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.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. 1210.It Cm \&:Or 1211Order every word in variable in reverse alphabetical order. 1212.It Cm \&:Ox 1213Randomize words in variable. 1214The results will be different each time you are referring to the 1215modified variable; use the assignment with expansion 1216.Pq Ql Cm \&:= 1217to prevent such behavior. 1218For example, 1219.Bd -literal -offset indent 1220LIST= uno due tre quattro 1221RANDOM_LIST= ${LIST:Ox} 1222STATIC_RANDOM_LIST:= ${LIST:Ox} 1223 1224all: 1225 @echo "${RANDOM_LIST}" 1226 @echo "${RANDOM_LIST}" 1227 @echo "${STATIC_RANDOM_LIST}" 1228 @echo "${STATIC_RANDOM_LIST}" 1229.Ed 1230may produce output similar to: 1231.Bd -literal -offset indent 1232quattro due tre uno 1233tre due quattro uno 1234due uno quattro tre 1235due uno quattro tre 1236.Ed 1237.It Cm \&:Q 1238Quotes every shell meta-character in the variable, so that it can be passed 1239safely to the shell. 1240.It Cm \&:q 1241Quotes every shell meta-character in the variable, and also doubles 1242.Sq $ 1243characters so that it can be passed 1244safely through recursive invocations of 1245.Nm . 1246This is equivalent to: 1247.Sq \&:S/\e\&$/&&/g:Q . 1248.It Cm \&:R 1249Replaces each word in the variable with everything but its suffix. 1250.It Cm \&:range[=count] 1251The value is an integer sequence representing the words of the original 1252value, or the supplied 1253.Va count . 1254.It Cm \&:gmtime[=utc] 1255The value is a format string for 1256.Xr strftime 3 , 1257using 1258.Xr gmtime 3 . 1259If a 1260.Va utc 1261value is not provided or is 0, the current time is used. 1262.It Cm \&:hash 1263Compute a 32-bit hash of the value and encode it as hex digits. 1264.It Cm \&:localtime[=utc] 1265The value is a format string for 1266.Xr strftime 3 , 1267using 1268.Xr localtime 3 . 1269If a 1270.Va utc 1271value is not provided or is 0, the current time is used. 1272.It Cm \&:tA 1273Attempt to convert variable to an absolute path using 1274.Xr realpath 3 , 1275if that fails, the value is unchanged. 1276.It Cm \&:tl 1277Converts variable to lower-case letters. 1278.It Cm \&:ts Ns Ar c 1279Words in the variable are normally separated by a space on expansion. 1280This modifier sets the separator to the character 1281.Ar c . 1282If 1283.Ar c 1284is omitted, then no separator is used. 1285The common escapes (including octal numeric codes), work as expected. 1286.It Cm \&:tu 1287Converts variable to upper-case letters. 1288.It Cm \&:tW 1289Causes the value to be treated as a single word 1290(possibly containing embedded white space). 1291See also 1292.Ql Cm \&:[*] . 1293.It Cm \&:tw 1294Causes the value to be treated as a sequence of 1295words delimited by white space. 1296See also 1297.Ql Cm \&:[@] . 1298.Sm off 1299.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW 1300.Sm on 1301Modify the first occurrence of 1302.Ar old_string 1303in the variable's value, replacing it with 1304.Ar new_string . 1305If a 1306.Ql g 1307is appended to the last slash of the pattern, all occurrences 1308in each word are replaced. 1309If a 1310.Ql 1 1311is appended to the last slash of the pattern, only the first word 1312is affected. 1313If a 1314.Ql W 1315is appended to the last slash of the pattern, 1316then the value is treated as a single word 1317(possibly containing embedded white space). 1318If 1319.Ar old_string 1320begins with a caret 1321.Pq Ql ^ , 1322.Ar old_string 1323is anchored at the beginning of each word. 1324If 1325.Ar old_string 1326ends with a dollar sign 1327.Pq Ql \&$ , 1328it is anchored at the end of each word. 1329Inside 1330.Ar new_string , 1331an ampersand 1332.Pq Ql & 1333is replaced by 1334.Ar old_string 1335(without any 1336.Ql ^ 1337or 1338.Ql \&$ ) . 1339Any character may be used as a delimiter for the parts of the modifier 1340string. 1341The anchoring, ampersand and delimiter characters may be escaped with a 1342backslash 1343.Pq Ql \e . 1344.Pp 1345Variable expansion occurs in the normal fashion inside both 1346.Ar old_string 1347and 1348.Ar new_string 1349with the single exception that a backslash is used to prevent the expansion 1350of a dollar sign 1351.Pq Ql \&$ , 1352not a preceding dollar sign as is usual. 1353.Sm off 1354.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW 1355.Sm on 1356The 1357.Cm \&:C 1358modifier is just like the 1359.Cm \&:S 1360modifier except that the old and new strings, instead of being 1361simple strings, are an extended regular expression (see 1362.Xr regex 3 ) 1363string 1364.Ar pattern 1365and an 1366.Xr ed 1 Ns \-style 1367string 1368.Ar replacement . 1369Normally, the first occurrence of the pattern 1370.Ar pattern 1371in each word of the value is substituted with 1372.Ar replacement . 1373The 1374.Ql 1 1375modifier causes the substitution to apply to at most one word; the 1376.Ql g 1377modifier causes the substitution to apply to as many instances of the 1378search pattern 1379.Ar pattern 1380as occur in the word or words it is found in; the 1381.Ql W 1382modifier causes the value to be treated as a single word 1383(possibly containing embedded white space). 1384Note that 1385.Ql 1 1386and 1387.Ql g 1388are orthogonal; the former specifies whether multiple words are 1389potentially affected, the latter whether multiple substitutions can 1390potentially occur within each affected word. 1391.Pp 1392As for the 1393.Cm \&:S 1394modifier, the 1395.Ar pattern 1396and 1397.Ar replacement 1398are subjected to variable expansion before being parsed as 1399regular expressions. 1400.It Cm \&:T 1401Replaces each word in the variable with its last component. 1402.It Cm \&:u 1403Remove adjacent duplicate words (like 1404.Xr uniq 1 ) . 1405.Sm off 1406.It Cm \&:\&? Ar true_string Cm \&: Ar false_string 1407.Sm on 1408If the variable name (not its value), when parsed as a .if conditional 1409expression, evaluates to true, return as its value the 1410.Ar true_string , 1411otherwise return the 1412.Ar false_string . 1413Since the variable name is used as the expression, \&:\&? must be the 1414first modifier after the variable name itself - which will, of course, 1415usually contain variable expansions. 1416A common error is trying to use expressions like 1417.Dl ${NUMBERS:M42:?match:no} 1418which actually tests defined(NUMBERS), 1419to determine is any words match "42" you need to use something like: 1420.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} . 1421.It Ar :old_string=new_string 1422This is the 1423.At V 1424style variable substitution. 1425It must be the last modifier specified. 1426If 1427.Ar old_string 1428or 1429.Ar new_string 1430do not contain the pattern matching character 1431.Ar % 1432then it is assumed that they are 1433anchored at the end of each word, so only suffixes or entire 1434words may be replaced. 1435Otherwise 1436.Ar % 1437is the substring of 1438.Ar old_string 1439to be replaced in 1440.Ar new_string . 1441If only 1442.Ar old_string 1443contains the pattern matching character 1444.Ar % , 1445and 1446.Ar old_string 1447matches, then the result is the 1448.Ar new_string . 1449If only the 1450.Ar new_string 1451contains the pattern matching character 1452.Ar % , 1453then it is not treated specially and it is printed as a literal 1454.Ar % 1455on match. 1456If there is more than one pattern matching character 1457.Ar ( % ) 1458in either the 1459.Ar new_string 1460or 1461.Ar old_string , 1462only the first instance is treated specially (as the pattern character); 1463all subsequent instances are treated as regular characters 1464.Pp 1465Variable expansion occurs in the normal fashion inside both 1466.Ar old_string 1467and 1468.Ar new_string 1469with the single exception that a backslash is used to prevent the 1470expansion of a dollar sign 1471.Pq Ql \&$ , 1472not a preceding dollar sign as is usual. 1473.Sm off 1474.It Cm \&:@ Ar temp Cm @ Ar string Cm @ 1475.Sm on 1476This is the loop expansion mechanism from the OSF Development 1477Environment (ODE) make. 1478Unlike 1479.Cm \&.for 1480loops expansion occurs at the time of 1481reference. 1482Assign 1483.Ar temp 1484to each word in the variable and evaluate 1485.Ar string . 1486The ODE convention is that 1487.Ar temp 1488should start and end with a period. 1489For example. 1490.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@} 1491.Pp 1492However a single character variable is often more readable: 1493.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@} 1494.It Cm \&:_[=var] 1495Save the current variable value in 1496.Ql $_ 1497or the named 1498.Va var 1499for later reference. 1500Example usage: 1501.Bd -literal -offset indent 1502M_cmpv.units = 1 1000 1000000 1503M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\ 1504\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh 1505 1506.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}} 1507 1508.Ed 1509Here 1510.Ql $_ 1511is used to save the result of the 1512.Ql :S 1513modifier which is later referenced using the index values from 1514.Ql :range . 1515.It Cm \&:U Ns Ar newval 1516If the variable is undefined 1517.Ar newval 1518is the value. 1519If the variable is defined, the existing value is returned. 1520This is another ODE make feature. 1521It is handy for setting per-target CFLAGS for instance: 1522.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}} 1523If a value is only required if the variable is undefined, use: 1524.Dl ${VAR:D:Unewval} 1525.It Cm \&:D Ns Ar newval 1526If the variable is defined 1527.Ar newval 1528is the value. 1529.It Cm \&:L 1530The name of the variable is the value. 1531.It Cm \&:P 1532The path of the node which has the same name as the variable 1533is the value. 1534If no such node exists or its path is null, then the 1535name of the variable is used. 1536In order for this modifier to work, the name (node) must at least have 1537appeared on the rhs of a dependency. 1538.Sm off 1539.It Cm \&:\&! Ar cmd Cm \&! 1540.Sm on 1541The output of running 1542.Ar cmd 1543is the value. 1544.It Cm \&:sh 1545If the variable is non-empty it is run as a command and the output 1546becomes the new value. 1547.It Cm \&::= Ns Ar str 1548The variable is assigned the value 1549.Ar str 1550after substitution. 1551This modifier and its variations are useful in 1552obscure situations such as wanting to set a variable when shell commands 1553are being parsed. 1554These assignment modifiers always expand to 1555nothing, so if appearing in a rule line by themselves should be 1556preceded with something to keep 1557.Nm 1558happy. 1559.Pp 1560The 1561.Ql Cm \&:: 1562helps avoid false matches with the 1563.At V 1564style 1565.Cm \&:= 1566modifier and since substitution always occurs the 1567.Cm \&::= 1568form is vaguely appropriate. 1569.It Cm \&::?= Ns Ar str 1570As for 1571.Cm \&::= 1572but only if the variable does not already have a value. 1573.It Cm \&::+= Ns Ar str 1574Append 1575.Ar str 1576to the variable. 1577.It Cm \&::!= Ns Ar cmd 1578Assign the output of 1579.Ar cmd 1580to the variable. 1581.It Cm \&:\&[ Ns Ar range Ns Cm \&] 1582Selects one or more words from the value, 1583or performs other operations related to the way in which the 1584value is divided into words. 1585.Pp 1586Ordinarily, a value is treated as a sequence of words 1587delimited by white space. 1588Some modifiers suppress this behavior, 1589causing a value to be treated as a single word 1590(possibly containing embedded white space). 1591An empty value, or a value that consists entirely of white-space, 1592is treated as a single word. 1593For the purposes of the 1594.Ql Cm \&:[] 1595modifier, the words are indexed both forwards using positive integers 1596(where index 1 represents the first word), 1597and backwards using negative integers 1598(where index \-1 represents the last word). 1599.Pp 1600The 1601.Ar range 1602is subjected to variable expansion, and the expanded result is 1603then interpreted as follows: 1604.Bl -tag -width index 1605.\" :[n] 1606.It Ar index 1607Selects a single word from the value. 1608.\" :[start..end] 1609.It Ar start Ns Cm \&.. Ns Ar end 1610Selects all words from 1611.Ar start 1612to 1613.Ar end , 1614inclusive. 1615For example, 1616.Ql Cm \&:[2..-1] 1617selects all words from the second word to the last word. 1618If 1619.Ar start 1620is greater than 1621.Ar end , 1622then the words are output in reverse order. 1623For example, 1624.Ql Cm \&:[-1..1] 1625selects all the words from last to first. 1626If the list is already ordered, then this effectively reverses 1627the list, but it is more efficient to use 1628.Ql Cm \&:Or 1629instead of 1630.Ql Cm \&:O:[-1..1] . 1631.\" :[*] 1632.It Cm \&* 1633Causes subsequent modifiers to treat the value as a single word 1634(possibly containing embedded white space). 1635Analogous to the effect of 1636\&"$*\&" 1637in Bourne shell. 1638.\" :[0] 1639.It 0 1640Means the same as 1641.Ql Cm \&:[*] . 1642.\" :[*] 1643.It Cm \&@ 1644Causes subsequent modifiers to treat the value as a sequence of words 1645delimited by white space. 1646Analogous to the effect of 1647\&"$@\&" 1648in Bourne shell. 1649.\" :[#] 1650.It Cm \&# 1651Returns the number of words in the value. 1652.El \" :[range] 1653.El 1654.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS 1655Makefile inclusion, conditional structures and for loops reminiscent 1656of the C programming language are provided in 1657.Nm . 1658All such structures are identified by a line beginning with a single 1659dot 1660.Pq Ql \&. 1661character. 1662Files are included with either 1663.Cm \&.include \&< Ns Ar file Ns Cm \&> 1664or 1665.Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q . 1666Variables between the angle brackets or double quotes are expanded 1667to form the file name. 1668If angle brackets are used, the included makefile is expected to be in 1669the system makefile directory. 1670If double quotes are used, the including makefile's directory and any 1671directories specified using the 1672.Fl I 1673option are searched before the system 1674makefile directory. 1675For compatibility with other versions of 1676.Nm 1677.Ql include file ... 1678is also accepted. 1679.Pp 1680If the include statement is written as 1681.Cm .-include 1682or as 1683.Cm .sinclude 1684then errors locating and/or opening include files are ignored. 1685.Pp 1686If the include statement is written as 1687.Cm .dinclude 1688not only are errors locating and/or opening include files ignored, 1689but stale dependencies within the included file will be ignored 1690just like 1691.Va .MAKE.DEPENDFILE . 1692.Pp 1693Conditional expressions are also preceded by a single dot as the first 1694character of a line. 1695The possible conditionals are as follows: 1696.Bl -tag -width Ds 1697.It Ic .error Ar message 1698The message is printed along with the name of the makefile and line number, 1699then 1700.Nm 1701will exit. 1702.It Ic .export Ar variable ... 1703Export the specified global variable. 1704If no variable list is provided, all globals are exported 1705except for internal variables (those that start with 1706.Ql \&. ) . 1707This is not affected by the 1708.Fl X 1709flag, so should be used with caution. 1710For compatibility with other 1711.Nm 1712programs 1713.Ql export variable=value 1714is also accepted. 1715.Pp 1716Appending a variable name to 1717.Va .MAKE.EXPORTED 1718is equivalent to exporting a variable. 1719.It Ic .export-env Ar variable ... 1720The same as 1721.Ql .export , 1722except that the variable is not appended to 1723.Va .MAKE.EXPORTED . 1724This allows exporting a value to the environment which is different from that 1725used by 1726.Nm 1727internally. 1728.It Ic .export-literal Ar variable ... 1729The same as 1730.Ql .export-env , 1731except that variables in the value are not expanded. 1732.It Ic .info Ar message 1733The message is printed along with the name of the makefile and line number. 1734.It Ic .undef Ar variable 1735Un-define the specified global variable. 1736Only global variables may be un-defined. 1737.It Ic .unexport Ar variable ... 1738The opposite of 1739.Ql .export . 1740The specified global 1741.Va variable 1742will be removed from 1743.Va .MAKE.EXPORTED . 1744If no variable list is provided, all globals are unexported, 1745and 1746.Va .MAKE.EXPORTED 1747deleted. 1748.It Ic .unexport-env 1749Unexport all globals previously exported and 1750clear the environment inherited from the parent. 1751This operation will cause a memory leak of the original environment, 1752so should be used sparingly. 1753Testing for 1754.Va .MAKE.LEVEL 1755being 0, would make sense. 1756Also note that any variables which originated in the parent environment 1757should be explicitly preserved if desired. 1758For example: 1759.Bd -literal -offset indent 1760.Li .if ${.MAKE.LEVEL} == 0 1761PATH := ${PATH} 1762.Li .unexport-env 1763.Li .export PATH 1764.Li .endif 1765.Pp 1766.Ed 1767Would result in an environment containing only 1768.Ql Ev PATH , 1769which is the minimal useful environment. 1770Actually 1771.Ql Ev .MAKE.LEVEL 1772will also be pushed into the new environment. 1773.It Ic .warning Ar message 1774The message prefixed by 1775.Ql Pa warning: 1776is printed along with the name of the makefile and line number. 1777.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ... 1778Test the value of an expression. 1779.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1780Test the value of a variable. 1781.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1782Test the value of a variable. 1783.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1784Test the target being built. 1785.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ... 1786Test the target being built. 1787.It Ic .else 1788Reverse the sense of the last conditional. 1789.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ... 1790A combination of 1791.Ql Ic .else 1792followed by 1793.Ql Ic .if . 1794.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1795A combination of 1796.Ql Ic .else 1797followed by 1798.Ql Ic .ifdef . 1799.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1800A combination of 1801.Ql Ic .else 1802followed by 1803.Ql Ic .ifndef . 1804.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1805A combination of 1806.Ql Ic .else 1807followed by 1808.Ql Ic .ifmake . 1809.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1810A combination of 1811.Ql Ic .else 1812followed by 1813.Ql Ic .ifnmake . 1814.It Ic .endif 1815End the body of the conditional. 1816.El 1817.Pp 1818The 1819.Ar operator 1820may be any one of the following: 1821.Bl -tag -width "Cm XX" 1822.It Cm \&|\&| 1823Logical OR. 1824.It Cm \&&& 1825Logical 1826.Tn AND ; 1827of higher precedence than 1828.Dq \&|\&| . 1829.El 1830.Pp 1831As in C, 1832.Nm 1833will only evaluate a conditional as far as is necessary to determine 1834its value. 1835Parentheses may be used to change the order of evaluation. 1836The boolean operator 1837.Ql Ic \&! 1838may be used to logically negate an entire 1839conditional. 1840It is of higher precedence than 1841.Ql Ic \&&& . 1842.Pp 1843The value of 1844.Ar expression 1845may be any of the following: 1846.Bl -tag -width defined 1847.It Ic defined 1848Takes a variable name as an argument and evaluates to true if the variable 1849has been defined. 1850.It Ic make 1851Takes a target name as an argument and evaluates to true if the target 1852was specified as part of 1853.Nm Ns 's 1854command line or was declared the default target (either implicitly or 1855explicitly, see 1856.Va .MAIN ) 1857before the line containing the conditional. 1858.It Ic empty 1859Takes a variable, with possible modifiers, and evaluates to true if 1860the expansion of the variable would result in an empty string. 1861.It Ic exists 1862Takes a file name as an argument and evaluates to true if the file exists. 1863The file is searched for on the system search path (see 1864.Va .PATH ) . 1865.It Ic target 1866Takes a target name as an argument and evaluates to true if the target 1867has been defined. 1868.It Ic commands 1869Takes a target name as an argument and evaluates to true if the target 1870has been defined and has commands associated with it. 1871.El 1872.Pp 1873.Ar Expression 1874may also be an arithmetic or string comparison. 1875Variable expansion is 1876performed on both sides of the comparison, after which the integral 1877values are compared. 1878A value is interpreted as hexadecimal if it is 1879preceded by 0x, otherwise it is decimal; octal numbers are not supported. 1880The standard C relational operators are all supported. 1881If after 1882variable expansion, either the left or right hand side of a 1883.Ql Ic == 1884or 1885.Ql Ic "!=" 1886operator is not an integral value, then 1887string comparison is performed between the expanded 1888variables. 1889If no relational operator is given, it is assumed that the expanded 1890variable is being compared against 0 or an empty string in the case 1891of a string comparison. 1892.Pp 1893When 1894.Nm 1895is evaluating one of these conditional expressions, and it encounters 1896a (white-space separated) word it doesn't recognize, either the 1897.Dq make 1898or 1899.Dq defined 1900expression is applied to it, depending on the form of the conditional. 1901If the form is 1902.Ql Ic .ifdef , 1903.Ql Ic .ifndef , 1904or 1905.Ql Ic .if 1906the 1907.Dq defined 1908expression is applied. 1909Similarly, if the form is 1910.Ql Ic .ifmake 1911or 1912.Ql Ic .ifnmake , 1913the 1914.Dq make 1915expression is applied. 1916.Pp 1917If the conditional evaluates to true the parsing of the makefile continues 1918as before. 1919If it evaluates to false, the following lines are skipped. 1920In both cases this continues until a 1921.Ql Ic .else 1922or 1923.Ql Ic .endif 1924is found. 1925.Pp 1926For loops are typically used to apply a set of rules to a list of files. 1927The syntax of a for loop is: 1928.Pp 1929.Bl -tag -compact -width Ds 1930.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression 1931.It Aq make-rules 1932.It Ic \&.endfor 1933.El 1934.Pp 1935After the for 1936.Ic expression 1937is evaluated, it is split into words. 1938On each iteration of the loop, one word is taken and assigned to each 1939.Ic variable , 1940in order, and these 1941.Ic variables 1942are substituted into the 1943.Ic make-rules 1944inside the body of the for loop. 1945The number of words must come out even; that is, if there are three 1946iteration variables, the number of words provided must be a multiple 1947of three. 1948.Sh COMMENTS 1949Comments begin with a hash 1950.Pq Ql \&# 1951character, anywhere but in a shell 1952command line, and continue to the end of an unescaped new line. 1953.Sh SPECIAL SOURCES (ATTRIBUTES) 1954.Bl -tag -width .IGNOREx 1955.It Ic .EXEC 1956Target is never out of date, but always execute commands anyway. 1957.It Ic .IGNORE 1958Ignore any errors from the commands associated with this target, exactly 1959as if they all were preceded by a dash 1960.Pq Ql \- . 1961.\" .It Ic .INVISIBLE 1962.\" XXX 1963.\" .It Ic .JOIN 1964.\" XXX 1965.It Ic .MADE 1966Mark all sources of this target as being up-to-date. 1967.It Ic .MAKE 1968Execute the commands associated with this target even if the 1969.Fl n 1970or 1971.Fl t 1972options were specified. 1973Normally used to mark recursive 1974.Nm Ns s . 1975.It Ic .META 1976Create a meta file for the target, even if it is flagged as 1977.Ic .PHONY , 1978.Ic .MAKE , 1979or 1980.Ic .SPECIAL . 1981Usage in conjunction with 1982.Ic .MAKE 1983is the most likely case. 1984In "meta" mode, the target is out-of-date if the meta file is missing. 1985.It Ic .NOMETA 1986Do not create a meta file for the target. 1987Meta files are also not created for 1988.Ic .PHONY , 1989.Ic .MAKE , 1990or 1991.Ic .SPECIAL 1992targets. 1993.It Ic .NOMETA_CMP 1994Ignore differences in commands when deciding if target is out of date. 1995This is useful if the command contains a value which always changes. 1996If the number of commands change, though, the target will still be out of date. 1997The same effect applies to any command line that uses the variable 1998.Va .OODATE , 1999which can be used for that purpose even when not otherwise needed or desired: 2000.Bd -literal -offset indent 2001 2002skip-compare-for-some: 2003 @echo this will be compared 2004 @echo this will not ${.OODATE:M.NOMETA_CMP} 2005 @echo this will also be compared 2006 2007.Ed 2008The 2009.Cm \&:M 2010pattern suppresses any expansion of the unwanted variable. 2011.It Ic .NOPATH 2012Do not search for the target in the directories specified by 2013.Ic .PATH . 2014.It Ic .NOTMAIN 2015Normally 2016.Nm 2017selects the first target it encounters as the default target to be built 2018if no target was specified. 2019This source prevents this target from being selected. 2020.It Ic .OPTIONAL 2021If a target is marked with this attribute and 2022.Nm 2023can't figure out how to create it, it will ignore this fact and assume 2024the file isn't needed or already exists. 2025.It Ic .PHONY 2026The target does not 2027correspond to an actual file; it is always considered to be out of date, 2028and will not be created with the 2029.Fl t 2030option. 2031Suffix-transformation rules are not applied to 2032.Ic .PHONY 2033targets. 2034.It Ic .PRECIOUS 2035When 2036.Nm 2037is interrupted, it normally removes any partially made targets. 2038This source prevents the target from being removed. 2039.It Ic .RECURSIVE 2040Synonym for 2041.Ic .MAKE . 2042.It Ic .SILENT 2043Do not echo any of the commands associated with this target, exactly 2044as if they all were preceded by an at sign 2045.Pq Ql @ . 2046.It Ic .USE 2047Turn the target into 2048.Nm Ns 's 2049version of a macro. 2050When the target is used as a source for another target, the other target 2051acquires the commands, sources, and attributes (except for 2052.Ic .USE ) 2053of the 2054source. 2055If the target already has commands, the 2056.Ic .USE 2057target's commands are appended 2058to them. 2059.It Ic .USEBEFORE 2060Exactly like 2061.Ic .USE , 2062but prepend the 2063.Ic .USEBEFORE 2064target commands to the target. 2065.It Ic .WAIT 2066If 2067.Ic .WAIT 2068appears in a dependency line, the sources that precede it are 2069made before the sources that succeed it in the line. 2070Since the dependents of files are not made until the file itself 2071could be made, this also stops the dependents being built unless they 2072are needed for another branch of the dependency tree. 2073So given: 2074.Bd -literal 2075x: a .WAIT b 2076 echo x 2077a: 2078 echo a 2079b: b1 2080 echo b 2081b1: 2082 echo b1 2083 2084.Ed 2085the output is always 2086.Ql a , 2087.Ql b1 , 2088.Ql b , 2089.Ql x . 2090.br 2091The ordering imposed by 2092.Ic .WAIT 2093is only relevant for parallel makes. 2094.El 2095.Sh SPECIAL TARGETS 2096Special targets may not be included with other targets, i.e. they must be 2097the only target specified. 2098.Bl -tag -width .BEGINx 2099.It Ic .BEGIN 2100Any command lines attached to this target are executed before anything 2101else is done. 2102.It Ic .DEFAULT 2103This is sort of a 2104.Ic .USE 2105rule for any target (that was used only as a 2106source) that 2107.Nm 2108can't figure out any other way to create. 2109Only the shell script is used. 2110The 2111.Ic .IMPSRC 2112variable of a target that inherits 2113.Ic .DEFAULT Ns 's 2114commands is set 2115to the target's own name. 2116.It Ic .DELETE_ON_ERROR 2117If this target is present in the makefile, it globally causes make to 2118delete targets whose commands fail. 2119(By default, only targets whose commands are interrupted during 2120execution are deleted. 2121This is the historical behavior.) 2122This setting can be used to help prevent half-finished or malformed 2123targets from being left around and corrupting future rebuilds. 2124.It Ic .END 2125Any command lines attached to this target are executed after everything 2126else is done. 2127.It Ic .ERROR 2128Any command lines attached to this target are executed when another target fails. 2129The 2130.Ic .ERROR_TARGET 2131variable is set to the target that failed. 2132See also 2133.Ic MAKE_PRINT_VAR_ON_ERROR . 2134.It Ic .IGNORE 2135Mark each of the sources with the 2136.Ic .IGNORE 2137attribute. 2138If no sources are specified, this is the equivalent of specifying the 2139.Fl i 2140option. 2141.It Ic .INTERRUPT 2142If 2143.Nm 2144is interrupted, the commands for this target will be executed. 2145.It Ic .MAIN 2146If no target is specified when 2147.Nm 2148is invoked, this target will be built. 2149.It Ic .MAKEFLAGS 2150This target provides a way to specify flags for 2151.Nm 2152when the makefile is used. 2153The flags are as if typed to the shell, though the 2154.Fl f 2155option will have 2156no effect. 2157.\" XXX: NOT YET!!!! 2158.\" .It Ic .NOTPARALLEL 2159.\" The named targets are executed in non parallel mode. 2160.\" If no targets are 2161.\" specified, then all targets are executed in non parallel mode. 2162.It Ic .NOPATH 2163Apply the 2164.Ic .NOPATH 2165attribute to any specified sources. 2166.It Ic .NOTPARALLEL 2167Disable parallel mode. 2168.It Ic .NO_PARALLEL 2169Synonym for 2170.Ic .NOTPARALLEL , 2171for compatibility with other pmake variants. 2172.It Ic .OBJDIR 2173The source is a new value for 2174.Ql Va .OBJDIR . 2175If it exists, 2176.Nm 2177will 2178.Xr chdir 2 2179to it and update the value of 2180.Ql Va .OBJDIR . 2181.It Ic .ORDER 2182The named targets are made in sequence. 2183This ordering does not add targets to the list of targets to be made. 2184Since the dependents of a target do not get built until the target itself 2185could be built, unless 2186.Ql a 2187is built by another part of the dependency graph, 2188the following is a dependency loop: 2189.Bd -literal 2190\&.ORDER: b a 2191b: a 2192.Ed 2193.Pp 2194The ordering imposed by 2195.Ic .ORDER 2196is only relevant for parallel makes. 2197.\" XXX: NOT YET!!!! 2198.\" .It Ic .PARALLEL 2199.\" The named targets are executed in parallel mode. 2200.\" If no targets are 2201.\" specified, then all targets are executed in parallel mode. 2202.It Ic .PATH 2203The sources are directories which are to be searched for files not 2204found in the current directory. 2205If no sources are specified, any previously specified directories are 2206deleted. 2207If the source is the special 2208.Ic .DOTLAST 2209target, then the current working 2210directory is searched last. 2211.It Ic .PATH. Ns Va suffix 2212Like 2213.Ic .PATH 2214but applies only to files with a particular suffix. 2215The suffix must have been previously declared with 2216.Ic .SUFFIXES . 2217.It Ic .PHONY 2218Apply the 2219.Ic .PHONY 2220attribute to any specified sources. 2221.It Ic .PRECIOUS 2222Apply the 2223.Ic .PRECIOUS 2224attribute to any specified sources. 2225If no sources are specified, the 2226.Ic .PRECIOUS 2227attribute is applied to every 2228target in the file. 2229.It Ic .SHELL 2230Sets the shell that 2231.Nm 2232will use to execute commands. 2233The sources are a set of 2234.Ar field=value 2235pairs. 2236.Bl -tag -width hasErrCtls 2237.It Ar name 2238This is the minimal specification, used to select one of the built-in 2239shell specs; 2240.Ar sh , 2241.Ar ksh , 2242and 2243.Ar csh . 2244.It Ar path 2245Specifies the path to the shell. 2246.It Ar hasErrCtl 2247Indicates whether the shell supports exit on error. 2248.It Ar check 2249The command to turn on error checking. 2250.It Ar ignore 2251The command to disable error checking. 2252.It Ar echo 2253The command to turn on echoing of commands executed. 2254.It Ar quiet 2255The command to turn off echoing of commands executed. 2256.It Ar filter 2257The output to filter after issuing the 2258.Ar quiet 2259command. 2260It is typically identical to 2261.Ar quiet . 2262.It Ar errFlag 2263The flag to pass the shell to enable error checking. 2264.It Ar echoFlag 2265The flag to pass the shell to enable command echoing. 2266.It Ar newline 2267The string literal to pass the shell that results in a single newline 2268character when used outside of any quoting characters. 2269.El 2270Example: 2271.Bd -literal 2272\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e 2273 check="set \-e" ignore="set +e" \e 2274 echo="set \-v" quiet="set +v" filter="set +v" \e 2275 echoFlag=v errFlag=e newline="'\en'" 2276.Ed 2277.It Ic .SILENT 2278Apply the 2279.Ic .SILENT 2280attribute to any specified sources. 2281If no sources are specified, the 2282.Ic .SILENT 2283attribute is applied to every 2284command in the file. 2285.It Ic .STALE 2286This target gets run when a dependency file contains stale entries, having 2287.Va .ALLSRC 2288set to the name of that dependency file. 2289.It Ic .SUFFIXES 2290Each source specifies a suffix to 2291.Nm . 2292If no sources are specified, any previously specified suffixes are deleted. 2293It allows the creation of suffix-transformation rules. 2294.Pp 2295Example: 2296.Bd -literal 2297\&.SUFFIXES: .o 2298\&.c.o: 2299 cc \-o ${.TARGET} \-c ${.IMPSRC} 2300.Ed 2301.El 2302.Sh ENVIRONMENT 2303.Nm 2304uses the following environment variables, if they exist: 2305.Ev MACHINE , 2306.Ev MACHINE_ARCH , 2307.Ev MAKE , 2308.Ev MAKEFLAGS , 2309.Ev MAKEOBJDIR , 2310.Ev MAKEOBJDIRPREFIX , 2311.Ev MAKESYSPATH , 2312.Ev PWD , 2313and 2314.Ev TMPDIR . 2315.Pp 2316.Ev MAKEOBJDIRPREFIX 2317and 2318.Ev MAKEOBJDIR 2319may only be set in the environment or on the command line to 2320.Nm 2321and not as makefile variables; 2322see the description of 2323.Ql Va .OBJDIR 2324for more details. 2325.Sh FILES 2326.Bl -tag -width /usr/share/mk -compact 2327.It .depend 2328list of dependencies 2329.It Makefile 2330list of dependencies 2331.It makefile 2332list of dependencies 2333.It sys.mk 2334system makefile 2335.It /usr/share/mk 2336system makefile directory 2337.El 2338.Sh COMPATIBILITY 2339The basic make syntax is compatible between different versions of make; 2340however the special variables, variable modifiers and conditionals are not. 2341.Ss Older versions 2342An incomplete list of changes in older versions of 2343.Nm : 2344.Pp 2345The way that .for loop variables are substituted changed after 2346.Nx 5.0 2347so that they still appear to be variable expansions. 2348In particular this stops them being treated as syntax, and removes some 2349obscure problems using them in .if statements. 2350.Pp 2351The way that parallel makes are scheduled changed in 2352.Nx 4.0 2353so that .ORDER and .WAIT apply recursively to the dependent nodes. 2354The algorithms used may change again in the future. 2355.Ss Other make dialects 2356Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not 2357support most of the features of 2358.Nm 2359as described in this manual. 2360Most notably: 2361.Bl -bullet -offset indent 2362.It 2363The 2364.Ic .WAIT 2365and 2366.Ic .ORDER 2367declarations and most functionality pertaining to parallelization. 2368(GNU make supports parallelization but lacks these features needed to 2369control it effectively.) 2370.It 2371Directives, including for loops and conditionals and most of the 2372forms of include files. 2373(GNU make has its own incompatible and less powerful syntax for 2374conditionals.) 2375.It 2376All built-in variables that begin with a dot. 2377.It 2378Most of the special sources and targets that begin with a dot, 2379with the notable exception of 2380.Ic .PHONY , 2381.Ic .PRECIOUS , 2382and 2383.Ic .SUFFIXES . 2384.It 2385Variable modifiers, except for the 2386.Dl :old=new 2387string substitution, which does not portably support globbing with 2388.Ql % 2389and historically only works on declared suffixes. 2390.It 2391The 2392.Ic $> 2393variable even in its short form; most makes support this functionality 2394but its name varies. 2395.El 2396.Pp 2397Some features are somewhat more portable, such as assignment with 2398.Ic += , 2399.Ic ?= , 2400and 2401.Ic != . 2402The 2403.Ic .PATH 2404functionality is based on an older feature 2405.Ic VPATH 2406found in GNU make and many versions of SVR4 make; however, 2407historically its behavior is too ill-defined (and too buggy) to rely 2408upon. 2409.Pp 2410The 2411.Ic $@ 2412and 2413.Ic $< 2414variables are more or less universally portable, as is the 2415.Ic $(MAKE) 2416variable. 2417Basic use of suffix rules (for files only in the current directory, 2418not trying to chain transformations together, etc.) is also reasonably 2419portable. 2420.Sh SEE ALSO 2421.Xr mkdep 1 , 2422.Xr style.Makefile 5 2423.Sh HISTORY 2424A 2425.Nm 2426command appeared in 2427.At v7 . 2428This 2429.Nm 2430implementation is based on Adam De Boor's pmake program which was written 2431for Sprite at Berkeley. 2432It was designed to be a parallel distributed make running jobs on different 2433machines using a daemon called 2434.Dq customs . 2435.Pp 2436Historically the target/dependency 2437.Dq FRC 2438has been used to FoRCe rebuilding (since the target/dependency 2439does not exist... unless someone creates an 2440.Dq FRC 2441file). 2442.Sh BUGS 2443The 2444.Nm 2445syntax is difficult to parse without actually acting on the data. 2446For instance, finding the end of a variable's use should involve scanning 2447each of the modifiers, using the correct terminator for each field. 2448In many places 2449.Nm 2450just counts {} and () in order to find the end of a variable expansion. 2451.Pp 2452There is no way of escaping a space character in a filename. 2453