1.\" $NetBSD: make.1,v 1.280 2020/04/27 20:03:08 christos 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 April 27, 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.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 to the shell. 1242.It Cm \&:q 1243Quotes every shell meta-character in the variable, and also doubles 1244.Sq $ 1245characters so that it can be passed 1246safely through recursive invocations of 1247.Nm . 1248This is equivalent to: 1249.Sq \&:S/\e\&$/&&/g:Q . 1250.It Cm \&:R 1251Replaces each word in the variable with everything but its suffix. 1252.It Cm \&:range[=count] 1253The value is an integer sequence representing the words of the original 1254value, or the supplied 1255.Va count . 1256.It Cm \&:gmtime[=utc] 1257The value is a format string for 1258.Xr strftime 3 , 1259using 1260.Xr gmtime 3 . 1261If a 1262.Va utc 1263value is not provided or is 0, the current time is used. 1264.It Cm \&:hash 1265Compute a 32-bit hash of the value and encode it as hex digits. 1266.It Cm \&:localtime[=utc] 1267The value is a format string for 1268.Xr strftime 3 , 1269using 1270.Xr localtime 3 . 1271If a 1272.Va utc 1273value is not provided or is 0, the current time is used. 1274.It Cm \&:tA 1275Attempt to convert variable to an absolute path using 1276.Xr realpath 3 , 1277if that fails, the value is unchanged. 1278.It Cm \&:tl 1279Converts variable to lower-case letters. 1280.It Cm \&:ts Ns Ar c 1281Words in the variable are normally separated by a space on expansion. 1282This modifier sets the separator to the character 1283.Ar c . 1284If 1285.Ar c 1286is omitted, then no separator is used. 1287The common escapes (including octal numeric codes), work as expected. 1288.It Cm \&:tu 1289Converts variable to upper-case letters. 1290.It Cm \&:tW 1291Causes the value to be treated as a single word 1292(possibly containing embedded white space). 1293See also 1294.Ql Cm \&:[*] . 1295.It Cm \&:tw 1296Causes the value to be treated as a sequence of 1297words delimited by white space. 1298See also 1299.Ql Cm \&:[@] . 1300.Sm off 1301.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW 1302.Sm on 1303Modify the first occurrence of 1304.Ar old_string 1305in the variable's value, replacing it with 1306.Ar new_string . 1307If a 1308.Ql g 1309is appended to the last slash of the pattern, all occurrences 1310in each word are replaced. 1311If a 1312.Ql 1 1313is appended to the last slash of the pattern, only the first word 1314is affected. 1315If a 1316.Ql W 1317is appended to the last slash of the pattern, 1318then the value is treated as a single word 1319(possibly containing embedded white space). 1320If 1321.Ar old_string 1322begins with a caret 1323.Pq Ql ^ , 1324.Ar old_string 1325is anchored at the beginning of each word. 1326If 1327.Ar old_string 1328ends with a dollar sign 1329.Pq Ql \&$ , 1330it is anchored at the end of each word. 1331Inside 1332.Ar new_string , 1333an ampersand 1334.Pq Ql & 1335is replaced by 1336.Ar old_string 1337(without any 1338.Ql ^ 1339or 1340.Ql \&$ ) . 1341Any character may be used as a delimiter for the parts of the modifier 1342string. 1343The anchoring, ampersand and delimiter characters may be escaped with a 1344backslash 1345.Pq Ql \e . 1346.Pp 1347Variable expansion occurs in the normal fashion inside both 1348.Ar old_string 1349and 1350.Ar new_string 1351with the single exception that a backslash is used to prevent the expansion 1352of a dollar sign 1353.Pq Ql \&$ , 1354not a preceding dollar sign as is usual. 1355.Sm off 1356.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW 1357.Sm on 1358The 1359.Cm \&:C 1360modifier is just like the 1361.Cm \&:S 1362modifier except that the old and new strings, instead of being 1363simple strings, are an extended regular expression (see 1364.Xr regex 3 ) 1365string 1366.Ar pattern 1367and an 1368.Xr ed 1 Ns \-style 1369string 1370.Ar replacement . 1371Normally, the first occurrence of the pattern 1372.Ar pattern 1373in each word of the value is substituted with 1374.Ar replacement . 1375The 1376.Ql 1 1377modifier causes the substitution to apply to at most one word; the 1378.Ql g 1379modifier causes the substitution to apply to as many instances of the 1380search pattern 1381.Ar pattern 1382as occur in the word or words it is found in; the 1383.Ql W 1384modifier causes the value to be treated as a single word 1385(possibly containing embedded white space). 1386Note that 1387.Ql 1 1388and 1389.Ql g 1390are orthogonal; the former specifies whether multiple words are 1391potentially affected, the latter whether multiple substitutions can 1392potentially occur within each affected word. 1393.Pp 1394As for the 1395.Cm \&:S 1396modifier, the 1397.Ar pattern 1398and 1399.Ar replacement 1400are subjected to variable expansion before being parsed as 1401regular expressions. 1402.It Cm \&:T 1403Replaces each word in the variable with its last component. 1404.It Cm \&:u 1405Remove adjacent duplicate words (like 1406.Xr uniq 1 ) . 1407.Sm off 1408.It Cm \&:\&? Ar true_string Cm \&: Ar false_string 1409.Sm on 1410If the variable name (not its value), when parsed as a .if conditional 1411expression, evaluates to true, return as its value the 1412.Ar true_string , 1413otherwise return the 1414.Ar false_string . 1415Since the variable name is used as the expression, \&:\&? must be the 1416first modifier after the variable name itself - which will, of course, 1417usually contain variable expansions. 1418A common error is trying to use expressions like 1419.Dl ${NUMBERS:M42:?match:no} 1420which actually tests defined(NUMBERS), 1421to determine is any words match "42" you need to use something like: 1422.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} . 1423.It Ar :old_string=new_string 1424This is the 1425.At V 1426style variable substitution. 1427It must be the last modifier specified. 1428If 1429.Ar old_string 1430or 1431.Ar new_string 1432do not contain the pattern matching character 1433.Ar % 1434then it is assumed that they are 1435anchored at the end of each word, so only suffixes or entire 1436words may be replaced. 1437Otherwise 1438.Ar % 1439is the substring of 1440.Ar old_string 1441to be replaced in 1442.Ar new_string . 1443If only 1444.Ar old_string 1445contains the pattern matching character 1446.Ar % , 1447and 1448.Ar old_string 1449matches, then the result is the 1450.Ar new_string . 1451If only the 1452.Ar new_string 1453contains the pattern matching character 1454.Ar % , 1455then it is not treated specially and it is printed as a literal 1456.Ar % 1457on match. 1458If there is more than one pattern matching character 1459.Ar ( % ) 1460in either the 1461.Ar new_string 1462or 1463.Ar old_string , 1464only the first instance is treated specially (as the pattern character); 1465all subsequent instances are treated as regular characters 1466.Pp 1467Variable expansion occurs in the normal fashion inside both 1468.Ar old_string 1469and 1470.Ar new_string 1471with the single exception that a backslash is used to prevent the 1472expansion of a dollar sign 1473.Pq Ql \&$ , 1474not a preceding dollar sign as is usual. 1475.Sm off 1476.It Cm \&:@ Ar temp Cm @ Ar string Cm @ 1477.Sm on 1478This is the loop expansion mechanism from the OSF Development 1479Environment (ODE) make. 1480Unlike 1481.Cm \&.for 1482loops expansion occurs at the time of 1483reference. 1484Assign 1485.Ar temp 1486to each word in the variable and evaluate 1487.Ar string . 1488The ODE convention is that 1489.Ar temp 1490should start and end with a period. 1491For example. 1492.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@} 1493.Pp 1494However a single character variable is often more readable: 1495.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@} 1496.It Cm \&:_[=var] 1497Save the current variable value in 1498.Ql $_ 1499or the named 1500.Va var 1501for later reference. 1502Example usage: 1503.Bd -literal -offset indent 1504M_cmpv.units = 1 1000 1000000 1505M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\ 1506\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh 1507 1508.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}} 1509 1510.Ed 1511Here 1512.Ql $_ 1513is used to save the result of the 1514.Ql :S 1515modifier which is later referenced using the index values from 1516.Ql :range . 1517.It Cm \&:U Ns Ar newval 1518If the variable is undefined 1519.Ar newval 1520is the value. 1521If the variable is defined, the existing value is returned. 1522This is another ODE make feature. 1523It is handy for setting per-target CFLAGS for instance: 1524.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}} 1525If a value is only required if the variable is undefined, use: 1526.Dl ${VAR:D:Unewval} 1527.It Cm \&:D Ns Ar newval 1528If the variable is defined 1529.Ar newval 1530is the value. 1531.It Cm \&:L 1532The name of the variable is the value. 1533.It Cm \&:P 1534The path of the node which has the same name as the variable 1535is the value. 1536If no such node exists or its path is null, then the 1537name of the variable is used. 1538In order for this modifier to work, the name (node) must at least have 1539appeared on the rhs of a dependency. 1540.Sm off 1541.It Cm \&:\&! Ar cmd Cm \&! 1542.Sm on 1543The output of running 1544.Ar cmd 1545is the value. 1546.It Cm \&:sh 1547If the variable is non-empty it is run as a command and the output 1548becomes the new value. 1549.It Cm \&::= Ns Ar str 1550The variable is assigned the value 1551.Ar str 1552after substitution. 1553This modifier and its variations are useful in 1554obscure situations such as wanting to set a variable when shell commands 1555are being parsed. 1556These assignment modifiers always expand to 1557nothing, so if appearing in a rule line by themselves should be 1558preceded with something to keep 1559.Nm 1560happy. 1561.Pp 1562The 1563.Ql Cm \&:: 1564helps avoid false matches with the 1565.At V 1566style 1567.Cm \&:= 1568modifier and since substitution always occurs the 1569.Cm \&::= 1570form is vaguely appropriate. 1571.It Cm \&::?= Ns Ar str 1572As for 1573.Cm \&::= 1574but only if the variable does not already have a value. 1575.It Cm \&::+= Ns Ar str 1576Append 1577.Ar str 1578to the variable. 1579.It Cm \&::!= Ns Ar cmd 1580Assign the output of 1581.Ar cmd 1582to the variable. 1583.It Cm \&:\&[ Ns Ar range Ns Cm \&] 1584Selects one or more words from the value, 1585or performs other operations related to the way in which the 1586value is divided into words. 1587.Pp 1588Ordinarily, a value is treated as a sequence of words 1589delimited by white space. 1590Some modifiers suppress this behavior, 1591causing a value to be treated as a single word 1592(possibly containing embedded white space). 1593An empty value, or a value that consists entirely of white-space, 1594is treated as a single word. 1595For the purposes of the 1596.Ql Cm \&:[] 1597modifier, the words are indexed both forwards using positive integers 1598(where index 1 represents the first word), 1599and backwards using negative integers 1600(where index \-1 represents the last word). 1601.Pp 1602The 1603.Ar range 1604is subjected to variable expansion, and the expanded result is 1605then interpreted as follows: 1606.Bl -tag -width index 1607.\" :[n] 1608.It Ar index 1609Selects a single word from the value. 1610.\" :[start..end] 1611.It Ar start Ns Cm \&.. Ns Ar end 1612Selects all words from 1613.Ar start 1614to 1615.Ar end , 1616inclusive. 1617For example, 1618.Ql Cm \&:[2..-1] 1619selects all words from the second word to the last word. 1620If 1621.Ar start 1622is greater than 1623.Ar end , 1624then the words are output in reverse order. 1625For example, 1626.Ql Cm \&:[-1..1] 1627selects all the words from last to first. 1628.\" :[*] 1629.It Cm \&* 1630Causes subsequent modifiers to treat the value as a single word 1631(possibly containing embedded white space). 1632Analogous to the effect of 1633\&"$*\&" 1634in Bourne shell. 1635.\" :[0] 1636.It 0 1637Means the same as 1638.Ql Cm \&:[*] . 1639.\" :[*] 1640.It Cm \&@ 1641Causes subsequent modifiers to treat the value as a sequence of words 1642delimited by white space. 1643Analogous to the effect of 1644\&"$@\&" 1645in Bourne shell. 1646.\" :[#] 1647.It Cm \&# 1648Returns the number of words in the value. 1649.El \" :[range] 1650.El 1651.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS 1652Makefile inclusion, conditional structures and for loops reminiscent 1653of the C programming language are provided in 1654.Nm . 1655All such structures are identified by a line beginning with a single 1656dot 1657.Pq Ql \&. 1658character. 1659Files are included with either 1660.Cm \&.include \&< Ns Ar file Ns Cm \&> 1661or 1662.Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q . 1663Variables between the angle brackets or double quotes are expanded 1664to form the file name. 1665If angle brackets are used, the included makefile is expected to be in 1666the system makefile directory. 1667If double quotes are used, the including makefile's directory and any 1668directories specified using the 1669.Fl I 1670option are searched before the system 1671makefile directory. 1672For compatibility with other versions of 1673.Nm 1674.Ql include file ... 1675is also accepted. 1676.Pp 1677If the include statement is written as 1678.Cm .-include 1679or as 1680.Cm .sinclude 1681then errors locating and/or opening include files are ignored. 1682.Pp 1683If the include statement is written as 1684.Cm .dinclude 1685not only are errors locating and/or opening include files ignored, 1686but stale dependencies within the included file will be ignored 1687just like 1688.Va .MAKE.DEPENDFILE . 1689.Pp 1690Conditional expressions are also preceded by a single dot as the first 1691character of a line. 1692The possible conditionals are as follows: 1693.Bl -tag -width Ds 1694.It Ic .error Ar message 1695The message is printed along with the name of the makefile and line number, 1696then 1697.Nm 1698will exit. 1699.It Ic .export Ar variable ... 1700Export the specified global variable. 1701If no variable list is provided, all globals are exported 1702except for internal variables (those that start with 1703.Ql \&. ) . 1704This is not affected by the 1705.Fl X 1706flag, so should be used with caution. 1707For compatibility with other 1708.Nm 1709programs 1710.Ql export variable=value 1711is also accepted. 1712.Pp 1713Appending a variable name to 1714.Va .MAKE.EXPORTED 1715is equivalent to exporting a variable. 1716.It Ic .export-env Ar variable ... 1717The same as 1718.Ql .export , 1719except that the variable is not appended to 1720.Va .MAKE.EXPORTED . 1721This allows exporting a value to the environment which is different from that 1722used by 1723.Nm 1724internally. 1725.It Ic .export-literal Ar variable ... 1726The same as 1727.Ql .export-env , 1728except that variables in the value are not expanded. 1729.It Ic .info Ar message 1730The message is printed along with the name of the makefile and line number. 1731.It Ic .undef Ar variable 1732Un-define the specified global variable. 1733Only global variables may be un-defined. 1734.It Ic .unexport Ar variable ... 1735The opposite of 1736.Ql .export . 1737The specified global 1738.Va variable 1739will be removed from 1740.Va .MAKE.EXPORTED . 1741If no variable list is provided, all globals are unexported, 1742and 1743.Va .MAKE.EXPORTED 1744deleted. 1745.It Ic .unexport-env 1746Unexport all globals previously exported and 1747clear the environment inherited from the parent. 1748This operation will cause a memory leak of the original environment, 1749so should be used sparingly. 1750Testing for 1751.Va .MAKE.LEVEL 1752being 0, would make sense. 1753Also note that any variables which originated in the parent environment 1754should be explicitly preserved if desired. 1755For example: 1756.Bd -literal -offset indent 1757.Li .if ${.MAKE.LEVEL} == 0 1758PATH := ${PATH} 1759.Li .unexport-env 1760.Li .export PATH 1761.Li .endif 1762.Pp 1763.Ed 1764Would result in an environment containing only 1765.Ql Ev PATH , 1766which is the minimal useful environment. 1767Actually 1768.Ql Ev .MAKE.LEVEL 1769will also be pushed into the new environment. 1770.It Ic .warning Ar message 1771The message prefixed by 1772.Ql Pa warning: 1773is printed along with the name of the makefile and line number. 1774.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ... 1775Test the value of an expression. 1776.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1777Test the value of a variable. 1778.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1779Test the value of a variable. 1780.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1781Test the target being built. 1782.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ... 1783Test the target being built. 1784.It Ic .else 1785Reverse the sense of the last conditional. 1786.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ... 1787A combination of 1788.Ql Ic .else 1789followed by 1790.Ql Ic .if . 1791.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1792A combination of 1793.Ql Ic .else 1794followed by 1795.Ql Ic .ifdef . 1796.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1797A combination of 1798.Ql Ic .else 1799followed by 1800.Ql Ic .ifndef . 1801.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1802A combination of 1803.Ql Ic .else 1804followed by 1805.Ql Ic .ifmake . 1806.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1807A combination of 1808.Ql Ic .else 1809followed by 1810.Ql Ic .ifnmake . 1811.It Ic .endif 1812End the body of the conditional. 1813.El 1814.Pp 1815The 1816.Ar operator 1817may be any one of the following: 1818.Bl -tag -width "Cm XX" 1819.It Cm \&|\&| 1820Logical OR. 1821.It Cm \&&& 1822Logical 1823.Tn AND ; 1824of higher precedence than 1825.Dq \&|\&| . 1826.El 1827.Pp 1828As in C, 1829.Nm 1830will only evaluate a conditional as far as is necessary to determine 1831its value. 1832Parentheses may be used to change the order of evaluation. 1833The boolean operator 1834.Ql Ic \&! 1835may be used to logically negate an entire 1836conditional. 1837It is of higher precedence than 1838.Ql Ic \&&& . 1839.Pp 1840The value of 1841.Ar expression 1842may be any of the following: 1843.Bl -tag -width defined 1844.It Ic defined 1845Takes a variable name as an argument and evaluates to true if the variable 1846has been defined. 1847.It Ic make 1848Takes a target name as an argument and evaluates to true if the target 1849was specified as part of 1850.Nm Ns 's 1851command line or was declared the default target (either implicitly or 1852explicitly, see 1853.Va .MAIN ) 1854before the line containing the conditional. 1855.It Ic empty 1856Takes a variable, with possible modifiers, and evaluates to true if 1857the expansion of the variable would result in an empty string. 1858.It Ic exists 1859Takes a file name as an argument and evaluates to true if the file exists. 1860The file is searched for on the system search path (see 1861.Va .PATH ) . 1862.It Ic target 1863Takes a target name as an argument and evaluates to true if the target 1864has been defined. 1865.It Ic commands 1866Takes a target name as an argument and evaluates to true if the target 1867has been defined and has commands associated with it. 1868.El 1869.Pp 1870.Ar Expression 1871may also be an arithmetic or string comparison. 1872Variable expansion is 1873performed on both sides of the comparison, after which the integral 1874values are compared. 1875A value is interpreted as hexadecimal if it is 1876preceded by 0x, otherwise it is decimal; octal numbers are not supported. 1877The standard C relational operators are all supported. 1878If after 1879variable expansion, either the left or right hand side of a 1880.Ql Ic == 1881or 1882.Ql Ic "!=" 1883operator is not an integral value, then 1884string comparison is performed between the expanded 1885variables. 1886If no relational operator is given, it is assumed that the expanded 1887variable is being compared against 0 or an empty string in the case 1888of a string comparison. 1889.Pp 1890When 1891.Nm 1892is evaluating one of these conditional expressions, and it encounters 1893a (white-space separated) word it doesn't recognize, either the 1894.Dq make 1895or 1896.Dq defined 1897expression is applied to it, depending on the form of the conditional. 1898If the form is 1899.Ql Ic .ifdef , 1900.Ql Ic .ifndef , 1901or 1902.Ql Ic .if 1903the 1904.Dq defined 1905expression is applied. 1906Similarly, if the form is 1907.Ql Ic .ifmake 1908or 1909.Ql Ic .ifnmake , 1910the 1911.Dq make 1912expression is applied. 1913.Pp 1914If the conditional evaluates to true the parsing of the makefile continues 1915as before. 1916If it evaluates to false, the following lines are skipped. 1917In both cases this continues until a 1918.Ql Ic .else 1919or 1920.Ql Ic .endif 1921is found. 1922.Pp 1923For loops are typically used to apply a set of rules to a list of files. 1924The syntax of a for loop is: 1925.Pp 1926.Bl -tag -compact -width Ds 1927.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression 1928.It Aq make-rules 1929.It Ic \&.endfor 1930.El 1931.Pp 1932After the for 1933.Ic expression 1934is evaluated, it is split into words. 1935On each iteration of the loop, one word is taken and assigned to each 1936.Ic variable , 1937in order, and these 1938.Ic variables 1939are substituted into the 1940.Ic make-rules 1941inside the body of the for loop. 1942The number of words must come out even; that is, if there are three 1943iteration variables, the number of words provided must be a multiple 1944of three. 1945.Sh COMMENTS 1946Comments begin with a hash 1947.Pq Ql \&# 1948character, anywhere but in a shell 1949command line, and continue to the end of an unescaped new line. 1950.Sh SPECIAL SOURCES (ATTRIBUTES) 1951.Bl -tag -width .IGNOREx 1952.It Ic .EXEC 1953Target is never out of date, but always execute commands anyway. 1954.It Ic .IGNORE 1955Ignore any errors from the commands associated with this target, exactly 1956as if they all were preceded by a dash 1957.Pq Ql \- . 1958.\" .It Ic .INVISIBLE 1959.\" XXX 1960.\" .It Ic .JOIN 1961.\" XXX 1962.It Ic .MADE 1963Mark all sources of this target as being up-to-date. 1964.It Ic .MAKE 1965Execute the commands associated with this target even if the 1966.Fl n 1967or 1968.Fl t 1969options were specified. 1970Normally used to mark recursive 1971.Nm Ns s . 1972.It Ic .META 1973Create a meta file for the target, even if it is flagged as 1974.Ic .PHONY , 1975.Ic .MAKE , 1976or 1977.Ic .SPECIAL . 1978Usage in conjunction with 1979.Ic .MAKE 1980is the most likely case. 1981In "meta" mode, the target is out-of-date if the meta file is missing. 1982.It Ic .NOMETA 1983Do not create a meta file for the target. 1984Meta files are also not created for 1985.Ic .PHONY , 1986.Ic .MAKE , 1987or 1988.Ic .SPECIAL 1989targets. 1990.It Ic .NOMETA_CMP 1991Ignore differences in commands when deciding if target is out of date. 1992This is useful if the command contains a value which always changes. 1993If the number of commands change, though, the target will still be out of date. 1994The same effect applies to any command line that uses the variable 1995.Va .OODATE , 1996which can be used for that purpose even when not otherwise needed or desired: 1997.Bd -literal -offset indent 1998 1999skip-compare-for-some: 2000 @echo this will be compared 2001 @echo this will not ${.OODATE:M.NOMETA_CMP} 2002 @echo this will also be compared 2003 2004.Ed 2005The 2006.Cm \&:M 2007pattern suppresses any expansion of the unwanted variable. 2008.It Ic .NOPATH 2009Do not search for the target in the directories specified by 2010.Ic .PATH . 2011.It Ic .NOTMAIN 2012Normally 2013.Nm 2014selects the first target it encounters as the default target to be built 2015if no target was specified. 2016This source prevents this target from being selected. 2017.It Ic .OPTIONAL 2018If a target is marked with this attribute and 2019.Nm 2020can't figure out how to create it, it will ignore this fact and assume 2021the file isn't needed or already exists. 2022.It Ic .PHONY 2023The target does not 2024correspond to an actual file; it is always considered to be out of date, 2025and will not be created with the 2026.Fl t 2027option. 2028Suffix-transformation rules are not applied to 2029.Ic .PHONY 2030targets. 2031.It Ic .PRECIOUS 2032When 2033.Nm 2034is interrupted, it normally removes any partially made targets. 2035This source prevents the target from being removed. 2036.It Ic .RECURSIVE 2037Synonym for 2038.Ic .MAKE . 2039.It Ic .SILENT 2040Do not echo any of the commands associated with this target, exactly 2041as if they all were preceded by an at sign 2042.Pq Ql @ . 2043.It Ic .USE 2044Turn the target into 2045.Nm Ns 's 2046version of a macro. 2047When the target is used as a source for another target, the other target 2048acquires the commands, sources, and attributes (except for 2049.Ic .USE ) 2050of the 2051source. 2052If the target already has commands, the 2053.Ic .USE 2054target's commands are appended 2055to them. 2056.It Ic .USEBEFORE 2057Exactly like 2058.Ic .USE , 2059but prepend the 2060.Ic .USEBEFORE 2061target commands to the target. 2062.It Ic .WAIT 2063If 2064.Ic .WAIT 2065appears in a dependency line, the sources that precede it are 2066made before the sources that succeed it in the line. 2067Since the dependents of files are not made until the file itself 2068could be made, this also stops the dependents being built unless they 2069are needed for another branch of the dependency tree. 2070So given: 2071.Bd -literal 2072x: a .WAIT b 2073 echo x 2074a: 2075 echo a 2076b: b1 2077 echo b 2078b1: 2079 echo b1 2080 2081.Ed 2082the output is always 2083.Ql a , 2084.Ql b1 , 2085.Ql b , 2086.Ql x . 2087.br 2088The ordering imposed by 2089.Ic .WAIT 2090is only relevant for parallel makes. 2091.El 2092.Sh SPECIAL TARGETS 2093Special targets may not be included with other targets, i.e. they must be 2094the only target specified. 2095.Bl -tag -width .BEGINx 2096.It Ic .BEGIN 2097Any command lines attached to this target are executed before anything 2098else is done. 2099.It Ic .DEFAULT 2100This is sort of a 2101.Ic .USE 2102rule for any target (that was used only as a 2103source) that 2104.Nm 2105can't figure out any other way to create. 2106Only the shell script is used. 2107The 2108.Ic .IMPSRC 2109variable of a target that inherits 2110.Ic .DEFAULT Ns 's 2111commands is set 2112to the target's own name. 2113.It Ic .DELETE_ON_ERROR 2114If this target is present in the makefile, it globally causes make to 2115delete targets whose commands fail. 2116(By default, only targets whose commands are interrupted during 2117execution are deleted. 2118This is the historical behavior.) 2119This setting can be used to help prevent half-finished or malformed 2120targets from being left around and corrupting future rebuilds. 2121.It Ic .END 2122Any command lines attached to this target are executed after everything 2123else is done. 2124.It Ic .ERROR 2125Any command lines attached to this target are executed when another target fails. 2126The 2127.Ic .ERROR_TARGET 2128variable is set to the target that failed. 2129See also 2130.Ic MAKE_PRINT_VAR_ON_ERROR . 2131.It Ic .IGNORE 2132Mark each of the sources with the 2133.Ic .IGNORE 2134attribute. 2135If no sources are specified, this is the equivalent of specifying the 2136.Fl i 2137option. 2138.It Ic .INTERRUPT 2139If 2140.Nm 2141is interrupted, the commands for this target will be executed. 2142.It Ic .MAIN 2143If no target is specified when 2144.Nm 2145is invoked, this target will be built. 2146.It Ic .MAKEFLAGS 2147This target provides a way to specify flags for 2148.Nm 2149when the makefile is used. 2150The flags are as if typed to the shell, though the 2151.Fl f 2152option will have 2153no effect. 2154.\" XXX: NOT YET!!!! 2155.\" .It Ic .NOTPARALLEL 2156.\" The named targets are executed in non parallel mode. 2157.\" If no targets are 2158.\" specified, then all targets are executed in non parallel mode. 2159.It Ic .NOPATH 2160Apply the 2161.Ic .NOPATH 2162attribute to any specified sources. 2163.It Ic .NOTPARALLEL 2164Disable parallel mode. 2165.It Ic .NO_PARALLEL 2166Synonym for 2167.Ic .NOTPARALLEL , 2168for compatibility with other pmake variants. 2169.It Ic .OBJDIR 2170The source is a new value for 2171.Ql Va .OBJDIR . 2172If it exists, 2173.Nm 2174will 2175.Xr chdir 2 2176to it and update the value of 2177.Ql Va .OBJDIR . 2178.It Ic .ORDER 2179The named targets are made in sequence. 2180This ordering does not add targets to the list of targets to be made. 2181Since the dependents of a target do not get built until the target itself 2182could be built, unless 2183.Ql a 2184is built by another part of the dependency graph, 2185the following is a dependency loop: 2186.Bd -literal 2187\&.ORDER: b a 2188b: a 2189.Ed 2190.Pp 2191The ordering imposed by 2192.Ic .ORDER 2193is only relevant for parallel makes. 2194.\" XXX: NOT YET!!!! 2195.\" .It Ic .PARALLEL 2196.\" The named targets are executed in parallel mode. 2197.\" If no targets are 2198.\" specified, then all targets are executed in parallel mode. 2199.It Ic .PATH 2200The sources are directories which are to be searched for files not 2201found in the current directory. 2202If no sources are specified, any previously specified directories are 2203deleted. 2204If the source is the special 2205.Ic .DOTLAST 2206target, then the current working 2207directory is searched last. 2208.It Ic .PATH. Ns Va suffix 2209Like 2210.Ic .PATH 2211but applies only to files with a particular suffix. 2212The suffix must have been previously declared with 2213.Ic .SUFFIXES . 2214.It Ic .PHONY 2215Apply the 2216.Ic .PHONY 2217attribute to any specified sources. 2218.It Ic .PRECIOUS 2219Apply the 2220.Ic .PRECIOUS 2221attribute to any specified sources. 2222If no sources are specified, the 2223.Ic .PRECIOUS 2224attribute is applied to every 2225target in the file. 2226.It Ic .SHELL 2227Sets the shell that 2228.Nm 2229will use to execute commands. 2230The sources are a set of 2231.Ar field=value 2232pairs. 2233.Bl -tag -width hasErrCtls 2234.It Ar name 2235This is the minimal specification, used to select one of the built-in 2236shell specs; 2237.Ar sh , 2238.Ar ksh , 2239and 2240.Ar csh . 2241.It Ar path 2242Specifies the path to the shell. 2243.It Ar hasErrCtl 2244Indicates whether the shell supports exit on error. 2245.It Ar check 2246The command to turn on error checking. 2247.It Ar ignore 2248The command to disable error checking. 2249.It Ar echo 2250The command to turn on echoing of commands executed. 2251.It Ar quiet 2252The command to turn off echoing of commands executed. 2253.It Ar filter 2254The output to filter after issuing the 2255.Ar quiet 2256command. 2257It is typically identical to 2258.Ar quiet . 2259.It Ar errFlag 2260The flag to pass the shell to enable error checking. 2261.It Ar echoFlag 2262The flag to pass the shell to enable command echoing. 2263.It Ar newline 2264The string literal to pass the shell that results in a single newline 2265character when used outside of any quoting characters. 2266.El 2267Example: 2268.Bd -literal 2269\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e 2270 check="set \-e" ignore="set +e" \e 2271 echo="set \-v" quiet="set +v" filter="set +v" \e 2272 echoFlag=v errFlag=e newline="'\en'" 2273.Ed 2274.It Ic .SILENT 2275Apply the 2276.Ic .SILENT 2277attribute to any specified sources. 2278If no sources are specified, the 2279.Ic .SILENT 2280attribute is applied to every 2281command in the file. 2282.It Ic .STALE 2283This target gets run when a dependency file contains stale entries, having 2284.Va .ALLSRC 2285set to the name of that dependency file. 2286.It Ic .SUFFIXES 2287Each source specifies a suffix to 2288.Nm . 2289If no sources are specified, any previously specified suffixes are deleted. 2290It allows the creation of suffix-transformation rules. 2291.Pp 2292Example: 2293.Bd -literal 2294\&.SUFFIXES: .o 2295\&.c.o: 2296 cc \-o ${.TARGET} \-c ${.IMPSRC} 2297.Ed 2298.El 2299.Sh ENVIRONMENT 2300.Nm 2301uses the following environment variables, if they exist: 2302.Ev MACHINE , 2303.Ev MACHINE_ARCH , 2304.Ev MAKE , 2305.Ev MAKEFLAGS , 2306.Ev MAKEOBJDIR , 2307.Ev MAKEOBJDIRPREFIX , 2308.Ev MAKESYSPATH , 2309.Ev PWD , 2310and 2311.Ev TMPDIR . 2312.Pp 2313.Ev MAKEOBJDIRPREFIX 2314and 2315.Ev MAKEOBJDIR 2316may only be set in the environment or on the command line to 2317.Nm 2318and not as makefile variables; 2319see the description of 2320.Ql Va .OBJDIR 2321for more details. 2322.Sh FILES 2323.Bl -tag -width /usr/share/mk -compact 2324.It .depend 2325list of dependencies 2326.It Makefile 2327list of dependencies 2328.It makefile 2329list of dependencies 2330.It sys.mk 2331system makefile 2332.It /usr/share/mk 2333system makefile directory 2334.El 2335.Sh COMPATIBILITY 2336The basic make syntax is compatible between different versions of make; 2337however the special variables, variable modifiers and conditionals are not. 2338.Ss Older versions 2339An incomplete list of changes in older versions of 2340.Nm : 2341.Pp 2342The way that .for loop variables are substituted changed after 2343.Nx 5.0 2344so that they still appear to be variable expansions. 2345In particular this stops them being treated as syntax, and removes some 2346obscure problems using them in .if statements. 2347.Pp 2348The way that parallel makes are scheduled changed in 2349.Nx 4.0 2350so that .ORDER and .WAIT apply recursively to the dependent nodes. 2351The algorithms used may change again in the future. 2352.Ss Other make dialects 2353Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not 2354support most of the features of 2355.Nm 2356as described in this manual. 2357Most notably: 2358.Bl -bullet -offset indent 2359.It 2360The 2361.Ic .WAIT 2362and 2363.Ic .ORDER 2364declarations and most functionality pertaining to parallelization. 2365(GNU make supports parallelization but lacks these features needed to 2366control it effectively.) 2367.It 2368Directives, including for loops and conditionals and most of the 2369forms of include files. 2370(GNU make has its own incompatible and less powerful syntax for 2371conditionals.) 2372.It 2373All built-in variables that begin with a dot. 2374.It 2375Most of the special sources and targets that begin with a dot, 2376with the notable exception of 2377.Ic .PHONY , 2378.Ic .PRECIOUS , 2379and 2380.Ic .SUFFIXES . 2381.It 2382Variable modifiers, except for the 2383.Dl :old=new 2384string substitution, which does not portably support globbing with 2385.Ql % 2386and historically only works on declared suffixes. 2387.It 2388The 2389.Ic $> 2390variable even in its short form; most makes support this functionality 2391but its name varies. 2392.El 2393.Pp 2394Some features are somewhat more portable, such as assignment with 2395.Ic += , 2396.Ic ?= , 2397and 2398.Ic != . 2399The 2400.Ic .PATH 2401functionality is based on an older feature 2402.Ic VPATH 2403found in GNU make and many versions of SVR4 make; however, 2404historically its behavior is too ill-defined (and too buggy) to rely 2405upon. 2406.Pp 2407The 2408.Ic $@ 2409and 2410.Ic $< 2411variables are more or less universally portable, as is the 2412.Ic $(MAKE) 2413variable. 2414Basic use of suffix rules (for files only in the current directory, 2415not trying to chain transformations together, etc.) is also reasonably 2416portable. 2417.Sh SEE ALSO 2418.Xr mkdep 1 , 2419.Xr style.Makefile 5 2420.Sh HISTORY 2421A 2422.Nm 2423command appeared in 2424.At v7 . 2425This 2426.Nm 2427implementation is based on Adam De Boor's pmake program which was written 2428for Sprite at Berkeley. 2429It was designed to be a parallel distributed make running jobs on different 2430machines using a daemon called 2431.Dq customs . 2432.Pp 2433Historically the target/dependency 2434.Dq FRC 2435has been used to FoRCe rebuilding (since the target/dependency 2436does not exist... unless someone creates an 2437.Dq FRC 2438file). 2439.Sh BUGS 2440The 2441.Nm 2442syntax is difficult to parse without actually acting on the data. 2443For instance, finding the end of a variable's use should involve scanning 2444each of the modifiers, using the correct terminator for each field. 2445In many places 2446.Nm 2447just counts {} and () in order to find the end of a variable expansion. 2448.Pp 2449There is no way of escaping a space character in a filename. 2450