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 BMAKE 1 34.Os 35.Sh NAME 36.Nm bmake 37.Nd maintain program dependencies 38.Sh SYNOPSIS 39.Nm 40.Op Fl BeikNnqrstWwX 41.Op Fl C Ar directory 42.Op Fl D Ar variable 43.Op Fl d Ar flags 44.Op Fl f Ar makefile 45.Op Fl I Ar directory 46.Op Fl J Ar private 47.Op Fl j Ar max_jobs 48.Op Fl m Ar directory 49.Op Fl T Ar file 50.Op Fl V Ar variable 51.Op Fl v Ar variable 52.Op Ar variable=value 53.Op Ar target ... 54.Sh DESCRIPTION 55.Nm 56is a program designed to simplify the maintenance of other programs. 57Its input is a list of specifications as to the files upon which programs 58and other files depend. 59If no 60.Fl f Ar makefile 61makefile option is given, 62.Nm 63will try to open 64.Ql Pa makefile 65then 66.Ql Pa Makefile 67in order to find the specifications. 68If the file 69.Ql Pa .depend 70exists, it is read (see 71.Xr mkdep 1 ) . 72.Pp 73This manual page is intended as a reference document only. 74For a more thorough description of 75.Nm 76and makefiles, please refer to 77.%T "PMake \- A Tutorial" . 78.Pp 79.Nm 80will prepend the contents of the 81.Va MAKEFLAGS 82environment variable to the command line arguments before parsing them. 83.Pp 84The options are as follows: 85.Bl -tag -width Ds 86.It Fl B 87Try to be backwards compatible by executing a single shell per command and 88by executing the commands to make the sources of a dependency line in sequence. 89.It Fl C Ar directory 90Change to 91.Ar directory 92before reading the makefiles or doing anything else. 93If multiple 94.Fl C 95options are specified, each is interpreted relative to the previous one: 96.Fl C Pa / Fl C Pa etc 97is equivalent to 98.Fl C Pa /etc . 99.It Fl D Ar variable 100Define 101.Ar variable 102to be 1, in the global context. 103.It Fl d Ar [-]flags 104Turn on debugging, and specify which portions of 105.Nm 106are to print debugging information. 107Unless the flags are preceded by 108.Ql \- 109they are added to the 110.Va MAKEFLAGS 111environment variable and will be processed by any child make processes. 112By default, debugging information is printed to standard error, 113but this can be changed using the 114.Ar F 115debugging flag. 116The debugging output is always unbuffered; in addition, if debugging 117is enabled but debugging output is not directed to standard output, 118then the standard output is line buffered. 119.Ar Flags 120is one or more of the following: 121.Bl -tag -width Ds 122.It Ar A 123Print all possible debugging information; 124equivalent to specifying all of the debugging flags. 125.It Ar a 126Print debugging information about archive searching and caching. 127.It Ar C 128Print debugging information about current working directory. 129.It Ar c 130Print debugging information about conditional evaluation. 131.It Ar d 132Print debugging information about directory searching and caching. 133.It Ar e 134Print debugging information about failed commands and targets. 135.It Ar F Ns Oo Sy \&+ Oc Ns Ar filename 136Specify where debugging output is written. 137This must be the last flag, because it consumes the remainder of 138the argument. 139If the character immediately after the 140.Ql F 141flag is 142.Ql \&+ , 143then the file will be opened in append mode; 144otherwise the file will be overwritten. 145If the file name is 146.Ql stdout 147or 148.Ql stderr 149then debugging output will be written to the 150standard output or standard error output file descriptors respectively 151(and the 152.Ql \&+ 153option has no effect). 154Otherwise, the output will be written to the named file. 155If the file name ends 156.Ql .%d 157then the 158.Ql %d 159is replaced by the pid. 160.It Ar f 161Print debugging information about loop evaluation. 162.It Ar "g1" 163Print the input graph before making anything. 164.It Ar "g2" 165Print the input graph after making everything, or before exiting 166on error. 167.It Ar "g3" 168Print the input graph before exiting on error. 169.It Ar j 170Print debugging information about running multiple shells. 171.It Ar l 172Print commands in Makefiles regardless of whether or not they are prefixed by 173.Ql @ 174or other "quiet" flags. 175Also known as "loud" behavior. 176.It Ar M 177Print debugging information about "meta" mode decisions about targets. 178.It Ar m 179Print debugging information about making targets, including modification 180dates. 181.It Ar n 182Don't delete the temporary command scripts created when running commands. 183These temporary scripts are created in the directory 184referred to by the 185.Ev TMPDIR 186environment variable, or in 187.Pa /tmp 188if 189.Ev TMPDIR 190is unset or set to the empty string. 191The temporary scripts are created by 192.Xr mkstemp 3 , 193and have names of the form 194.Pa makeXXXXXX . 195.Em NOTE : 196This can create many files in 197.Ev TMPDIR 198or 199.Pa /tmp , 200so use with care. 201.It Ar p 202Print debugging information about makefile parsing. 203.It Ar s 204Print debugging information about suffix-transformation rules. 205.It Ar t 206Print debugging information about target list maintenance. 207.It Ar V 208Force the 209.Fl V 210option to print raw values of variables, overriding the default behavior 211set via 212.Va .MAKE.EXPAND_VARIABLES . 213.It Ar v 214Print debugging information about variable assignment. 215.It Ar x 216Run shell commands with 217.Fl x 218so the actual commands are printed as they are executed. 219.El 220.It Fl e 221Specify that environment variables override macro assignments within 222makefiles. 223.It Fl f Ar makefile 224Specify a makefile to read instead of the default 225.Ql Pa makefile . 226If 227.Ar makefile 228is 229.Ql Fl , 230standard input is read. 231Multiple makefiles may be specified, and are read in the order specified. 232.It Fl I Ar directory 233Specify a directory in which to search for makefiles and included makefiles. 234The system makefile directory (or directories, see the 235.Fl m 236option) is automatically included as part of this list. 237.It Fl i 238Ignore non-zero exit of shell commands in the makefile. 239Equivalent to specifying 240.Ql Fl 241before each command line in the makefile. 242.It Fl J Ar private 243This option should 244.Em not 245be specified by the user. 246.Pp 247When the 248.Ar j 249option is in use in a recursive build, this option is passed by a make 250to child makes to allow all the make processes in the build to 251cooperate to avoid overloading the system. 252.It Fl j Ar max_jobs 253Specify the maximum number of jobs that 254.Nm 255may have running at any one time. 256The value is saved in 257.Va .MAKE.JOBS . 258Turns compatibility mode off, unless the 259.Ar B 260flag is also specified. 261When compatibility mode is off, all commands associated with a 262target are executed in a single shell invocation as opposed to the 263traditional one shell invocation per line. 264This can break traditional scripts which change directories on each 265command invocation and then expect to start with a fresh environment 266on the next line. 267It is more efficient to correct the scripts rather than turn backwards 268compatibility on. 269.It Fl k 270Continue processing after errors are encountered, but only on those targets 271that do not depend on the target whose creation caused the error. 272.It Fl m Ar directory 273Specify a directory in which to search for sys.mk and makefiles included 274via the 275.Li \&< Ns Ar file Ns Li \&> Ns -style 276include statement. 277The 278.Fl m 279option can be used multiple times to form a search path. 280This path will override the default system include path: /usr/share/mk. 281Furthermore the system include path will be appended to the search path used 282for 283.Li \*q Ns Ar file Ns Li \*q Ns -style 284include statements (see the 285.Fl I 286option). 287.Pp 288If a file or directory name in the 289.Fl m 290argument (or the 291.Ev MAKESYSPATH 292environment variable) starts with the string 293.Qq \&.../ 294then 295.Nm 296will search for the specified file or directory named in the remaining part 297of the argument string. 298The search starts with the current directory of 299the Makefile and then works upward towards the root of the file system. 300If the search is successful, then the resulting directory replaces the 301.Qq \&.../ 302specification in the 303.Fl m 304argument. 305If used, this feature allows 306.Nm 307to easily search in the current source tree for customized sys.mk files 308(e.g., by using 309.Qq \&.../mk/sys.mk 310as an argument). 311.It Fl n 312Display the commands that would have been executed, but do not 313actually execute them unless the target depends on the .MAKE special 314source (see below). 315.It Fl N 316Display the commands which would have been executed, but do not 317actually execute any of them; useful for debugging top-level makefiles 318without descending into subdirectories. 319.It Fl q 320Do not execute any commands, but exit 0 if the specified targets are 321up-to-date and 1, otherwise. 322.It Fl r 323Do not use the built-in rules specified in the system makefile. 324.It Fl s 325Do not echo any commands as they are executed. 326Equivalent to specifying 327.Ql Ic @ 328before each command line in the makefile. 329.It Fl T Ar tracefile 330When used with the 331.Fl j 332flag, 333append a trace record to 334.Ar tracefile 335for each job started and completed. 336.It Fl t 337Rather than re-building a target as specified in the makefile, create it 338or update its modification time to make it appear up-to-date. 339.It Fl V Ar variable 340Print the value of 341.Ar variable . 342Do not build any targets. 343Multiple instances of this option may be specified; 344the variables will be printed one per line, 345with a blank line for each null or undefined variable. 346The value printed is extracted from the global context after all 347makefiles have been read. 348By default, the raw variable contents (which may 349include additional unexpanded variable references) are shown. 350If 351.Ar variable 352contains a 353.Ql \&$ 354then the value will be recursively expanded to its complete resultant 355text before printing. 356The expanded value will also be printed if 357.Va .MAKE.EXPAND_VARIABLES 358is set to true and 359the 360.Fl dV 361option has not been used to override it. 362Note that loop-local and target-local variables, as well as values 363taken temporarily by global variables during makefile processing, are 364not accessible via this option. 365The 366.Fl dv 367debug mode can be used to see these at the cost of generating 368substantial extraneous output. 369.It Fl v Ar variable 370Like 371.Fl V 372but the variable is always expanded to its complete value. 373.It Fl W 374Treat any warnings during makefile parsing as errors. 375.It Fl w 376Print entering and leaving directory messages, pre and post processing. 377.It Fl X 378Don't export variables passed on the command line to the environment 379individually. 380Variables passed on the command line are still exported 381via the 382.Va MAKEFLAGS 383environment variable. 384This option may be useful on systems which have a small limit on the 385size of command arguments. 386.It Ar variable=value 387Set the value of the variable 388.Ar variable 389to 390.Ar value . 391Normally, all values passed on the command line are also exported to 392sub-makes in the environment. 393The 394.Fl X 395flag disables this behavior. 396Variable assignments should follow options for POSIX compatibility 397but no ordering is enforced. 398.El 399.Pp 400There are seven different types of lines in a makefile: file dependency 401specifications, shell commands, variable assignments, include statements, 402conditional directives, for loops, and comments. 403.Pp 404In general, lines may be continued from one line to the next by ending 405them with a backslash 406.Pq Ql \e . 407The trailing newline character and initial whitespace on the following 408line are compressed into a single space. 409.Sh FILE DEPENDENCY SPECIFICATIONS 410Dependency lines consist of one or more targets, an operator, and zero 411or more sources. 412This creates a relationship where the targets 413.Dq depend 414on the sources 415and are usually created from them. 416The exact relationship between the target and the source is determined 417by the operator that separates them. 418The three operators are as follows: 419.Bl -tag -width flag 420.It Ic \&: 421A target is considered out-of-date if its modification time is less than 422those of any of its sources. 423Sources for a target accumulate over dependency lines when this operator 424is used. 425The target is removed if 426.Nm 427is interrupted. 428.It Ic \&! 429Targets are always re-created, but not until all sources have been 430examined and re-created as necessary. 431Sources for a target accumulate over dependency lines when this operator 432is used. 433The target is removed if 434.Nm 435is interrupted. 436.It Ic \&:: 437If no sources are specified, the target is always re-created. 438Otherwise, a target is considered out-of-date if any of its sources has 439been modified more recently than the target. 440Sources for a target do not accumulate over dependency lines when this 441operator is used. 442The target will not be removed if 443.Nm 444is interrupted. 445.El 446.Pp 447Targets and sources may contain the shell wildcard values 448.Ql \&? , 449.Ql * , 450.Ql [] , 451and 452.Ql {} . 453The values 454.Ql \&? , 455.Ql * , 456and 457.Ql [] 458may only be used as part of the final 459component of the target or source, and must be used to describe existing 460files. 461The value 462.Ql {} 463need not necessarily be used to describe existing files. 464Expansion is in directory order, not alphabetically as done in the shell. 465.Sh SHELL COMMANDS 466Each target may have associated with it one or more lines of shell 467commands, normally 468used to create the target. 469Each of the lines in this script 470.Em must 471be preceded by a tab. 472(For historical reasons, spaces are not accepted.) 473While targets can appear in many dependency lines if desired, by 474default only one of these rules may be followed by a creation 475script. 476If the 477.Ql Ic \&:: 478operator is used, however, all rules may include scripts and the 479scripts are executed in the order found. 480.Pp 481Each line is treated as a separate shell command, unless the end of 482line is escaped with a backslash 483.Pq Ql \e 484in which case that line and the next are combined. 485.\" The escaped newline is retained and passed to the shell, which 486.\" normally ignores it. 487.\" However, the tab at the beginning of the following line is removed. 488If the first characters of the command are any combination of 489.Ql Ic @ , 490.Ql Ic + , 491or 492.Ql Ic \- , 493the command is treated specially. 494A 495.Ql Ic @ 496causes the command not to be echoed before it is executed. 497A 498.Ql Ic + 499causes the command to be executed even when 500.Fl n 501is given. 502This is similar to the effect of the .MAKE special source, 503except that the effect can be limited to a single line of a script. 504A 505.Ql Ic \- 506in compatibility mode 507causes any non-zero exit status of the command line to be ignored. 508.Pp 509When 510.Nm 511is run in jobs mode with 512.Fl j Ar max_jobs , 513the entire script for the target is fed to a 514single instance of the shell. 515In compatibility (non-jobs) mode, each command is run in a separate process. 516If the command contains any shell meta characters 517.Pq Ql #=|^(){};&<>*?[]:$`\e\en 518it will be passed to the shell; otherwise 519.Nm 520will attempt direct execution. 521If a line starts with 522.Ql Ic \- 523and the shell has ErrCtl enabled then failure of the command line 524will be ignored as in compatibility mode. 525Otherwise 526.Ql Ic \- 527affects the entire job; 528the script will stop at the first command line that fails, 529but the target will not be deemed to have failed. 530.Pp 531Makefiles should be written so that the mode of 532.Nm 533operation does not change their behavior. 534For example, any command which needs to use 535.Dq cd 536or 537.Dq chdir 538without potentially changing the directory for subsequent commands 539should be put in parentheses so it executes in a subshell. 540To force the use of one shell, escape the line breaks so as to make 541the whole script one command. 542For example: 543.Bd -literal -offset indent 544avoid-chdir-side-effects: 545 @echo Building $@ in `pwd` 546 @(cd ${.CURDIR} && ${MAKE} $@) 547 @echo Back in `pwd` 548 549ensure-one-shell-regardless-of-mode: 550 @echo Building $@ in `pwd`; \e 551 (cd ${.CURDIR} && ${MAKE} $@); \e 552 echo Back in `pwd` 553.Ed 554.Pp 555Since 556.Nm 557will 558.Xr chdir 2 559to 560.Ql Va .OBJDIR 561before executing any targets, each child process 562starts with that as its current working directory. 563.Sh VARIABLE ASSIGNMENTS 564Variables in make are much like variables in the shell, and, by tradition, 565consist of all upper-case letters. 566.Ss Variable assignment modifiers 567The five operators that can be used to assign values to variables are as 568follows: 569.Bl -tag -width Ds 570.It Ic \&= 571Assign the value to the variable. 572Any previous value is overridden. 573.It Ic \&+= 574Append the value to the current value of the variable. 575.It Ic \&?= 576Assign the value to the variable if it is not already defined. 577.It Ic \&:= 578Assign with expansion, i.e. expand the value before assigning it 579to the variable. 580Normally, expansion is not done until the variable is referenced. 581.Em NOTE : 582References to undefined variables are 583.Em not 584expanded. 585This can cause problems when variable modifiers are used. 586.It Ic \&!= 587Expand the value and pass it to the shell for execution and assign 588the result to the variable. 589Any newlines in the result are replaced with spaces. 590.El 591.Pp 592Any white-space before the assigned 593.Ar value 594is removed; if the value is being appended, a single space is inserted 595between the previous contents of the variable and the appended value. 596.Pp 597Variables are expanded by surrounding the variable name with either 598curly braces 599.Pq Ql {} 600or parentheses 601.Pq Ql () 602and preceding it with 603a dollar sign 604.Pq Ql \&$ . 605If the variable name contains only a single letter, the surrounding 606braces or parentheses are not required. 607This shorter form is not recommended. 608.Pp 609If the variable name contains a dollar, then the name itself is expanded first. 610This allows almost arbitrary variable names, however names containing dollar, 611braces, parenthesis, or whitespace are really best avoided! 612.Pp 613If the result of expanding a variable contains a dollar sign 614.Pq Ql \&$ 615the string is expanded again. 616.Pp 617Variable substitution occurs at three distinct times, depending on where 618the variable is being used. 619.Bl -enum 620.It 621Variables in dependency lines are expanded as the line is read. 622.It 623Variables in shell commands are expanded when the shell command is 624executed. 625.It 626.Dq .for 627loop index variables are expanded on each loop iteration. 628Note that other variables are not expanded inside loops so 629the following example code: 630.Bd -literal -offset indent 631 632.Dv .for i in 1 2 3 633a+= ${i} 634j= ${i} 635b+= ${j} 636.Dv .endfor 637 638all: 639 @echo ${a} 640 @echo ${b} 641 642.Ed 643will print: 644.Bd -literal -offset indent 6451 2 3 6463 3 3 647 648.Ed 649Because while ${a} contains 650.Dq 1 2 3 651after the loop is executed, ${b} 652contains 653.Dq ${j} ${j} ${j} 654which expands to 655.Dq 3 3 3 656since after the loop completes ${j} contains 657.Dq 3 . 658.El 659.Ss Variable classes 660The four different classes of variables (in order of increasing precedence) 661are: 662.Bl -tag -width Ds 663.It Environment variables 664Variables defined as part of 665.Nm Ns 's 666environment. 667.It Global variables 668Variables defined in the makefile or in included makefiles. 669.It Command line variables 670Variables defined as part of the command line. 671.It Local variables 672Variables that are defined specific to a certain target. 673.El 674.Pp 675Local variables are all built in and their values vary magically from 676target to target. 677It is not currently possible to define new local variables. 678The seven local variables are as follows: 679.Bl -tag -width ".ARCHIVE" -offset indent 680.It Va .ALLSRC 681The list of all sources for this target; also known as 682.Ql Va \&> . 683.It Va .ARCHIVE 684The name of the archive file; also known as 685.Ql Va \&! . 686.It Va .IMPSRC 687In suffix-transformation rules, the name/path of the source from which the 688target is to be transformed (the 689.Dq implied 690source); also known as 691.Ql Va \&< . 692It is not defined in explicit rules. 693.It Va .MEMBER 694The name of the archive member; also known as 695.Ql Va % . 696.It Va .OODATE 697The list of sources for this target that were deemed out-of-date; also 698known as 699.Ql Va \&? . 700.It Va .PREFIX 701The file prefix of the target, containing only the file portion, no suffix 702or preceding directory components; also known as 703.Ql Va * . 704The suffix must be one of the known suffixes declared with 705.Ic .SUFFIXES 706or it will not be recognized. 707.It Va .TARGET 708The name of the target; also known as 709.Ql Va @ . 710For compatibility with other makes this is an alias for 711.Ic .ARCHIVE 712in archive member rules. 713.El 714.Pp 715The shorter forms 716.Ql ( Va > , 717.Ql Va \&! , 718.Ql Va < , 719.Ql Va % , 720.Ql Va \&? , 721.Ql Va * , 722and 723.Ql Va @ ) 724are permitted for backward 725compatibility with historical makefiles and legacy POSIX make and are 726not recommended. 727.Pp 728Variants of these variables with the punctuation followed immediately by 729.Ql D 730or 731.Ql F , 732e.g. 733.Ql Va $(@D) , 734are legacy forms equivalent to using the 735.Ql :H 736and 737.Ql :T 738modifiers. 739These forms are accepted for compatibility with 740.At V 741makefiles and POSIX but are not recommended. 742.Pp 743Four of the local variables may be used in sources on dependency lines 744because they expand to the proper value for each target on the line. 745These variables are 746.Ql Va .TARGET , 747.Ql Va .PREFIX , 748.Ql Va .ARCHIVE , 749and 750.Ql Va .MEMBER . 751.Ss Additional built-in variables 752In addition, 753.Nm 754sets or knows about the following variables: 755.Bl -tag -width .MAKEOVERRIDES 756.It Va \&$ 757A single dollar sign 758.Ql \&$ , 759i.e. 760.Ql \&$$ 761expands to a single dollar 762sign. 763.It Va .ALLTARGETS 764The list of all targets encountered in the Makefile. 765If evaluated during 766Makefile parsing, lists only those targets encountered thus far. 767.It Va .CURDIR 768A path to the directory where 769.Nm 770was executed. 771Refer to the description of 772.Ql Ev PWD 773for more details. 774.It Va .INCLUDEDFROMDIR 775The directory of the file this Makefile was included from. 776.It Va .INCLUDEDFROMFILE 777The filename of the file this Makefile was included from. 778.It Ev MAKE 779The name that 780.Nm 781was executed with 782.Pq Va argv[0] . 783For compatibility 784.Nm 785also sets 786.Va .MAKE 787with the same value. 788The preferred variable to use is the environment variable 789.Ev MAKE 790because it is more compatible with other versions of 791.Nm 792and cannot be confused with the special target with the same name. 793.It Va .MAKE.DEPENDFILE 794Names the makefile (default 795.Ql Pa .depend ) 796from which generated dependencies are read. 797.It Va .MAKE.EXPAND_VARIABLES 798A boolean that controls the default behavior of the 799.Fl V 800option. 801If true, variable values printed with 802.Fl V 803are fully expanded; if false, the raw variable contents (which may 804include additional unexpanded variable references) are shown. 805.It Va .MAKE.EXPORTED 806The list of variables exported by 807.Nm . 808.It Va .MAKE.JOBS 809The argument to the 810.Fl j 811option. 812.It Va .MAKE.JOB.PREFIX 813If 814.Nm 815is run with 816.Ar j 817then output for each target is prefixed with a token 818.Ql --- target --- 819the first part of which can be controlled via 820.Va .MAKE.JOB.PREFIX . 821If 822.Va .MAKE.JOB.PREFIX 823is empty, no token is printed. 824.br 825For example: 826.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}] 827would produce tokens like 828.Ql ---make[1234] target --- 829making it easier to track the degree of parallelism being achieved. 830.It Ev MAKEFLAGS 831The environment variable 832.Ql Ev MAKEFLAGS 833may contain anything that 834may be specified on 835.Nm Ns 's 836command line. 837Anything specified on 838.Nm Ns 's 839command line is appended to the 840.Ql Ev MAKEFLAGS 841variable which is then 842entered into the environment for all programs which 843.Nm 844executes. 845.It Va .MAKE.LEVEL 846The recursion depth of 847.Nm . 848The initial instance of 849.Nm 850will be 0, and an incremented value is put into the environment 851to be seen by the next generation. 852This allows tests like: 853.Li .if ${.MAKE.LEVEL} == 0 854to protect things which should only be evaluated in the initial instance of 855.Nm . 856.It Va .MAKE.MAKEFILE_PREFERENCE 857The ordered list of makefile names 858(default 859.Ql Pa makefile , 860.Ql Pa Makefile ) 861that 862.Nm 863will look for. 864.It Va .MAKE.MAKEFILES 865The list of makefiles read by 866.Nm , 867which is useful for tracking dependencies. 868Each makefile is recorded only once, regardless of the number of times read. 869.It Va .MAKE.MODE 870Processed after reading all makefiles. 871Can affect the mode that 872.Nm 873runs in. 874It can contain a number of keywords: 875.Bl -hang -width missing-filemon=bf. 876.It Pa compat 877Like 878.Fl B , 879puts 880.Nm 881into "compat" mode. 882.It Pa meta 883Puts 884.Nm 885into "meta" mode, where meta files are created for each target 886to capture the command run, the output generated and if 887.Xr filemon 4 888is available, the system calls which are of interest to 889.Nm . 890The captured output can be very useful when diagnosing errors. 891.It Pa curdirOk= Ar bf 892Normally 893.Nm 894will not create .meta files in 895.Ql Va .CURDIR . 896This can be overridden by setting 897.Va bf 898to a value which represents True. 899.It Pa missing-meta= Ar bf 900If 901.Va bf 902is True, then a missing .meta file makes the target out-of-date. 903.It Pa missing-filemon= Ar bf 904If 905.Va bf 906is True, then missing filemon data makes the target out-of-date. 907.It Pa nofilemon 908Do not use 909.Xr filemon 4 . 910.It Pa env 911For debugging, it can be useful to include the environment 912in the .meta file. 913.It Pa verbose 914If in "meta" mode, print a clue about the target being built. 915This is useful if the build is otherwise running silently. 916The message printed the value of: 917.Va .MAKE.META.PREFIX . 918.It Pa ignore-cmd 919Some makefiles have commands which are simply not stable. 920This keyword causes them to be ignored for 921determining whether a target is out of date in "meta" mode. 922See also 923.Ic .NOMETA_CMP . 924.It Pa silent= Ar bf 925If 926.Va bf 927is True, when a .meta file is created, mark the target 928.Ic .SILENT . 929.El 930.It Va .MAKE.META.BAILIWICK 931In "meta" mode, provides a list of prefixes which 932match the directories controlled by 933.Nm . 934If a file that was generated outside of 935.Va .OBJDIR 936but within said bailiwick is missing, 937the current target is considered out-of-date. 938.It Va .MAKE.META.CREATED 939In "meta" mode, this variable contains a list of all the meta files 940updated. 941If not empty, it can be used to trigger processing of 942.Va .MAKE.META.FILES . 943.It Va .MAKE.META.FILES 944In "meta" mode, this variable contains a list of all the meta files 945used (updated or not). 946This list can be used to process the meta files to extract dependency 947information. 948.It Va .MAKE.META.IGNORE_PATHS 949Provides a list of path prefixes that should be ignored; 950because the contents are expected to change over time. 951The default list includes: 952.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp 953.It Va .MAKE.META.IGNORE_PATTERNS 954Provides a list of patterns to match against pathnames. 955Ignore any that match. 956.It Va .MAKE.META.IGNORE_FILTER 957Provides a list of variable modifiers to apply to each pathname. 958Ignore if the expansion is an empty string. 959.It Va .MAKE.META.PREFIX 960Defines the message printed for each meta file updated in "meta verbose" mode. 961The default value is: 962.Dl Building ${.TARGET:H:tA}/${.TARGET:T} 963.It Va .MAKEOVERRIDES 964This variable is used to record the names of variables assigned to 965on the command line, so that they may be exported as part of 966.Ql Ev MAKEFLAGS . 967This behavior can be disabled by assigning an empty value to 968.Ql Va .MAKEOVERRIDES 969within a makefile. 970Extra variables can be exported from a makefile 971by appending their names to 972.Ql Va .MAKEOVERRIDES . 973.Ql Ev MAKEFLAGS 974is re-exported whenever 975.Ql Va .MAKEOVERRIDES 976is modified. 977.It Va .MAKE.PATH_FILEMON 978If 979.Nm 980was built with 981.Xr filemon 4 982support, this is set to the path of the device node. 983This allows makefiles to test for this support. 984.It Va .MAKE.PID 985The process-id of 986.Nm . 987.It Va .MAKE.PPID 988The parent process-id of 989.Nm . 990.It Va .MAKE.SAVE_DOLLARS 991value should be a boolean that controls whether 992.Ql $$ 993are preserved when doing 994.Ql := 995assignments. 996The default is false, for backwards compatibility. 997Set to true for compatability with other makes. 998If set to false, 999.Ql $$ 1000becomes 1001.Ql $ 1002per normal evaluation rules. 1003.It Va MAKE_PRINT_VAR_ON_ERROR 1004When 1005.Nm 1006stops due to an error, it sets 1007.Ql Va .ERROR_TARGET 1008to the name of the target that failed, 1009.Ql Va .ERROR_CMD 1010to the commands of the failed target, 1011and in "meta" mode, it also sets 1012.Ql Va .ERROR_CWD 1013to the 1014.Xr getcwd 3 , 1015and 1016.Ql Va .ERROR_META_FILE 1017to the path of the meta file (if any) describing the failed target. 1018It then prints its name and the value of 1019.Ql Va .CURDIR 1020as well as the value of any variables named in 1021.Ql Va MAKE_PRINT_VAR_ON_ERROR . 1022.It Va .newline 1023This variable is simply assigned a newline character as its value. 1024This allows expansions using the 1025.Cm \&:@ 1026modifier to put a newline between 1027iterations of the loop rather than a space. 1028For example, the printing of 1029.Ql Va MAKE_PRINT_VAR_ON_ERROR 1030could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}. 1031.It Va .OBJDIR 1032A path to the directory where the targets are built. 1033Its value is determined by trying to 1034.Xr chdir 2 1035to the following directories in order and using the first match: 1036.Bl -enum 1037.It 1038.Ev ${MAKEOBJDIRPREFIX}${.CURDIR} 1039.Pp 1040(Only if 1041.Ql Ev MAKEOBJDIRPREFIX 1042is set in the environment or on the command line.) 1043.It 1044.Ev ${MAKEOBJDIR} 1045.Pp 1046(Only if 1047.Ql Ev MAKEOBJDIR 1048is set in the environment or on the command line.) 1049.It 1050.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE} 1051.It 1052.Ev ${.CURDIR} Ns Pa /obj 1053.It 1054.Pa /usr/obj/ Ns Ev ${.CURDIR} 1055.It 1056.Ev ${.CURDIR} 1057.El 1058.Pp 1059Variable expansion is performed on the value before it's used, 1060so expressions such as 1061.Dl ${.CURDIR:S,^/usr/src,/var/obj,} 1062may be used. 1063This is especially useful with 1064.Ql Ev MAKEOBJDIR . 1065.Pp 1066.Ql Va .OBJDIR 1067may be modified in the makefile via the special target 1068.Ql Ic .OBJDIR . 1069In all cases, 1070.Nm 1071will 1072.Xr chdir 2 1073to the specified directory if it exists, and set 1074.Ql Va .OBJDIR 1075and 1076.Ql Ev PWD 1077to that directory before executing any targets. 1078. 1079.It Va .PARSEDIR 1080A path to the directory of the current 1081.Ql Pa Makefile 1082being parsed. 1083.It Va .PARSEFILE 1084The basename of the current 1085.Ql Pa Makefile 1086being parsed. 1087This variable and 1088.Ql Va .PARSEDIR 1089are both set only while the 1090.Ql Pa Makefiles 1091are being parsed. 1092If you want to retain their current values, assign them to a variable 1093using assignment with expansion: 1094.Pq Ql Cm \&:= . 1095.It Va .PATH 1096A variable that represents the list of directories that 1097.Nm 1098will search for files. 1099The search list should be updated using the target 1100.Ql Va .PATH 1101rather than the variable. 1102.It Ev PWD 1103Alternate path to the current directory. 1104.Nm 1105normally sets 1106.Ql Va .CURDIR 1107to the canonical path given by 1108.Xr getcwd 3 . 1109However, if the environment variable 1110.Ql Ev PWD 1111is set and gives a path to the current directory, then 1112.Nm 1113sets 1114.Ql Va .CURDIR 1115to the value of 1116.Ql Ev PWD 1117instead. 1118This behavior is disabled if 1119.Ql Ev MAKEOBJDIRPREFIX 1120is set or 1121.Ql Ev MAKEOBJDIR 1122contains a variable transform. 1123.Ql Ev PWD 1124is set to the value of 1125.Ql Va .OBJDIR 1126for all programs which 1127.Nm 1128executes. 1129.It Ev .TARGETS 1130The list of targets explicitly specified on the command line, if any. 1131.It Ev VPATH 1132Colon-separated 1133.Pq Dq \&: 1134lists of directories that 1135.Nm 1136will search for files. 1137The variable is supported for compatibility with old make programs only, 1138use 1139.Ql Va .PATH 1140instead. 1141.El 1142.Ss Variable modifiers 1143Variable expansion may be modified to select or modify each word of the 1144variable (where a 1145.Dq word 1146is white-space delimited sequence of characters). 1147The general format of a variable expansion is as follows: 1148.Pp 1149.Dl ${variable[:modifier[:...]]} 1150.Pp 1151Each modifier begins with a colon, 1152which may be escaped with a backslash 1153.Pq Ql \e . 1154.Pp 1155A set of modifiers can be specified via a variable, as follows: 1156.Pp 1157.Dl modifier_variable=modifier[:...] 1158.Dl ${variable:${modifier_variable}[:...]} 1159.Pp 1160In this case the first modifier in the modifier_variable does not 1161start with a colon, since that must appear in the referencing 1162variable. 1163If any of the modifiers in the modifier_variable contain a dollar sign 1164.Pq Ql $ , 1165these must be doubled to avoid early expansion. 1166.Pp 1167The supported modifiers are: 1168.Bl -tag -width EEE 1169.It Cm \&:E 1170Replaces each word in the variable with its suffix. 1171.It Cm \&:H 1172Replaces each word in the variable with everything but the last component. 1173.It Cm \&:M Ns Ar pattern 1174Select only those words that match 1175.Ar pattern . 1176The standard shell wildcard characters 1177.Pf ( Ql * , 1178.Ql \&? , 1179and 1180.Ql Oo Oc ) 1181may 1182be used. 1183The wildcard characters may be escaped with a backslash 1184.Pq Ql \e . 1185As a consequence of the way values are split into words, matched, 1186and then joined, a construct like 1187.Dl ${VAR:M*} 1188will normalize the inter-word spacing, removing all leading and 1189trailing space, and converting multiple consecutive spaces 1190to single spaces. 1191. 1192.It Cm \&:N Ns Ar pattern 1193This is identical to 1194.Ql Cm \&:M , 1195but selects all words which do not match 1196.Ar pattern . 1197.It Cm \&:O 1198Order every word in variable alphabetically. 1199.It Cm \&:Or 1200Order every word in variable in reverse alphabetical order. 1201.It Cm \&:Ox 1202Randomize words in variable. 1203The results will be different each time you are referring to the 1204modified variable; use the assignment with expansion 1205.Pq Ql Cm \&:= 1206to prevent such behavior. 1207For example, 1208.Bd -literal -offset indent 1209LIST= uno due tre quattro 1210RANDOM_LIST= ${LIST:Ox} 1211STATIC_RANDOM_LIST:= ${LIST:Ox} 1212 1213all: 1214 @echo "${RANDOM_LIST}" 1215 @echo "${RANDOM_LIST}" 1216 @echo "${STATIC_RANDOM_LIST}" 1217 @echo "${STATIC_RANDOM_LIST}" 1218.Ed 1219may produce output similar to: 1220.Bd -literal -offset indent 1221quattro due tre uno 1222tre due quattro uno 1223due uno quattro tre 1224due uno quattro tre 1225.Ed 1226.It Cm \&:Q 1227Quotes every shell meta-character in the variable, so that it can be passed 1228safely to the shell. 1229.It Cm \&:q 1230Quotes every shell meta-character in the variable, and also doubles 1231.Sq $ 1232characters so that it can be passed 1233safely through recursive invocations of 1234.Nm . 1235This is equivalent to: 1236.Sq \&:S/\e\&$/&&/g:Q . 1237.It Cm \&:R 1238Replaces each word in the variable with everything but its suffix. 1239.It Cm \&:range[=count] 1240The value is an integer sequence representing the words of the original 1241value, or the supplied 1242.Va count . 1243.It Cm \&:gmtime[=utc] 1244The value is a format string for 1245.Xr strftime 3 , 1246using 1247.Xr gmtime 3 . 1248If a 1249.Va utc 1250value is not provided or is 0, the current time is used. 1251.It Cm \&:hash 1252Compute a 32-bit hash of the value and encode it as hex digits. 1253.It Cm \&:localtime[=utc] 1254The value is a format string for 1255.Xr strftime 3 , 1256using 1257.Xr localtime 3 . 1258If a 1259.Va utc 1260value is not provided or is 0, the current time is used. 1261.It Cm \&:tA 1262Attempt to convert variable to an absolute path using 1263.Xr realpath 3 , 1264if that fails, the value is unchanged. 1265.It Cm \&:tl 1266Converts variable to lower-case letters. 1267.It Cm \&:ts Ns Ar c 1268Words in the variable are normally separated by a space on expansion. 1269This modifier sets the separator to the character 1270.Ar c . 1271If 1272.Ar c 1273is omitted, then no separator is used. 1274The common escapes (including octal numeric codes), work as expected. 1275.It Cm \&:tu 1276Converts variable to upper-case letters. 1277.It Cm \&:tW 1278Causes the value to be treated as a single word 1279(possibly containing embedded white space). 1280See also 1281.Ql Cm \&:[*] . 1282.It Cm \&:tw 1283Causes the value to be treated as a sequence of 1284words delimited by white space. 1285See also 1286.Ql Cm \&:[@] . 1287.Sm off 1288.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW 1289.Sm on 1290Modify the first occurrence of 1291.Ar old_string 1292in the variable's value, replacing it with 1293.Ar new_string . 1294If a 1295.Ql g 1296is appended to the last slash of the pattern, all occurrences 1297in each word are replaced. 1298If a 1299.Ql 1 1300is appended to the last slash of the pattern, only the first word 1301is affected. 1302If a 1303.Ql W 1304is appended to the last slash of the pattern, 1305then the value is treated as a single word 1306(possibly containing embedded white space). 1307If 1308.Ar old_string 1309begins with a caret 1310.Pq Ql ^ , 1311.Ar old_string 1312is anchored at the beginning of each word. 1313If 1314.Ar old_string 1315ends with a dollar sign 1316.Pq Ql \&$ , 1317it is anchored at the end of each word. 1318Inside 1319.Ar new_string , 1320an ampersand 1321.Pq Ql & 1322is replaced by 1323.Ar old_string 1324(without any 1325.Ql ^ 1326or 1327.Ql \&$ ) . 1328Any character may be used as a delimiter for the parts of the modifier 1329string. 1330The anchoring, ampersand and delimiter characters may be escaped with a 1331backslash 1332.Pq Ql \e . 1333.Pp 1334Variable expansion occurs in the normal fashion inside both 1335.Ar old_string 1336and 1337.Ar new_string 1338with the single exception that a backslash is used to prevent the expansion 1339of a dollar sign 1340.Pq Ql \&$ , 1341not a preceding dollar sign as is usual. 1342.Sm off 1343.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW 1344.Sm on 1345The 1346.Cm \&:C 1347modifier is just like the 1348.Cm \&:S 1349modifier except that the old and new strings, instead of being 1350simple strings, are an extended regular expression (see 1351.Xr regex 3 ) 1352string 1353.Ar pattern 1354and an 1355.Xr ed 1 Ns \-style 1356string 1357.Ar replacement . 1358Normally, the first occurrence of the pattern 1359.Ar pattern 1360in each word of the value is substituted with 1361.Ar replacement . 1362The 1363.Ql 1 1364modifier causes the substitution to apply to at most one word; the 1365.Ql g 1366modifier causes the substitution to apply to as many instances of the 1367search pattern 1368.Ar pattern 1369as occur in the word or words it is found in; the 1370.Ql W 1371modifier causes the value to be treated as a single word 1372(possibly containing embedded white space). 1373Note that 1374.Ql 1 1375and 1376.Ql g 1377are orthogonal; the former specifies whether multiple words are 1378potentially affected, the latter whether multiple substitutions can 1379potentially occur within each affected word. 1380.Pp 1381As for the 1382.Cm \&:S 1383modifier, the 1384.Ar pattern 1385and 1386.Ar replacement 1387are subjected to variable expansion before being parsed as 1388regular expressions. 1389.It Cm \&:T 1390Replaces each word in the variable with its last component. 1391.It Cm \&:u 1392Remove adjacent duplicate words (like 1393.Xr uniq 1 ) . 1394.Sm off 1395.It Cm \&:\&? Ar true_string Cm \&: Ar false_string 1396.Sm on 1397If the variable name (not its value), when parsed as a .if conditional 1398expression, evaluates to true, return as its value the 1399.Ar true_string , 1400otherwise return the 1401.Ar false_string . 1402Since the variable name is used as the expression, \&:\&? must be the 1403first modifier after the variable name itself - which will, of course, 1404usually contain variable expansions. 1405A common error is trying to use expressions like 1406.Dl ${NUMBERS:M42:?match:no} 1407which actually tests defined(NUMBERS), 1408to determine is any words match "42" you need to use something like: 1409.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} . 1410.It Ar :old_string=new_string 1411This is the 1412.At V 1413style variable substitution. 1414It must be the last modifier specified. 1415If 1416.Ar old_string 1417or 1418.Ar new_string 1419do not contain the pattern matching character 1420.Ar % 1421then it is assumed that they are 1422anchored at the end of each word, so only suffixes or entire 1423words may be replaced. 1424Otherwise 1425.Ar % 1426is the substring of 1427.Ar old_string 1428to be replaced in 1429.Ar new_string . 1430If only 1431.Ar old_string 1432contains the pattern matching character 1433.Ar % , 1434and 1435.Ar old_string 1436matches, then the result is the 1437.Ar new_string . 1438If only the 1439.Ar new_string 1440contains the pattern matching character 1441.Ar % , 1442then it is not treated specially and it is printed as a literal 1443.Ar % 1444on match. 1445If there is more than one pattern matching character 1446.Ar ( % ) 1447in either the 1448.Ar new_string 1449or 1450.Ar old_string , 1451only the first instance is treated specially (as the pattern character); 1452all subsequent instances are treated as regular characters 1453.Pp 1454Variable expansion occurs in the normal fashion inside both 1455.Ar old_string 1456and 1457.Ar new_string 1458with the single exception that a backslash is used to prevent the 1459expansion of a dollar sign 1460.Pq Ql \&$ , 1461not a preceding dollar sign as is usual. 1462.Sm off 1463.It Cm \&:@ Ar temp Cm @ Ar string Cm @ 1464.Sm on 1465This is the loop expansion mechanism from the OSF Development 1466Environment (ODE) make. 1467Unlike 1468.Cm \&.for 1469loops expansion occurs at the time of 1470reference. 1471Assign 1472.Ar temp 1473to each word in the variable and evaluate 1474.Ar string . 1475The ODE convention is that 1476.Ar temp 1477should start and end with a period. 1478For example. 1479.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@} 1480.Pp 1481However a single character variable is often more readable: 1482.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@} 1483.It Cm \&:_[=var] 1484Save the current variable value in 1485.Ql $_ 1486or the named 1487.Va var 1488for later reference. 1489Example usage: 1490.Bd -literal -offset indent 1491M_cmpv.units = 1 1000 1000000 1492M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\ 1493\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh 1494 1495.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}} 1496 1497.Ed 1498Here 1499.Ql $_ 1500is used to save the result of the 1501.Ql :S 1502modifier which is later referenced using the index values from 1503.Ql :range . 1504.It Cm \&:U Ns Ar newval 1505If the variable is undefined 1506.Ar newval 1507is the value. 1508If the variable is defined, the existing value is returned. 1509This is another ODE make feature. 1510It is handy for setting per-target CFLAGS for instance: 1511.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}} 1512If a value is only required if the variable is undefined, use: 1513.Dl ${VAR:D:Unewval} 1514.It Cm \&:D Ns Ar newval 1515If the variable is defined 1516.Ar newval 1517is the value. 1518.It Cm \&:L 1519The name of the variable is the value. 1520.It Cm \&:P 1521The path of the node which has the same name as the variable 1522is the value. 1523If no such node exists or its path is null, then the 1524name of the variable is used. 1525In order for this modifier to work, the name (node) must at least have 1526appeared on the rhs of a dependency. 1527.Sm off 1528.It Cm \&:\&! Ar cmd Cm \&! 1529.Sm on 1530The output of running 1531.Ar cmd 1532is the value. 1533.It Cm \&:sh 1534If the variable is non-empty it is run as a command and the output 1535becomes the new value. 1536.It Cm \&::= Ns Ar str 1537The variable is assigned the value 1538.Ar str 1539after substitution. 1540This modifier and its variations are useful in 1541obscure situations such as wanting to set a variable when shell commands 1542are being parsed. 1543These assignment modifiers always expand to 1544nothing, so if appearing in a rule line by themselves should be 1545preceded with something to keep 1546.Nm 1547happy. 1548.Pp 1549The 1550.Ql Cm \&:: 1551helps avoid false matches with the 1552.At V 1553style 1554.Cm \&:= 1555modifier and since substitution always occurs the 1556.Cm \&::= 1557form is vaguely appropriate. 1558.It Cm \&::?= Ns Ar str 1559As for 1560.Cm \&::= 1561but only if the variable does not already have a value. 1562.It Cm \&::+= Ns Ar str 1563Append 1564.Ar str 1565to the variable. 1566.It Cm \&::!= Ns Ar cmd 1567Assign the output of 1568.Ar cmd 1569to the variable. 1570.It Cm \&:\&[ Ns Ar range Ns Cm \&] 1571Selects one or more words from the value, 1572or performs other operations related to the way in which the 1573value is divided into words. 1574.Pp 1575Ordinarily, a value is treated as a sequence of words 1576delimited by white space. 1577Some modifiers suppress this behavior, 1578causing a value to be treated as a single word 1579(possibly containing embedded white space). 1580An empty value, or a value that consists entirely of white-space, 1581is treated as a single word. 1582For the purposes of the 1583.Ql Cm \&:[] 1584modifier, the words are indexed both forwards using positive integers 1585(where index 1 represents the first word), 1586and backwards using negative integers 1587(where index \-1 represents the last word). 1588.Pp 1589The 1590.Ar range 1591is subjected to variable expansion, and the expanded result is 1592then interpreted as follows: 1593.Bl -tag -width index 1594.\" :[n] 1595.It Ar index 1596Selects a single word from the value. 1597.\" :[start..end] 1598.It Ar start Ns Cm \&.. Ns Ar end 1599Selects all words from 1600.Ar start 1601to 1602.Ar end , 1603inclusive. 1604For example, 1605.Ql Cm \&:[2..-1] 1606selects all words from the second word to the last word. 1607If 1608.Ar start 1609is greater than 1610.Ar end , 1611then the words are output in reverse order. 1612For example, 1613.Ql Cm \&:[-1..1] 1614selects all the words from last to first. 1615If the list is already ordered, then this effectively reverses 1616the list, but it is more efficient to use 1617.Ql Cm \&:Or 1618instead of 1619.Ql Cm \&:O:[-1..1] . 1620.\" :[*] 1621.It Cm \&* 1622Causes subsequent modifiers to treat the value as a single word 1623(possibly containing embedded white space). 1624Analogous to the effect of 1625\&"$*\&" 1626in Bourne shell. 1627.\" :[0] 1628.It 0 1629Means the same as 1630.Ql Cm \&:[*] . 1631.\" :[*] 1632.It Cm \&@ 1633Causes subsequent modifiers to treat the value as a sequence of words 1634delimited by white space. 1635Analogous to the effect of 1636\&"$@\&" 1637in Bourne shell. 1638.\" :[#] 1639.It Cm \&# 1640Returns the number of words in the value. 1641.El \" :[range] 1642.El 1643.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS 1644Makefile inclusion, conditional structures and for loops reminiscent 1645of the C programming language are provided in 1646.Nm . 1647All such structures are identified by a line beginning with a single 1648dot 1649.Pq Ql \&. 1650character. 1651Files are included with either 1652.Cm \&.include \&< Ns Ar file Ns Cm \&> 1653or 1654.Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q . 1655Variables between the angle brackets or double quotes are expanded 1656to form the file name. 1657If angle brackets are used, the included makefile is expected to be in 1658the system makefile directory. 1659If double quotes are used, the including makefile's directory and any 1660directories specified using the 1661.Fl I 1662option are searched before the system 1663makefile directory. 1664For compatibility with other versions of 1665.Nm 1666.Ql include file ... 1667is also accepted. 1668.Pp 1669If the include statement is written as 1670.Cm .-include 1671or as 1672.Cm .sinclude 1673then errors locating and/or opening include files are ignored. 1674.Pp 1675If the include statement is written as 1676.Cm .dinclude 1677not only are errors locating and/or opening include files ignored, 1678but stale dependencies within the included file will be ignored 1679just like 1680.Va .MAKE.DEPENDFILE . 1681.Pp 1682Conditional expressions are also preceded by a single dot as the first 1683character of a line. 1684The possible conditionals are as follows: 1685.Bl -tag -width Ds 1686.It Ic .error Ar message 1687The message is printed along with the name of the makefile and line number, 1688then 1689.Nm 1690will exit. 1691.It Ic .export Ar variable ... 1692Export the specified global variable. 1693If no variable list is provided, all globals are exported 1694except for internal variables (those that start with 1695.Ql \&. ) . 1696This is not affected by the 1697.Fl X 1698flag, so should be used with caution. 1699For compatibility with other 1700.Nm 1701programs 1702.Ql export variable=value 1703is also accepted. 1704.Pp 1705Appending a variable name to 1706.Va .MAKE.EXPORTED 1707is equivalent to exporting a variable. 1708.It Ic .export-env Ar variable ... 1709The same as 1710.Ql .export , 1711except that the variable is not appended to 1712.Va .MAKE.EXPORTED . 1713This allows exporting a value to the environment which is different from that 1714used by 1715.Nm 1716internally. 1717.It Ic .export-literal Ar variable ... 1718The same as 1719.Ql .export-env , 1720except that variables in the value are not expanded. 1721.It Ic .info Ar message 1722The message is printed along with the name of the makefile and line number. 1723.It Ic .undef Ar variable 1724Un-define the specified global variable. 1725Only global variables may be un-defined. 1726.It Ic .unexport Ar variable ... 1727The opposite of 1728.Ql .export . 1729The specified global 1730.Va variable 1731will be removed from 1732.Va .MAKE.EXPORTED . 1733If no variable list is provided, all globals are unexported, 1734and 1735.Va .MAKE.EXPORTED 1736deleted. 1737.It Ic .unexport-env 1738Unexport all globals previously exported and 1739clear the environment inherited from the parent. 1740This operation will cause a memory leak of the original environment, 1741so should be used sparingly. 1742Testing for 1743.Va .MAKE.LEVEL 1744being 0, would make sense. 1745Also note that any variables which originated in the parent environment 1746should be explicitly preserved if desired. 1747For example: 1748.Bd -literal -offset indent 1749.Li .if ${.MAKE.LEVEL} == 0 1750PATH := ${PATH} 1751.Li .unexport-env 1752.Li .export PATH 1753.Li .endif 1754.Pp 1755.Ed 1756Would result in an environment containing only 1757.Ql Ev PATH , 1758which is the minimal useful environment. 1759Actually 1760.Ql Ev .MAKE.LEVEL 1761will also be pushed into the new environment. 1762.It Ic .warning Ar message 1763The message prefixed by 1764.Ql Pa warning: 1765is printed along with the name of the makefile and line number. 1766.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ... 1767Test the value of an expression. 1768.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1769Test the value of a variable. 1770.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1771Test the value of a variable. 1772.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1773Test the target being built. 1774.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ... 1775Test the target being built. 1776.It Ic .else 1777Reverse the sense of the last conditional. 1778.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ... 1779A combination of 1780.Ql Ic .else 1781followed by 1782.Ql Ic .if . 1783.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1784A combination of 1785.Ql Ic .else 1786followed by 1787.Ql Ic .ifdef . 1788.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1789A combination of 1790.Ql Ic .else 1791followed by 1792.Ql Ic .ifndef . 1793.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1794A combination of 1795.Ql Ic .else 1796followed by 1797.Ql Ic .ifmake . 1798.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1799A combination of 1800.Ql Ic .else 1801followed by 1802.Ql Ic .ifnmake . 1803.It Ic .endif 1804End the body of the conditional. 1805.El 1806.Pp 1807The 1808.Ar operator 1809may be any one of the following: 1810.Bl -tag -width "Cm XX" 1811.It Cm \&|\&| 1812Logical OR. 1813.It Cm \&&& 1814Logical 1815.Tn AND ; 1816of higher precedence than 1817.Dq \&|\&| . 1818.El 1819.Pp 1820As in C, 1821.Nm 1822will only evaluate a conditional as far as is necessary to determine 1823its value. 1824Parentheses may be used to change the order of evaluation. 1825The boolean operator 1826.Ql Ic \&! 1827may be used to logically negate an entire 1828conditional. 1829It is of higher precedence than 1830.Ql Ic \&&& . 1831.Pp 1832The value of 1833.Ar expression 1834may be any of the following: 1835.Bl -tag -width defined 1836.It Ic defined 1837Takes a variable name as an argument and evaluates to true if the variable 1838has been defined. 1839.It Ic make 1840Takes a target name as an argument and evaluates to true if the target 1841was specified as part of 1842.Nm Ns 's 1843command line or was declared the default target (either implicitly or 1844explicitly, see 1845.Va .MAIN ) 1846before the line containing the conditional. 1847.It Ic empty 1848Takes a variable, with possible modifiers, and evaluates to true if 1849the expansion of the variable would result in an empty string. 1850.It Ic exists 1851Takes a file name as an argument and evaluates to true if the file exists. 1852The file is searched for on the system search path (see 1853.Va .PATH ) . 1854.It Ic target 1855Takes a target name as an argument and evaluates to true if the target 1856has been defined. 1857.It Ic commands 1858Takes a target name as an argument and evaluates to true if the target 1859has been defined and has commands associated with it. 1860.El 1861.Pp 1862.Ar Expression 1863may also be an arithmetic or string comparison. 1864Variable expansion is 1865performed on both sides of the comparison, after which the integral 1866values are compared. 1867A value is interpreted as hexadecimal if it is 1868preceded by 0x, otherwise it is decimal; octal numbers are not supported. 1869The standard C relational operators are all supported. 1870If after 1871variable expansion, either the left or right hand side of a 1872.Ql Ic == 1873or 1874.Ql Ic "!=" 1875operator is not an integral value, then 1876string comparison is performed between the expanded 1877variables. 1878If no relational operator is given, it is assumed that the expanded 1879variable is being compared against 0 or an empty string in the case 1880of a string comparison. 1881.Pp 1882When 1883.Nm 1884is evaluating one of these conditional expressions, and it encounters 1885a (white-space separated) word it doesn't recognize, either the 1886.Dq make 1887or 1888.Dq defined 1889expression is applied to it, depending on the form of the conditional. 1890If the form is 1891.Ql Ic .ifdef , 1892.Ql Ic .ifndef , 1893or 1894.Ql Ic .if 1895the 1896.Dq defined 1897expression is applied. 1898Similarly, if the form is 1899.Ql Ic .ifmake 1900or 1901.Ql Ic .ifnmake , 1902the 1903.Dq make 1904expression is applied. 1905.Pp 1906If the conditional evaluates to true the parsing of the makefile continues 1907as before. 1908If it evaluates to false, the following lines are skipped. 1909In both cases this continues until a 1910.Ql Ic .else 1911or 1912.Ql Ic .endif 1913is found. 1914.Pp 1915For loops are typically used to apply a set of rules to a list of files. 1916The syntax of a for loop is: 1917.Pp 1918.Bl -tag -compact -width Ds 1919.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression 1920.It Aq make-rules 1921.It Ic \&.endfor 1922.El 1923.Pp 1924After the for 1925.Ic expression 1926is evaluated, it is split into words. 1927On each iteration of the loop, one word is taken and assigned to each 1928.Ic variable , 1929in order, and these 1930.Ic variables 1931are substituted into the 1932.Ic make-rules 1933inside the body of the for loop. 1934The number of words must come out even; that is, if there are three 1935iteration variables, the number of words provided must be a multiple 1936of three. 1937.Sh COMMENTS 1938Comments begin with a hash 1939.Pq Ql \&# 1940character, anywhere but in a shell 1941command line, and continue to the end of an unescaped new line. 1942.Sh SPECIAL SOURCES (ATTRIBUTES) 1943.Bl -tag -width .IGNOREx 1944.It Ic .EXEC 1945Target is never out of date, but always execute commands anyway. 1946.It Ic .IGNORE 1947Ignore any errors from the commands associated with this target, exactly 1948as if they all were preceded by a dash 1949.Pq Ql \- . 1950.\" .It Ic .INVISIBLE 1951.\" XXX 1952.\" .It Ic .JOIN 1953.\" XXX 1954.It Ic .MADE 1955Mark all sources of this target as being up-to-date. 1956.It Ic .MAKE 1957Execute the commands associated with this target even if the 1958.Fl n 1959or 1960.Fl t 1961options were specified. 1962Normally used to mark recursive 1963.Nm Ns s . 1964.It Ic .META 1965Create a meta file for the target, even if it is flagged as 1966.Ic .PHONY , 1967.Ic .MAKE , 1968or 1969.Ic .SPECIAL . 1970Usage in conjunction with 1971.Ic .MAKE 1972is the most likely case. 1973In "meta" mode, the target is out-of-date if the meta file is missing. 1974.It Ic .NOMETA 1975Do not create a meta file for the target. 1976Meta files are also not created for 1977.Ic .PHONY , 1978.Ic .MAKE , 1979or 1980.Ic .SPECIAL 1981targets. 1982.It Ic .NOMETA_CMP 1983Ignore differences in commands when deciding if target is out of date. 1984This is useful if the command contains a value which always changes. 1985If the number of commands change, though, the target will still be out of date. 1986The same effect applies to any command line that uses the variable 1987.Va .OODATE , 1988which can be used for that purpose even when not otherwise needed or desired: 1989.Bd -literal -offset indent 1990 1991skip-compare-for-some: 1992 @echo this will be compared 1993 @echo this will not ${.OODATE:M.NOMETA_CMP} 1994 @echo this will also be compared 1995 1996.Ed 1997The 1998.Cm \&:M 1999pattern suppresses any expansion of the unwanted variable. 2000.It Ic .NOPATH 2001Do not search for the target in the directories specified by 2002.Ic .PATH . 2003.It Ic .NOTMAIN 2004Normally 2005.Nm 2006selects the first target it encounters as the default target to be built 2007if no target was specified. 2008This source prevents this target from being selected. 2009.It Ic .OPTIONAL 2010If a target is marked with this attribute and 2011.Nm 2012can't figure out how to create it, it will ignore this fact and assume 2013the file isn't needed or already exists. 2014.It Ic .PHONY 2015The target does not 2016correspond to an actual file; it is always considered to be out of date, 2017and will not be created with the 2018.Fl t 2019option. 2020Suffix-transformation rules are not applied to 2021.Ic .PHONY 2022targets. 2023.It Ic .PRECIOUS 2024When 2025.Nm 2026is interrupted, it normally removes any partially made targets. 2027This source prevents the target from being removed. 2028.It Ic .RECURSIVE 2029Synonym for 2030.Ic .MAKE . 2031.It Ic .SILENT 2032Do not echo any of the commands associated with this target, exactly 2033as if they all were preceded by an at sign 2034.Pq Ql @ . 2035.It Ic .USE 2036Turn the target into 2037.Nm Ns 's 2038version of a macro. 2039When the target is used as a source for another target, the other target 2040acquires the commands, sources, and attributes (except for 2041.Ic .USE ) 2042of the 2043source. 2044If the target already has commands, the 2045.Ic .USE 2046target's commands are appended 2047to them. 2048.It Ic .USEBEFORE 2049Exactly like 2050.Ic .USE , 2051but prepend the 2052.Ic .USEBEFORE 2053target commands to the target. 2054.It Ic .WAIT 2055If 2056.Ic .WAIT 2057appears in a dependency line, the sources that precede it are 2058made before the sources that succeed it in the line. 2059Since the dependents of files are not made until the file itself 2060could be made, this also stops the dependents being built unless they 2061are needed for another branch of the dependency tree. 2062So given: 2063.Bd -literal 2064x: a .WAIT b 2065 echo x 2066a: 2067 echo a 2068b: b1 2069 echo b 2070b1: 2071 echo b1 2072 2073.Ed 2074the output is always 2075.Ql a , 2076.Ql b1 , 2077.Ql b , 2078.Ql x . 2079.br 2080The ordering imposed by 2081.Ic .WAIT 2082is only relevant for parallel makes. 2083.El 2084.Sh SPECIAL TARGETS 2085Special targets may not be included with other targets, i.e. they must be 2086the only target specified. 2087.Bl -tag -width .BEGINx 2088.It Ic .BEGIN 2089Any command lines attached to this target are executed before anything 2090else is done. 2091.It Ic .DEFAULT 2092This is sort of a 2093.Ic .USE 2094rule for any target (that was used only as a 2095source) that 2096.Nm 2097can't figure out any other way to create. 2098Only the shell script is used. 2099The 2100.Ic .IMPSRC 2101variable of a target that inherits 2102.Ic .DEFAULT Ns 's 2103commands is set 2104to the target's own name. 2105.It Ic .DELETE_ON_ERROR 2106If this target is present in the makefile, it globally causes make to 2107delete targets whose commands fail. 2108(By default, only targets whose commands are interrupted during 2109execution are deleted. 2110This is the historical behavior.) 2111This setting can be used to help prevent half-finished or malformed 2112targets from being left around and corrupting future rebuilds. 2113.It Ic .END 2114Any command lines attached to this target are executed after everything 2115else is done. 2116.It Ic .ERROR 2117Any command lines attached to this target are executed when another target fails. 2118The 2119.Ic .ERROR_TARGET 2120variable is set to the target that failed. 2121See also 2122.Ic MAKE_PRINT_VAR_ON_ERROR . 2123.It Ic .IGNORE 2124Mark each of the sources with the 2125.Ic .IGNORE 2126attribute. 2127If no sources are specified, this is the equivalent of specifying the 2128.Fl i 2129option. 2130.It Ic .INTERRUPT 2131If 2132.Nm 2133is interrupted, the commands for this target will be executed. 2134.It Ic .MAIN 2135If no target is specified when 2136.Nm 2137is invoked, this target will be built. 2138.It Ic .MAKEFLAGS 2139This target provides a way to specify flags for 2140.Nm 2141when the makefile is used. 2142The flags are as if typed to the shell, though the 2143.Fl f 2144option will have 2145no effect. 2146.\" XXX: NOT YET!!!! 2147.\" .It Ic .NOTPARALLEL 2148.\" The named targets are executed in non parallel mode. 2149.\" If no targets are 2150.\" specified, then all targets are executed in non parallel mode. 2151.It Ic .NOPATH 2152Apply the 2153.Ic .NOPATH 2154attribute to any specified sources. 2155.It Ic .NOTPARALLEL 2156Disable parallel mode. 2157.It Ic .NO_PARALLEL 2158Synonym for 2159.Ic .NOTPARALLEL , 2160for compatibility with other pmake variants. 2161.It Ic .OBJDIR 2162The source is a new value for 2163.Ql Va .OBJDIR . 2164If it exists, 2165.Nm 2166will 2167.Xr chdir 2 2168to it and update the value of 2169.Ql Va .OBJDIR . 2170.It Ic .ORDER 2171The named targets are made in sequence. 2172This ordering does not add targets to the list of targets to be made. 2173Since the dependents of a target do not get built until the target itself 2174could be built, unless 2175.Ql a 2176is built by another part of the dependency graph, 2177the following is a dependency loop: 2178.Bd -literal 2179\&.ORDER: b a 2180b: a 2181.Ed 2182.Pp 2183The ordering imposed by 2184.Ic .ORDER 2185is only relevant for parallel makes. 2186.\" XXX: NOT YET!!!! 2187.\" .It Ic .PARALLEL 2188.\" The named targets are executed in parallel mode. 2189.\" If no targets are 2190.\" specified, then all targets are executed in parallel mode. 2191.It Ic .PATH 2192The sources are directories which are to be searched for files not 2193found in the current directory. 2194If no sources are specified, any previously specified directories are 2195deleted. 2196If the source is the special 2197.Ic .DOTLAST 2198target, then the current working 2199directory is searched last. 2200.It Ic .PATH. Ns Va suffix 2201Like 2202.Ic .PATH 2203but applies only to files with a particular suffix. 2204The suffix must have been previously declared with 2205.Ic .SUFFIXES . 2206.It Ic .PHONY 2207Apply the 2208.Ic .PHONY 2209attribute to any specified sources. 2210.It Ic .PRECIOUS 2211Apply the 2212.Ic .PRECIOUS 2213attribute to any specified sources. 2214If no sources are specified, the 2215.Ic .PRECIOUS 2216attribute is applied to every 2217target in the file. 2218.It Ic .SHELL 2219Sets the shell that 2220.Nm 2221will use to execute commands. 2222The sources are a set of 2223.Ar field=value 2224pairs. 2225.Bl -tag -width hasErrCtls 2226.It Ar name 2227This is the minimal specification, used to select one of the built-in 2228shell specs; 2229.Ar sh , 2230.Ar ksh , 2231and 2232.Ar csh . 2233.It Ar path 2234Specifies the path to the shell. 2235.It Ar hasErrCtl 2236Indicates whether the shell supports exit on error. 2237.It Ar check 2238The command to turn on error checking. 2239.It Ar ignore 2240The command to disable error checking. 2241.It Ar echo 2242The command to turn on echoing of commands executed. 2243.It Ar quiet 2244The command to turn off echoing of commands executed. 2245.It Ar filter 2246The output to filter after issuing the 2247.Ar quiet 2248command. 2249It is typically identical to 2250.Ar quiet . 2251.It Ar errFlag 2252The flag to pass the shell to enable error checking. 2253.It Ar echoFlag 2254The flag to pass the shell to enable command echoing. 2255.It Ar newline 2256The string literal to pass the shell that results in a single newline 2257character when used outside of any quoting characters. 2258.El 2259Example: 2260.Bd -literal 2261\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e 2262 check="set \-e" ignore="set +e" \e 2263 echo="set \-v" quiet="set +v" filter="set +v" \e 2264 echoFlag=v errFlag=e newline="'\en'" 2265.Ed 2266.It Ic .SILENT 2267Apply the 2268.Ic .SILENT 2269attribute to any specified sources. 2270If no sources are specified, the 2271.Ic .SILENT 2272attribute is applied to every 2273command in the file. 2274.It Ic .STALE 2275This target gets run when a dependency file contains stale entries, having 2276.Va .ALLSRC 2277set to the name of that dependency file. 2278.It Ic .SUFFIXES 2279Each source specifies a suffix to 2280.Nm . 2281If no sources are specified, any previously specified suffixes are deleted. 2282It allows the creation of suffix-transformation rules. 2283.Pp 2284Example: 2285.Bd -literal 2286\&.SUFFIXES: .o 2287\&.c.o: 2288 cc \-o ${.TARGET} \-c ${.IMPSRC} 2289.Ed 2290.El 2291.Sh ENVIRONMENT 2292.Nm 2293uses the following environment variables, if they exist: 2294.Ev MACHINE , 2295.Ev MACHINE_ARCH , 2296.Ev MAKE , 2297.Ev MAKEFLAGS , 2298.Ev MAKEOBJDIR , 2299.Ev MAKEOBJDIRPREFIX , 2300.Ev MAKESYSPATH , 2301.Ev PWD , 2302and 2303.Ev TMPDIR . 2304.Pp 2305.Ev MAKEOBJDIRPREFIX 2306and 2307.Ev MAKEOBJDIR 2308may only be set in the environment or on the command line to 2309.Nm 2310and not as makefile variables; 2311see the description of 2312.Ql Va .OBJDIR 2313for more details. 2314.Sh FILES 2315.Bl -tag -width /usr/share/mk -compact 2316.It .depend 2317list of dependencies 2318.It Makefile 2319list of dependencies 2320.It makefile 2321list of dependencies 2322.It sys.mk 2323system makefile 2324.It /usr/share/mk 2325system makefile directory 2326.El 2327.Sh COMPATIBILITY 2328The basic make syntax is compatible between different versions of make; 2329however the special variables, variable modifiers and conditionals are not. 2330.Ss Older versions 2331An incomplete list of changes in older versions of 2332.Nm : 2333.Pp 2334The way that .for loop variables are substituted changed after 2335NetBSD 5.0 2336so that they still appear to be variable expansions. 2337In particular this stops them being treated as syntax, and removes some 2338obscure problems using them in .if statements. 2339.Pp 2340The way that parallel makes are scheduled changed in 2341NetBSD 4.0 2342so that .ORDER and .WAIT apply recursively to the dependent nodes. 2343The algorithms used may change again in the future. 2344.Ss Other make dialects 2345Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not 2346support most of the features of 2347.Nm 2348as described in this manual. 2349Most notably: 2350.Bl -bullet -offset indent 2351.It 2352The 2353.Ic .WAIT 2354and 2355.Ic .ORDER 2356declarations and most functionality pertaining to parallelization. 2357(GNU make supports parallelization but lacks these features needed to 2358control it effectively.) 2359.It 2360Directives, including for loops and conditionals and most of the 2361forms of include files. 2362(GNU make has its own incompatible and less powerful syntax for 2363conditionals.) 2364.It 2365All built-in variables that begin with a dot. 2366.It 2367Most of the special sources and targets that begin with a dot, 2368with the notable exception of 2369.Ic .PHONY , 2370.Ic .PRECIOUS , 2371and 2372.Ic .SUFFIXES . 2373.It 2374Variable modifiers, except for the 2375.Dl :old=new 2376string substitution, which does not portably support globbing with 2377.Ql % 2378and historically only works on declared suffixes. 2379.It 2380The 2381.Ic $> 2382variable even in its short form; most makes support this functionality 2383but its name varies. 2384.El 2385.Pp 2386Some features are somewhat more portable, such as assignment with 2387.Ic += , 2388.Ic ?= , 2389and 2390.Ic != . 2391The 2392.Ic .PATH 2393functionality is based on an older feature 2394.Ic VPATH 2395found in GNU make and many versions of SVR4 make; however, 2396historically its behavior is too ill-defined (and too buggy) to rely 2397upon. 2398.Pp 2399The 2400.Ic $@ 2401and 2402.Ic $< 2403variables are more or less universally portable, as is the 2404.Ic $(MAKE) 2405variable. 2406Basic use of suffix rules (for files only in the current directory, 2407not trying to chain transformations together, etc.) is also reasonably 2408portable. 2409.Sh SEE ALSO 2410.Xr mkdep 1 2411.Sh HISTORY 2412.Nm 2413is derived from NetBSD 2414.Xr make 1 . 2415It uses autoconf to facilitate portability to other platforms. 2416.Pp 2417A 2418make 2419command appeared in 2420.At v7 . 2421This 2422make 2423implementation is based on Adam De Boor's pmake program which was written 2424for Sprite at Berkeley. 2425It was designed to be a parallel distributed make running jobs on different 2426machines using a daemon called 2427.Dq customs . 2428.Pp 2429Historically the target/dependency 2430.Dq FRC 2431has been used to FoRCe rebuilding (since the target/dependency 2432does not exist... unless someone creates an 2433.Dq FRC 2434file). 2435.Sh BUGS 2436The 2437make 2438syntax is difficult to parse without actually acting on the data. 2439For instance, finding the end of a variable's use should involve scanning 2440each of the modifiers, using the correct terminator for each field. 2441In many places 2442make 2443just counts {} and () in order to find the end of a variable expansion. 2444.Pp 2445There is no way of escaping a space character in a filename. 2446