embedded white space). 1579An empty value, or a value that consists entirely of white-space, 1580is treated as a single word. 1581For the purposes of the 1582.Ql Cm \&:[] 1583modifier, the words are indexed both forwards using positive integers 1584(where index 1 represents the first word), 1585and backwards using negative integers 1586(where index \-1 represents the last word). 1587.Pp 1588The 1589.Ar range 1590is subjected to variable expansion, and the expanded result is 1591then interpreted as follows: 1592.Bl -tag -width index 1593.\" :[n] 1594.It Ar index 1595Selects a single word from the value. 1596.\" :[start..end] 1597.It Ar start Ns Cm \&.. Ns Ar end 1598Selects all words from 1599.Ar start 1600to 1601.Ar end , 1602inclusive. 1603For example, 1604.Ql Cm \&:[2..-1] 1605selects all words from the second word to the last word. 1606If 1607.Ar start 1608is greater than 1609.Ar end , 1610then the words are output in reverse order. 1611For example, 1612.Ql Cm \&:[-1..1] 1613selects all the words from last to first. 1614If the list is already ordered, then this effectively reverses 1615the list, but it is more efficient to use 1616.Ql Cm \&:Or 1617instead of 1618.Ql Cm \&:O:[-1..1] . 1619.\" :[*] 1620.It Cm \&* 1621Causes subsequent modifiers to treat the value as a single word 1622(possibly containing embedded white space). 1623Analogous to the effect of 1624\&"$*\&" 1625in Bourne shell. 1626.\" :[0] 1627.It 0 1628Means the same as 1629.Ql Cm \&:[*] . 1630.\" :[*] 1631.It Cm \&@ 1632Causes subsequent modifiers to treat the value as a sequence of words 1633delimited by white space. 1634Analogous to the effect of 1635\&"$@\&" 1636in Bourne shell. 1637.\" :[#] 1638.It Cm \&# 1639Returns the number of words in the value. 1640.El \" :[range] 1641.El 1642.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS 1643Makefile inclusion, conditional structures and for loops reminiscent 1644of the C programming language are provided in 1645.Nm . 1646All such structures are identified by a line beginning with a single 1647dot 1648.Pq Ql \&. 1649character. 1650Files are included with either 1651.Cm \&.include \&< Ns Ar file Ns Cm \&> 1652or 1653.Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q . 1654Variables between the angle brackets or double quotes are expanded 1655to form the file name. 1656If angle brackets are used, the included makefile is expected to be in 1657the system makefile directory. 1658If double quotes are used, the including makefile's directory and any 1659directories specified using the 1660.Fl I 1661option are searched before the system 1662makefile directory. 1663For compatibility with other versions of 1664.Nm 1665.Ql include file ... 1666is also accepted. 1667.Pp 1668If the include statement is written as 1669.Cm .-include 1670or as 1671.Cm .sinclude 1672then errors locating and/or opening include files are ignored. 1673.Pp 1674If the include statement is written as 1675.Cm .dinclude 1676not only are errors locating and/or opening include files ignored, 1677but stale dependencies within the included file will be ignored 1678just like 1679.Va .MAKE.DEPENDFILE . 1680.Pp 1681Conditional expressions are also preceded by a single dot as the first 1682character of a line. 1683The possible conditionals are as follows: 1684.Bl -tag -width Ds 1685.It Ic .error Ar message 1686The message is printed along with the name of the makefile and line number, 1687then 1688.Nm 1689will exit. 1690.It Ic .export Ar variable ... 1691Export the specified global variable. 1692If no variable list is provided, all globals are exported 1693except for internal variables (those that start with 1694.Ql \&. ) . 1695This is not affected by the 1696.Fl X 1697flag, so should be used with caution. 1698For compatibility with other 1699.Nm 1700programs 1701.Ql export variable=value 1702is also accepted. 1703.Pp 1704Appending a variable name to 1705.Va .MAKE.EXPORTED 1706is equivalent to exporting a variable. 1707.It Ic .export-env Ar variable ... 1708The same as 1709.Ql .export , 1710except that the variable is not appended to 1711.Va .MAKE.EXPORTED . 1712This allows exporting a value to the environment which is different from that 1713used by 1714.Nm 1715internally. 1716.It Ic .export-literal Ar variable ... 1717The same as 1718.Ql .export-env , 1719except that variables in the value are not expanded. 1720.It Ic .info Ar message 1721The message is printed along with the name of the makefile and line number. 1722.It Ic .undef Ar variable 1723Un-define the specified global variable. 1724Only global variables may be un-defined. 1725.It Ic .unexport Ar variable ... 1726The opposite of 1727.Ql .export . 1728The specified global 1729.Va variable 1730will be removed from 1731.Va .MAKE.EXPORTED . 1732If no variable list is provided, all globals are unexported, 1733and 1734.Va .MAKE.EXPORTED 1735deleted. 1736.It Ic .unexport-env 1737Unexport all globals previously exported and 1738clear the environment inherited from the parent. 1739This operation will cause a memory leak of the original environment, 1740so should be used sparingly. 1741Testing for 1742.Va .MAKE.LEVEL 1743being 0, would make sense. 1744Also note that any variables which originated in the parent environment 1745should be explicitly preserved if desired. 1746For example: 1747.Bd -literal -offset indent 1748.Li .if ${.MAKE.LEVEL} == 0 1749PATH := ${PATH} 1750.Li .unexport-env 1751.Li .export PATH 1752.Li .endif 1753.Pp 1754.Ed 1755Would result in an environment containing only 1756.Ql Ev PATH , 1757which is the minimal useful environment. 1758Actually 1759.Ql Ev .MAKE.LEVEL 1760will also be pushed into the new environment. 1761.It Ic .warning Ar message 1762The message prefixed by 1763.Ql Pa warning: 1764is printed along with the name of the makefile and line number. 1765.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ... 1766Test the value of an expression. 1767.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1768Test the value of a variable. 1769.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1770Test the value of a variable. 1771.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1772Test the target being built. 1773.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ... 1774Test the target being built. 1775.It Ic .else 1776Reverse the sense of the last conditional. 1777.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ... 1778A combination of 1779.Ql Ic .else 1780followed by 1781.Ql Ic .if . 1782.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1783A combination of 1784.Ql Ic .else 1785followed by 1786.Ql Ic .ifdef . 1787.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1788A combination of 1789.Ql Ic .else 1790followed by 1791.Ql Ic .ifndef . 1792.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1793A combination of 1794.Ql Ic .else 1795followed by 1796.Ql Ic .ifmake . 1797.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1798A combination of 1799.Ql Ic .else 1800followed by 1801.Ql Ic .ifnmake . 1802.It Ic .endif 1803End the body of the conditional. 1804.El 1805.Pp 1806The 1807.Ar operator 1808may be any one of the following: 1809.Bl -tag -width "Cm XX" 1810.It Cm \&|\&| 1811Logical OR. 1812.It Cm \&&& 1813Logical 1814.Tn AND ; 1815of higher precedence than 1816.Dq \&|\&| . 1817.El 1818.Pp 1819As in C, 1820.Nm 1821will only evaluate a conditional as far as is necessary to determine 1822its value. 1823Parentheses may be used to change the order of evaluation. 1824The boolean operator 1825.Ql Ic \&! 1826may be used to logically negate an entire 1827conditional. 1828It is of higher precedence than 1829.Ql Ic \&&& . 1830.Pp 1831The value of 1832.Ar expression 1833may be any of the following: 1834.Bl -tag -width defined 1835.It Ic defined 1836Takes a variable name as an argument and evaluates to true if the variable 1837has been defined. 1838.It Ic make 1839Takes a target name as an argument and evaluates to true if the target 1840was specified as part of 1841.Nm Ns 's 1842command line or was declared the default target (either implicitly or 1843explicitly, see 1844.Va .MAIN ) 1845before the line containing the conditional. 1846.It Ic empty 1847Takes a variable, with possible modifiers, and evaluates to true if 1848the expansion of the variable would result in an empty string. 1849.It Ic exists 1850Takes a file name as an argument and evaluates to true if the file exists. 1851The file is searched for on the system search path (see 1852.Va .PATH ) . 1853.It Ic target 1854Takes a target name as an argument and evaluates to true if the target 1855has been defined. 1856.It Ic commands 1857Takes a target name as an argument and evaluates to true if the target 1858has been defined and has commands associated with it. 1859.El 1860.Pp 1861.Ar Expression 1862may also be an arithmetic or string comparison. 1863Variable expansion is 1864performed on both sides of the comparison, after which the integral 1865values are compared. 1866A value is interpreted as hexadecimal if it is 1867preceded by 0x, otherwise it is decimal; octal numbers are not supported. 1868The standard C relational operators are all supported. 1869If after 1870variable expansion, either the left or right hand side of a 1871.Ql Ic == 1872or 1873.Ql Ic "!=" 1874operator is not an integral value, then 1875string comparison is performed between the expanded 1876variables. 1877If no relational operator is given, it is assumed that the expanded 1878variable is being compared against 0 or an empty string in the case 1879of a string comparison. 1880.Pp 1881When 1882.Nm 1883is evaluating one of these conditional expressions, and it encounters 1884a (white-space separated) word it doesn't recognize, either the 1885.Dq make 1886or 1887.Dq defined 1888expression is applied to it, depending on the form of the conditional. 1889If the form is 1890.Ql Ic .ifdef , 1891.Ql Ic .ifndef , 1892or 1893.Ql Ic .if 1894the 1895.Dq defined 1896expression is applied. 1897Similarly, if the form is 1898.Ql Ic .ifmake 1899or 1900.Ql Ic .ifnmake , 1901the 1902.Dq make 1903expression is applied. 1904.Pp 1905If the conditional evaluates to true the parsing of the makefile continues 1906as before. 1907If it evaluates to false, the following lines are skipped. 1908In both cases this continues until a 1909.Ql Ic .else 1910or 1911.Ql Ic .endif 1912is found. 1913.Pp 1914For loops are typically used to apply a set of rules to a list of files. 1915The syntax of a for loop is: 1916.Pp 1917.Bl -tag -compact -width Ds 1918.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression 1919.It Aq make-rules 1920.It Ic \&.endfor 1921.El 1922.Pp 1923After the for 1924.Ic expression 1925is evaluated, it is split into words. 1926On each iteration of the loop, one word is taken and assigned to each 1927.Ic variable , 1928in order, and these 1929.Ic variables 1930are substituted into the 1931.Ic make-rules 1932inside the body of the for loop. 1933The number of words must come out even; that is, if there are three 1934iteration variables, the number of words provided must be a multiple 1935of three. 1936.Sh COMMENTS 1937Comments begin with a hash 1938.Pq Ql \&# 1939character, anywhere but in a shell 1940command line, and continue to the end of an unescaped new line. 1941.Sh SPECIAL SOURCES (ATTRIBUTES) 1942.Bl -tag -width .IGNOREx 1943.It Ic .EXEC 1944Target is never out of date, but always execute commands anyway. 1945.It Ic .IGNORE 1946Ignore any errors from the commands associated with this target, exactly 1947as if they all were preceded by a dash 1948.Pq Ql \- . 1949.\" .It Ic .INVISIBLE 1950.\" XXX 1951.\" .It Ic .JOIN 1952.\" XXX 1953.It Ic .MADE 1954Mark all sources of this target as being up-to-date. 1955.It Ic .MAKE 1956Execute the commands associated with this target even if the 1957.Fl n 1958or 1959.Fl t 1960options were specified. 1961Normally used to mark recursive 1962.Nm Ns s . 1963.It Ic .META 1964Create a meta file for the target, even if it is flagged as 1965.Ic .PHONY , 1966.Ic .MAKE , 1967or 1968.Ic .SPECIAL . 1969Usage in conjunction with 1970.Ic .MAKE 1971is the most likely case. 1972In "meta" mode, the target is out-of-date if the meta file is missing. 1973.It Ic .NOMETA 1974Do not create a meta file for the target. 1975Meta files are also not created for 1976.Ic .PHONY , 1977.Ic .MAKE , 1978or 1979.Ic .SPECIAL 1980targets. 1981.It Ic .NOMETA_CMP 1982Ignore differences in commands when deciding if target is out of date. 1983This is useful if the command contains a value which always changes. 1984If the number of commands change, though, the target will still be out of date. 1985The same effect applies to any command line that uses the variable 1986.Va .OODATE , 1987which can be used for that purpose even when not otherwise needed or desired: 1988.Bd -literal -offset indent 1989 1990skip-compare-for-some: 1991 @echo this will be compared 1992 @echo this will not ${.OODATE:M.NOMETA_CMP} 1993 @echo this will also be compared 1994 1995.Ed 1996The 1997.Cm \&:M 1998pattern suppresses any expansion of the unwanted variable. 1999.It Ic .NOPATH 2000Do not search for the target in the directories specified by 2001.Ic .PATH . 2002.It Ic .NOTMAIN 2003Normally 2004.Nm 2005selects the first target it encounters as the default target to be built 2006if no target was specified. 2007This source prevents this target from being selected. 2008.It Ic .OPTIONAL 2009If a target is marked with this attribute and 2010.Nm 2011can't figure out how to create it, it will ignore this fact and assume 2012the file isn't needed or already exists. 2013.It Ic .PHONY 2014The target does not 2015correspond to an actual file; it is always considered to be out of date, 2016and will not be created with the 2017.Fl t 2018option. 2019Suffix-transformation rules are not applied to 2020.Ic .PHONY 2021targets. 2022.It Ic .PRECIOUS 2023When 2024.Nm 2025is interrupted, it normally removes any partially made targets. 2026This source prevents the target from being removed. 2027.It Ic .RECURSIVE 2028Synonym for 2029.Ic .MAKE . 2030.It Ic .SILENT 2031Do not echo any of the commands associated with this target, exactly 2032as if they all were preceded by an at sign 2033.Pq Ql @ . 2034.It Ic .USE 2035Turn the target into 2036.Nm Ns 's 2037version of a macro. 2038When the target is used as a source for another target, the other target 2039acquires the commands, sources, and attributes (except for 2040.Ic .USE ) 2041of the 2042source. 2043If the target already has commands, the 2044.Ic .USE 2045target's commands are appended 2046to them. 2047.It Ic .USEBEFORE 2048Exactly like 2049.Ic .USE , 2050but prepend the 2051.Ic .USEBEFORE 2052target commands to the target. 2053.It Ic .WAIT 2054If 2055.Ic .WAIT 2056appears in a dependency line, the sources that precede it are 2057made before the sources that succeed it in the line. 2058Since the dependents of files are not made until the file itself 2059could be made, this also stops the dependents being built unless they 2060are needed for another branch of the dependency tree. 2061So given: 2062.Bd -literal 2063x: a .WAIT b 2064 echo x 2065a: 2066 echo a 2067b: b1 2068 echo b 2069b1: 2070 echo b1 2071 2072.Ed 2073the output is always 2074.Ql a , 2075.Ql b1 , 2076.Ql b , 2077.Ql x . 2078.br 2079The ordering imposed by 2080.Ic .WAIT 2081is only relevant for parallel makes. 2082.El 2083.Sh SPECIAL TARGETS 2084Special targets may not be included with other targets, i.e. they must be 2085the only target specified. 2086.Bl -tag -width .BEGINx 2087.It Ic .BEGIN 2088Any command lines attached to this target are executed before anything 2089else is done. 2090.It Ic .DEFAULT 2091This is sort of a 2092.Ic .USE 2093rule for any target (that was used only as a 2094source) that 2095.Nm 2096can't figure out any other way to create. 2097Only the shell script is used. 2098The 2099.Ic .IMPSRC 2100variable of a target that inherits 2101.Ic .DEFAULT Ns 's 2102commands is set 2103to the target's own name. 2104.It Ic .DELETE_ON_ERROR 2105If this target is present in the makefile, it globally causes make to 2106delete targets whose commands fail. 2107(By default, only targets whose commands are interrupted during 2108execution are deleted. 2109This is the historical behavior.) 2110This setting can be used to help prevent half-finished or malformed 2111targets from being left around and corrupting future rebuilds. 2112.It Ic .END 2113Any command lines attached to this target are executed after everything 2114else is done. 2115.It Ic .ERROR 2116Any command lines attached to this target are executed when another target fails. 2117The 2118.Ic .ERROR_TARGET 2119variable is set to the target that failed. 2120See also 2121.Ic MAKE_PRINT_VAR_ON_ERROR . 2122.It Ic .IGNORE 2123Mark each of the sources with the 2124.Ic .IGNORE 2125attribute. 2126If no sources are specified, this is the equivalent of specifying the 2127.Fl i 2128option. 2129.It Ic .INTERRUPT 2130If 2131.Nm 2132is interrupted, the commands for this target will be executed. 2133.It Ic .MAIN 2134If no target is specified when 2135.Nm 2136is invoked, this target will be built. 2137.It Ic .MAKEFLAGS 2138This target provides a way to specify flags for 2139.Nm 2140when the makefile is used. 2141The flags are as if typed to the shell, though the 2142.Fl f 2143option will have 2144no effect. 2145.\" XXX: NOT YET!!!! 2146.\" .It Ic .NOTPARALLEL 2147.\" The named targets are executed in non parallel mode. 2148.\" If no targets are 2149.\" specified, then all targets are executed in non parallel mode. 2150.It Ic .NOPATH 2151Apply the 2152.Ic .NOPATH 2153attribute to any specified sources. 2154.It Ic .NOTPARALLEL 2155Disable parallel mode. 2156.It Ic .NO_PARALLEL 2157Synonym for 2158.Ic .NOTPARALLEL , 2159for compatibility with other pmake variants. 2160.It Ic .OBJDIR 2161The source is a new value for 2162.Ql Va .OBJDIR . 2163If it exists, 2164.Nm 2165will 2166.Xr chdir 2 2167to it and update the value of 2168.Ql Va .OBJDIR . 2169.It Ic .ORDER 2170The named targets are made in sequence. 2171This ordering does not add targets to the list of targets to be made. 2172Since the dependents of a target do not get built until the target itself 2173could be built, unless 2174.Ql a 2175is built by another part of the dependency graph, 2176the following is a dependency loop: 2177.Bd -literal 2178\&.ORDER: b a 2179b: a 2180.Ed 2181.Pp 2182The ordering imposed by 2183.Ic .ORDER 2184is only relevant for parallel makes. 2185.\" XXX: NOT YET!!!! 2186.\" .It Ic .PARALLEL 2187.\" The named targets are executed in parallel mode. 2188.\" If no targets are 2189.\" specified, then all targets are executed in parallel mode. 2190.It Ic .PATH 2191The sources are directories which are to be searched for files not 2192found in the current directory. 2193If no sources are specified, any previously specified directories are 2194deleted. 2195If the source is the special 2196.Ic .DOTLAST 2197target, then the current working 2198directory is searched last. 2199.It Ic .PATH. Ns Va suffix 2200Like 2201.Ic .PATH 2202but applies only to files with a particular suffix. 2203The suffix must have been previously declared with 2204.Ic .SUFFIXES . 2205.It Ic .PHONY 2206Apply the 2207.Ic .PHONY 2208attribute to any specified sources. 2209.It Ic .PRECIOUS 2210Apply the 2211.Ic .PRECIOUS 2212attribute to any specified sources. 2213If no sources are specified, the 2214.Ic .PRECIOUS 2215attribute is applied to every 2216target in the file. 2217.It Ic .SHELL 2218Sets the shell that 2219.Nm 2220will use to execute commands. 2221The sources are a set of 2222.Ar field=value 2223pairs. 2224.Bl -tag -width hasErrCtls 2225.It Ar name 2226This is the minimal specification, used to select one of the built-in 2227shell specs; 2228.Ar sh , 2229.Ar ksh , 2230and 2231.Ar csh . 2232.It Ar path 2233Specifies the path to the shell. 2234.It Ar hasErrCtl 2235Indicates whether the shell supports exit on error. 2236.It Ar check 2237The command to turn on error checking. 2238.It Ar ignore 2239The command to disable error checking. 2240.It Ar echo 2241The command to turn on echoing of commands executed. 2242.It Ar quiet 2243The command to turn off echoing of commands executed. 2244.It Ar filter 2245The output to filter after issuing the 2246.Ar quiet 2247command. 2248It is typically identical to 2249.Ar quiet . 2250.It Ar errFlag 2251The flag to pass the shell to enable error checking. 2252.It Ar echoFlag 2253The flag to pass the shell to enable command echoing. 2254.It Ar newline 2255The string literal to pass the shell that results in a single newline 2256character when used outside of any quoting characters. 2257.El 2258Example: 2259.Bd -literal 2260\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e 2261 check="set \-e" ignore="set +e" \e 2262 echo="set \-v" quiet="set +v" filter="set +v" \e 2263 echoFlag=v errFlag=e newline="'\en'" 2264.Ed 2265.It Ic .SILENT 2266Apply the 2267.Ic .SILENT 2268attribute to any specified sources. 2269If no sources are specified, the 2270.Ic .SILENT 2271attribute is applied to every 2272command in the file. 2273.It Ic .STALE 2274This target gets run when a dependency file contains stale entries, having 2275.Va .ALLSRC 2276set to the name of that dependency file. 2277.It Ic .SUFFIXES 2278Each source specifies a suffix to 2279.Nm . 2280If no sources are specified, any previously specified suffixes are deleted. 2281It allows the creation of suffix-transformation rules. 2282.Pp 2283Example: 2284.Bd -literal 2285\&.SUFFIXES: .o 2286\&.c.o: 2287 cc \-o ${.TARGET} \-c ${.IMPSRC} 2288.Ed 2289.El 2290.Sh ENVIRONMENT 2291.Nm 2292uses the following environment variables, if they exist: 2293.Ev MACHINE , 2294.Ev MACHINE_ARCH , 2295.Ev MAKE , 2296.Ev MAKEFLAGS , 2297.Ev MAKEOBJDIR , 2298.Ev MAKEOBJDIRPREFIX , 2299.Ev MAKESYSPATH , 2300.Ev PWD , 2301and 2302.Ev TMPDIR . 2303.Pp 2304.Ev MAKEOBJDIRPREFIX 2305and 2306.Ev MAKEOBJDIR 2307may only be set in the environment or on the command line to 2308.Nm 2309and not as makefile variables; 2310see the description of 2311.Ql Va .OBJDIR 2312for more details. 2313.Sh FILES 2314.Bl -tag -width /usr/share/mk -compact 2315.It .depend 2316list of dependencies 2317.It Makefile 2318list of dependencies 2319.It makefile 2320list of dependencies 2321.It sys.mk 2322system makefile 2323.It /usr/share/mk 2324system makefile directory 2325.El 2326.Sh COMPATIBILITY 2327The basic make syntax is compatible between different versions of make; 2328however the special variables, variable modifiers and conditionals are not. 2329.Ss Older versions 2330An incomplete list of changes in older versions of 2331.Nm : 2332.Pp 2333The way that .for loop variables are substituted changed after 2334.Nx 5.0 2335so that they still appear to be variable expansions. 2336In particular this stops them being treated as syntax, and removes some 2337obscure problems using them in .if statements. 2338.Pp 2339The way that parallel makes are scheduled changed in 2340.Nx 4.0 2341so that .ORDER and .WAIT apply recursively to the dependent nodes. 2342The algorithms used may change again in the future. 2343.Ss Other make dialects 2344Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not 2345support most of the features of 2346.Nm 2347as described in this manual. 2348Most notably: 2349.Bl -bullet -offset indent 2350.It 2351The 2352.Ic .WAIT 2353and 2354.Ic .ORDER 2355declarations and most functionality pertaining to parallelization. 2356(GNU make supports parallelization but lacks these features needed to 2357control it effectively.) 2358.It 2359Directives, including for loops and conditionals and most of the 2360forms of include files. 2361(GNU make has its own incompatible and less powerful syntax for 2362conditionals.) 2363.It 2364All built-in variables that begin with a dot. 2365.It 2366Most of the special sources and targets that begin with a dot, 2367with the notable exception of 2368.Ic .PHONY , 2369.Ic .PRECIOUS , 2370and 2371.Ic .SUFFIXES . 2372.It 2373Variable modifiers, except for the 2374.Dl :old=new 2375string substitution, which does not portably support globbing with 2376.Ql % 2377and historically only works on declared suffixes. 2378.It 2379The 2380.Ic $> 2381variable even in its short form; most makes support this functionality 2382but its name varies. 2383.El 2384.Pp 2385Some features are somewhat more portable, such as assignment with 2386.Ic += , 2387.Ic ?= , 2388and 2389.Ic != . 2390The 2391.Ic .PATH 2392functionality is based on an older feature 2393.Ic VPATH 2394found in GNU make and many versions of SVR4 make; however, 2395historically its behavior is too ill-defined (and too buggy) to rely 2396upon. 2397.Pp 2398The 2399.Ic $@ 2400and 2401.Ic $< 2402variables are more or less universally portable, as is the 2403.Ic $(MAKE) 2404variable. 2405Basic use of suffix rules (for files only in the current directory, 2406not trying to chain transformations together, etc.) is also reasonably 2407portable. 2408.Sh SEE ALSO 2409.Xr mkdep 1 2410.Sh HISTORY 2411A 2412.Nm 2413command appeared in 2414.At v7 . 2415This 2416.Nm 2417implementation is based on Adam De Boor's pmake program which was written 2418for Sprite at Berkeley. 2419It was designed to be a parallel distributed make running jobs on different 2420machines using a daemon called 2421.Dq customs . 2422.Pp 2423Historically the target/dependency 2424.Dq FRC 2425has been used to FoRCe rebuilding (since the target/dependency 2426does not exist... unless someone creates an 2427.Dq FRC 2428file). 2429.Sh BUGS 2430The 2431.Nm 2432syntax is difficult to parse without actually acting on the data. 2433For instance, finding the end of a variable's use should involve scanning 2434each of the modifiers, using the correct terminator for each field. 2435In many places 2436.Nm 2437just counts {} and () in order to find the end of a variable expansion. 2438.Pp 2439There is no way of escaping a space character in a filename. 2440