1.\" $NetBSD: make.1,v 1.289 2020/08/28 17:15:04 rillig 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 August 28, 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 h 170Print debugging information about hash table operations. 171.It Ar j 172Print debugging information about running multiple shells. 173.It Ar L 174Turn on lint checks. 175This will throw errors for variable assignments that do not parse 176correctly, at the time of assignment so the file and line number 177are available. 178.It Ar l 179Print commands in Makefiles regardless of whether or not they are prefixed by 180.Ql @ 181or other "quiet" flags. 182Also known as "loud" behavior. 183.It Ar M 184Print debugging information about "meta" mode decisions about targets. 185.It Ar m 186Print debugging information about making targets, including modification 187dates. 188.It Ar n 189Don't delete the temporary command scripts created when running commands. 190These temporary scripts are created in the directory 191referred to by the 192.Ev TMPDIR 193environment variable, or in 194.Pa /tmp 195if 196.Ev TMPDIR 197is unset or set to the empty string. 198The temporary scripts are created by 199.Xr mkstemp 3 , 200and have names of the form 201.Pa makeXXXXXX . 202.Em NOTE : 203This can create many files in 204.Ev TMPDIR 205or 206.Pa /tmp , 207so use with care. 208.It Ar p 209Print debugging information about makefile parsing. 210.It Ar s 211Print debugging information about suffix-transformation rules. 212.It Ar t 213Print debugging information about target list maintenance. 214.It Ar V 215Force the 216.Fl V 217option to print raw values of variables, overriding the default behavior 218set via 219.Va .MAKE.EXPAND_VARIABLES . 220.It Ar v 221Print debugging information about variable assignment. 222.It Ar x 223Run shell commands with 224.Fl x 225so the actual commands are printed as they are executed. 226.El 227.It Fl e 228Specify that environment variables override macro assignments within 229makefiles. 230.It Fl f Ar makefile 231Specify a makefile to read instead of the default 232.Ql Pa makefile . 233If 234.Ar makefile 235is 236.Ql Fl , 237standard input is read. 238Multiple makefiles may be specified, and are read in the order specified. 239.It Fl I Ar directory 240Specify a directory in which to search for makefiles and included makefiles. 241The system makefile directory (or directories, see the 242.Fl m 243option) is automatically included as part of this list. 244.It Fl i 245Ignore non-zero exit of shell commands in the makefile. 246Equivalent to specifying 247.Ql Fl 248before each command line in the makefile. 249.It Fl J Ar private 250This option should 251.Em not 252be specified by the user. 253.Pp 254When the 255.Ar j 256option is in use in a recursive build, this option is passed by a make 257to child makes to allow all the make processes in the build to 258cooperate to avoid overloading the system. 259.It Fl j Ar max_jobs 260Specify the maximum number of jobs that 261.Nm 262may have running at any one time. 263The value is saved in 264.Va .MAKE.JOBS . 265Turns compatibility mode off, unless the 266.Ar B 267flag is also specified. 268When compatibility mode is off, all commands associated with a 269target are executed in a single shell invocation as opposed to the 270traditional one shell invocation per line. 271This can break traditional scripts which change directories on each 272command invocation and then expect to start with a fresh environment 273on the next line. 274It is more efficient to correct the scripts rather than turn backwards 275compatibility on. 276.It Fl k 277Continue processing after errors are encountered, but only on those targets 278that do not depend on the target whose creation caused the error. 279.It Fl m Ar directory 280Specify a directory in which to search for sys.mk and makefiles included 281via the 282.Li \&< Ns Ar file Ns Li \&> Ns -style 283include statement. 284The 285.Fl m 286option can be used multiple times to form a search path. 287This path will override the default system include path: /usr/share/mk. 288Furthermore the system include path will be appended to the search path used 289for 290.Li \*q Ns Ar file Ns Li \*q Ns -style 291include statements (see the 292.Fl I 293option). 294.Pp 295If a file or directory name in the 296.Fl m 297argument (or the 298.Ev MAKESYSPATH 299environment variable) starts with the string 300.Qq \&.../ 301then 302.Nm 303will search for the specified file or directory named in the remaining part 304of the argument string. 305The search starts with the current directory of 306the Makefile and then works upward towards the root of the file system. 307If the search is successful, then the resulting directory replaces the 308.Qq \&.../ 309specification in the 310.Fl m 311argument. 312If used, this feature allows 313.Nm 314to easily search in the current source tree for customized sys.mk files 315(e.g., by using 316.Qq \&.../mk/sys.mk 317as an argument). 318.It Fl n 319Display the commands that would have been executed, but do not 320actually execute them unless the target depends on the .MAKE special 321source (see below) or the command is prefixed with 322.Ql Ic + . 323.It Fl N 324Display the commands which would have been executed, but do not 325actually execute any of them; useful for debugging top-level makefiles 326without descending into subdirectories. 327.It Fl q 328Do not execute any commands, but exit 0 if the specified targets are 329up-to-date and 1, otherwise. 330.It Fl r 331Do not use the built-in rules specified in the system makefile. 332.It Fl s 333Do not echo any commands as they are executed. 334Equivalent to specifying 335.Ql Ic @ 336before each command line in the makefile. 337.It Fl T Ar tracefile 338When used with the 339.Fl j 340flag, 341append a trace record to 342.Ar tracefile 343for each job started and completed. 344.It Fl t 345Rather than re-building a target as specified in the makefile, create it 346or update its modification time to make it appear up-to-date. 347.It Fl V Ar variable 348Print the value of 349.Ar variable . 350Do not build any targets. 351Multiple instances of this option may be specified; 352the variables will be printed one per line, 353with a blank line for each null or undefined variable. 354The value printed is extracted from the global context after all 355makefiles have been read. 356By default, the raw variable contents (which may 357include additional unexpanded variable references) are shown. 358If 359.Ar variable 360contains a 361.Ql \&$ 362then the value will be recursively expanded to its complete resultant 363text before printing. 364The expanded value will also be printed if 365.Va .MAKE.EXPAND_VARIABLES 366is set to true and 367the 368.Fl dV 369option has not been used to override it. 370Note that loop-local and target-local variables, as well as values 371taken temporarily by global variables during makefile processing, are 372not accessible via this option. 373The 374.Fl dv 375debug mode can be used to see these at the cost of generating 376substantial extraneous output. 377.It Fl v Ar variable 378Like 379.Fl V 380but the variable is always expanded to its complete value. 381.It Fl W 382Treat any warnings during makefile parsing as errors. 383.It Fl w 384Print entering and leaving directory messages, pre and post processing. 385.It Fl X 386Don't export variables passed on the command line to the environment 387individually. 388Variables passed on the command line are still exported 389via the 390.Va MAKEFLAGS 391environment variable. 392This option may be useful on systems which have a small limit on the 393size of command arguments. 394.It Ar variable=value 395Set the value of the variable 396.Ar variable 397to 398.Ar value . 399Normally, all values passed on the command line are also exported to 400sub-makes in the environment. 401The 402.Fl X 403flag disables this behavior. 404Variable assignments should follow options for POSIX compatibility 405but no ordering is enforced. 406.El 407.Pp 408There are seven different types of lines in a makefile: file dependency 409specifications, shell commands, variable assignments, include statements, 410conditional directives, for loops, and comments. 411.Pp 412In general, lines may be continued from one line to the next by ending 413them with a backslash 414.Pq Ql \e . 415The trailing newline character and initial whitespace on the following 416line are compressed into a single space. 417.Sh FILE DEPENDENCY SPECIFICATIONS 418Dependency lines consist of one or more targets, an operator, and zero 419or more sources. 420This creates a relationship where the targets 421.Dq depend 422on the sources 423and are customarily created from them. 424A target is considered out-of-date if it does not exist, or if its 425modification time is less than that of any of its sources. 426An out-of-date target will be re-created, but not until all sources 427have been examined and themselves re-created as needed. 428Three operators may be used: 429.Bl -tag -width flag 430.It Ic \&: 431Many dependency lines may name this target but only one may have 432attached shell commands. 433All sources named in all dependency lines are considered together, 434and if needed the attached shell commands are run to create or 435re-create the target. 436If 437.Nm 438is interrupted, the target is removed. 439.It Ic \&! 440The same, but the target is always re-created whether or not it is out 441of date. 442.It Ic \&:: 443Any dependency line may have attached shell commands, but each one 444is handled independently: its sources are considered and the attached 445shell commands are run if the target is out of date with respect to 446(only) those sources. 447Thus, different groups of the attached shell commands may be run 448depending on the circumstances. 449Furthermore, unlike 450.Ic \&:, 451for dependency lines with no sources, the attached shell 452commands are always run. 453Also unlike 454.Ic \&:, 455the target will not be removed if 456.Nm 457is interrupted. 458.El 459All dependency lines mentioning a particular target must use the same 460operator. 461.Pp 462Targets and sources may contain the shell wildcard values 463.Ql \&? , 464.Ql * , 465.Ql [] , 466and 467.Ql {} . 468The values 469.Ql \&? , 470.Ql * , 471and 472.Ql [] 473may only be used as part of the final 474component of the target or source, and must be used to describe existing 475files. 476The value 477.Ql {} 478need not necessarily be used to describe existing files. 479Expansion is in directory order, not alphabetically as done in the shell. 480.Sh SHELL COMMANDS 481Each target may have associated with it one or more lines of shell 482commands, normally 483used to create the target. 484Each of the lines in this script 485.Em must 486be preceded by a tab. 487(For historical reasons, spaces are not accepted.) 488While targets can appear in many dependency lines if desired, by 489default only one of these rules may be followed by a creation 490script. 491If the 492.Ql Ic \&:: 493operator is used, however, all rules may include scripts and the 494scripts are executed in the order found. 495.Pp 496Each line is treated as a separate shell command, unless the end of 497line is escaped with a backslash 498.Pq Ql \e 499in which case that line and the next are combined. 500.\" The escaped newline is retained and passed to the shell, which 501.\" normally ignores it. 502.\" However, the tab at the beginning of the following line is removed. 503If the first characters of the command are any combination of 504.Ql Ic @ , 505.Ql Ic + , 506or 507.Ql Ic \- , 508the command is treated specially. 509A 510.Ql Ic @ 511causes the command not to be echoed before it is executed. 512A 513.Ql Ic + 514causes the command to be executed even when 515.Fl n 516is given. 517This is similar to the effect of the .MAKE special source, 518except that the effect can be limited to a single line of a script. 519A 520.Ql Ic \- 521in compatibility mode 522causes any non-zero exit status of the command line to be ignored. 523.Pp 524When 525.Nm 526is run in jobs mode with 527.Fl j Ar max_jobs , 528the entire script for the target is fed to a 529single instance of the shell. 530In compatibility (non-jobs) mode, each command is run in a separate process. 531If the command contains any shell meta characters 532.Pq Ql #=|^(){};&<>*?[]:$`\e\en 533it will be passed to the shell; otherwise 534.Nm 535will attempt direct execution. 536If a line starts with 537.Ql Ic \- 538and the shell has ErrCtl enabled then failure of the command line 539will be ignored as in compatibility mode. 540Otherwise 541.Ql Ic \- 542affects the entire job; 543the script will stop at the first command line that fails, 544but the target will not be deemed to have failed. 545.Pp 546Makefiles should be written so that the mode of 547.Nm 548operation does not change their behavior. 549For example, any command which needs to use 550.Dq cd 551or 552.Dq chdir 553without potentially changing the directory for subsequent commands 554should be put in parentheses so it executes in a subshell. 555To force the use of one shell, escape the line breaks so as to make 556the whole script one command. 557For example: 558.Bd -literal -offset indent 559avoid-chdir-side-effects: 560 @echo Building $@ in `pwd` 561 @(cd ${.CURDIR} && ${MAKE} $@) 562 @echo Back in `pwd` 563 564ensure-one-shell-regardless-of-mode: 565 @echo Building $@ in `pwd`; \e 566 (cd ${.CURDIR} && ${MAKE} $@); \e 567 echo Back in `pwd` 568.Ed 569.Pp 570Since 571.Nm 572will 573.Xr chdir 2 574to 575.Ql Va .OBJDIR 576before executing any targets, each child process 577starts with that as its current working directory. 578.Sh VARIABLE ASSIGNMENTS 579Variables in make are much like variables in the shell, and, by tradition, 580consist of all upper-case letters. 581.Ss Variable assignment modifiers 582The five operators that can be used to assign values to variables are as 583follows: 584.Bl -tag -width Ds 585.It Ic \&= 586Assign the value to the variable. 587Any previous value is overridden. 588.It Ic \&+= 589Append the value to the current value of the variable. 590.It Ic \&?= 591Assign the value to the variable if it is not already defined. 592.It Ic \&:= 593Assign with expansion, i.e. expand the value before assigning it 594to the variable. 595Normally, expansion is not done until the variable is referenced. 596.Em NOTE : 597References to undefined variables are 598.Em not 599expanded. 600This can cause problems when variable modifiers are used. 601.It Ic \&!= 602Expand the value and pass it to the shell for execution and assign 603the result to the variable. 604Any newlines in the result are replaced with spaces. 605.El 606.Pp 607Any white-space before the assigned 608.Ar value 609is removed; if the value is being appended, a single space is inserted 610between the previous contents of the variable and the appended value. 611.Pp 612Variables are expanded by surrounding the variable name with either 613curly braces 614.Pq Ql {} 615or parentheses 616.Pq Ql () 617and preceding it with 618a dollar sign 619.Pq Ql \&$ . 620If the variable name contains only a single letter, the surrounding 621braces or parentheses are not required. 622This shorter form is not recommended. 623.Pp 624If the variable name contains a dollar, then the name itself is expanded first. 625This allows almost arbitrary variable names, however names containing dollar, 626braces, parentheses, or whitespace are really best avoided! 627.Pp 628If the result of expanding a variable contains a dollar sign 629.Pq Ql \&$ 630the string is expanded again. 631.Pp 632Variable substitution occurs at three distinct times, depending on where 633the variable is being used. 634.Bl -enum 635.It 636Variables in dependency lines are expanded as the line is read. 637.It 638Variables in shell commands are expanded when the shell command is 639executed. 640.It 641.Dq .for 642loop index variables are expanded on each loop iteration. 643Note that other variables are not expanded inside loops so 644the following example code: 645.Bd -literal -offset indent 646 647.Dv .for i in 1 2 3 648a+= ${i} 649j= ${i} 650b+= ${j} 651.Dv .endfor 652 653all: 654 @echo ${a} 655 @echo ${b} 656 657.Ed 658will print: 659.Bd -literal -offset indent 6601 2 3 6613 3 3 662 663.Ed 664Because while ${a} contains 665.Dq 1 2 3 666after the loop is executed, ${b} 667contains 668.Dq ${j} ${j} ${j} 669which expands to 670.Dq 3 3 3 671since after the loop completes ${j} contains 672.Dq 3 . 673.El 674.Ss Variable classes 675The four different classes of variables (in order of increasing precedence) 676are: 677.Bl -tag -width Ds 678.It Environment variables 679Variables defined as part of 680.Nm Ns 's 681environment. 682.It Global variables 683Variables defined in the makefile or in included makefiles. 684.It Command line variables 685Variables defined as part of the command line. 686.It Local variables 687Variables that are defined specific to a certain target. 688.El 689.Pp 690Local variables are all built in and their values vary magically from 691target to target. 692It is not currently possible to define new local variables. 693The seven local variables are as follows: 694.Bl -tag -width ".ARCHIVE" -offset indent 695.It Va .ALLSRC 696The list of all sources for this target; also known as 697.Ql Va \&> . 698.It Va .ARCHIVE 699The name of the archive file; also known as 700.Ql Va \&! . 701.It Va .IMPSRC 702In suffix-transformation rules, the name/path of the source from which the 703target is to be transformed (the 704.Dq implied 705source); also known as 706.Ql Va \&< . 707It is not defined in explicit rules. 708.It Va .MEMBER 709The name of the archive member; also known as 710.Ql Va % . 711.It Va .OODATE 712The list of sources for this target that were deemed out-of-date; also 713known as 714.Ql Va \&? . 715.It Va .PREFIX 716The file prefix of the target, containing only the file portion, no suffix 717or preceding directory components; also known as 718.Ql Va * . 719The suffix must be one of the known suffixes declared with 720.Ic .SUFFIXES 721or it will not be recognized. 722.It Va .TARGET 723The name of the target; also known as 724.Ql Va @ . 725For compatibility with other makes this is an alias for 726.Ic .ARCHIVE 727in archive member rules. 728.El 729.Pp 730The shorter forms 731.Ql ( Va > , 732.Ql Va \&! , 733.Ql Va < , 734.Ql Va % , 735.Ql Va \&? , 736.Ql Va * , 737and 738.Ql Va @ ) 739are permitted for backward 740compatibility with historical makefiles and legacy POSIX make and are 741not recommended. 742.Pp 743Variants of these variables with the punctuation followed immediately by 744.Ql D 745or 746.Ql F , 747e.g. 748.Ql Va $(@D) , 749are legacy forms equivalent to using the 750.Ql :H 751and 752.Ql :T 753modifiers. 754These forms are accepted for compatibility with 755.At V 756makefiles and POSIX but are not recommended. 757.Pp 758Four of the local variables may be used in sources on dependency lines 759because they expand to the proper value for each target on the line. 760These variables are 761.Ql Va .TARGET , 762.Ql Va .PREFIX , 763.Ql Va .ARCHIVE , 764and 765.Ql Va .MEMBER . 766.Ss Additional built-in variables 767In addition, 768.Nm 769sets or knows about the following variables: 770.Bl -tag -width .MAKEOVERRIDES 771.It Va \&$ 772A single dollar sign 773.Ql \&$ , 774i.e. 775.Ql \&$$ 776expands to a single dollar 777sign. 778.It Va .ALLTARGETS 779The list of all targets encountered in the Makefile. 780If evaluated during 781Makefile parsing, lists only those targets encountered thus far. 782.It Va .CURDIR 783A path to the directory where 784.Nm 785was executed. 786Refer to the description of 787.Ql Ev PWD 788for more details. 789.It Va .INCLUDEDFROMDIR 790The directory of the file this Makefile was included from. 791.It Va .INCLUDEDFROMFILE 792The filename of the file this Makefile was included from. 793.It Ev MAKE 794The name that 795.Nm 796was executed with 797.Pq Va argv[0] . 798For compatibility 799.Nm 800also sets 801.Va .MAKE 802with the same value. 803The preferred variable to use is the environment variable 804.Ev MAKE 805because it is more compatible with other versions of 806.Nm 807and cannot be confused with the special target with the same name. 808.It Va .MAKE.ALWAYS_PASS_JOB_QUEUE 809Tells 810.Nm 811whether to pass the descriptors of the job token queue 812even if the target is not tagged with 813.Ic .MAKE 814The default is 815.Ql Pa yes 816for backwards compatability with 817.Fx 9.0 818and earlier. 819.It Va .MAKE.DEPENDFILE 820Names the makefile (default 821.Ql Pa .depend ) 822from which generated dependencies are read. 823.It Va .MAKE.EXPAND_VARIABLES 824A boolean that controls the default behavior of the 825.Fl V 826option. 827If true, variable values printed with 828.Fl V 829are fully expanded; if false, the raw variable contents (which may 830include additional unexpanded variable references) are shown. 831.It Va .MAKE.EXPORTED 832The list of variables exported by 833.Nm . 834.It Va .MAKE.JOBS 835The argument to the 836.Fl j 837option. 838.It Va .MAKE.JOB.PREFIX 839If 840.Nm 841is run with 842.Ar j 843then output for each target is prefixed with a token 844.Ql --- target --- 845the first part of which can be controlled via 846.Va .MAKE.JOB.PREFIX . 847If 848.Va .MAKE.JOB.PREFIX 849is empty, no token is printed. 850.br 851For example: 852.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}] 853would produce tokens like 854.Ql ---make[1234] target --- 855making it easier to track the degree of parallelism being achieved. 856.It Ev MAKEFLAGS 857The environment variable 858.Ql Ev MAKEFLAGS 859may contain anything that 860may be specified on 861.Nm Ns 's 862command line. 863Anything specified on 864.Nm Ns 's 865command line is appended to the 866.Ql Ev MAKEFLAGS 867variable which is then 868entered into the environment for all programs which 869.Nm 870executes. 871.It Va .MAKE.LEVEL 872The recursion depth of 873.Nm . 874The initial instance of 875.Nm 876will be 0, and an incremented value is put into the environment 877to be seen by the next generation. 878This allows tests like: 879.Li .if ${.MAKE.LEVEL} == 0 880to protect things which should only be evaluated in the initial instance of 881.Nm . 882.It Va .MAKE.MAKEFILE_PREFERENCE 883The ordered list of makefile names 884(default 885.Ql Pa makefile , 886.Ql Pa Makefile ) 887that 888.Nm 889will look for. 890.It Va .MAKE.MAKEFILES 891The list of makefiles read by 892.Nm , 893which is useful for tracking dependencies. 894Each makefile is recorded only once, regardless of the number of times read. 895.It Va .MAKE.MODE 896Processed after reading all makefiles. 897Can affect the mode that 898.Nm 899runs in. 900It can contain a number of keywords: 901.Bl -hang -width missing-filemon=bf. 902.It Pa compat 903Like 904.Fl B , 905puts 906.Nm 907into "compat" mode. 908.It Pa meta 909Puts 910.Nm 911into "meta" mode, where meta files are created for each target 912to capture the command run, the output generated and if 913.Xr filemon 4 914is available, the system calls which are of interest to 915.Nm . 916The captured output can be very useful when diagnosing errors. 917.It Pa curdirOk= Ar bf 918Normally 919.Nm 920will not create .meta files in 921.Ql Va .CURDIR . 922This can be overridden by setting 923.Va bf 924to a value which represents True. 925.It Pa missing-meta= Ar bf 926If 927.Va bf 928is True, then a missing .meta file makes the target out-of-date. 929.It Pa missing-filemon= Ar bf 930If 931.Va bf 932is True, then missing filemon data makes the target out-of-date. 933.It Pa nofilemon 934Do not use 935.Xr filemon 4 . 936.It Pa env 937For debugging, it can be useful to include the environment 938in the .meta file. 939.It Pa verbose 940If in "meta" mode, print a clue about the target being built. 941This is useful if the build is otherwise running silently. 942The message printed the value of: 943.Va .MAKE.META.PREFIX . 944.It Pa ignore-cmd 945Some makefiles have commands which are simply not stable. 946This keyword causes them to be ignored for 947determining whether a target is out of date in "meta" mode. 948See also 949.Ic .NOMETA_CMP . 950.It Pa silent= Ar bf 951If 952.Va bf 953is True, when a .meta file is created, mark the target 954.Ic .SILENT . 955.El 956.It Va .MAKE.META.BAILIWICK 957In "meta" mode, provides a list of prefixes which 958match the directories controlled by 959.Nm . 960If a file that was generated outside of 961.Va .OBJDIR 962but within said bailiwick is missing, 963the current target is considered out-of-date. 964.It Va .MAKE.META.CREATED 965In "meta" mode, this variable contains a list of all the meta files 966updated. 967If not empty, it can be used to trigger processing of 968.Va .MAKE.META.FILES . 969.It Va .MAKE.META.FILES 970In "meta" mode, this variable contains a list of all the meta files 971used (updated or not). 972This list can be used to process the meta files to extract dependency 973information. 974.It Va .MAKE.META.IGNORE_PATHS 975Provides a list of path prefixes that should be ignored; 976because the contents are expected to change over time. 977The default list includes: 978.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp 979.It Va .MAKE.META.IGNORE_PATTERNS 980Provides a list of patterns to match against pathnames. 981Ignore any that match. 982.It Va .MAKE.META.IGNORE_FILTER 983Provides a list of variable modifiers to apply to each pathname. 984Ignore if the expansion is an empty string. 985.It Va .MAKE.META.PREFIX 986Defines the message printed for each meta file updated in "meta verbose" mode. 987The default value is: 988.Dl Building ${.TARGET:H:tA}/${.TARGET:T} 989.It Va .MAKEOVERRIDES 990This variable is used to record the names of variables assigned to 991on the command line, so that they may be exported as part of 992.Ql Ev MAKEFLAGS . 993This behavior can be disabled by assigning an empty value to 994.Ql Va .MAKEOVERRIDES 995within a makefile. 996Extra variables can be exported from a makefile 997by appending their names to 998.Ql Va .MAKEOVERRIDES . 999.Ql Ev MAKEFLAGS 1000is re-exported whenever 1001.Ql Va .MAKEOVERRIDES 1002is modified. 1003.It Va .MAKE.PATH_FILEMON 1004If 1005.Nm 1006was built with 1007.Xr filemon 4 1008support, this is set to the path of the device node. 1009This allows makefiles to test for this support. 1010.It Va .MAKE.PID 1011The process-id of 1012.Nm . 1013.It Va .MAKE.PPID 1014The parent process-id of 1015.Nm . 1016.It Va .MAKE.SAVE_DOLLARS 1017value should be a boolean that controls whether 1018.Ql $$ 1019are preserved when doing 1020.Ql := 1021assignments. 1022The default is false, for backwards compatibility. 1023Set to true for compatability with other makes. 1024If set to false, 1025.Ql $$ 1026becomes 1027.Ql $ 1028per normal evaluation rules. 1029.It Va MAKE_PRINT_VAR_ON_ERROR 1030When 1031.Nm 1032stops due to an error, it sets 1033.Ql Va .ERROR_TARGET 1034to the name of the target that failed, 1035.Ql Va .ERROR_CMD 1036to the commands of the failed target, 1037and in "meta" mode, it also sets 1038.Ql Va .ERROR_CWD 1039to the 1040.Xr getcwd 3 , 1041and 1042.Ql Va .ERROR_META_FILE 1043to the path of the meta file (if any) describing the failed target. 1044It then prints its name and the value of 1045.Ql Va .CURDIR 1046as well as the value of any variables named in 1047.Ql Va MAKE_PRINT_VAR_ON_ERROR . 1048.It Va .newline 1049This variable is simply assigned a newline character as its value. 1050This allows expansions using the 1051.Cm \&:@ 1052modifier to put a newline between 1053iterations of the loop rather than a space. 1054For example, the printing of 1055.Ql Va MAKE_PRINT_VAR_ON_ERROR 1056could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}. 1057.It Va .OBJDIR 1058A path to the directory where the targets are built. 1059Its value is determined by trying to 1060.Xr chdir 2 1061to the following directories in order and using the first match: 1062.Bl -enum 1063.It 1064.Ev ${MAKEOBJDIRPREFIX}${.CURDIR} 1065.Pp 1066(Only if 1067.Ql Ev MAKEOBJDIRPREFIX 1068is set in the environment or on the command line.) 1069.It 1070.Ev ${MAKEOBJDIR} 1071.Pp 1072(Only if 1073.Ql Ev MAKEOBJDIR 1074is set in the environment or on the command line.) 1075.It 1076.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE} 1077.It 1078.Ev ${.CURDIR} Ns Pa /obj 1079.It 1080.Pa /usr/obj/ Ns Ev ${.CURDIR} 1081.It 1082.Ev ${.CURDIR} 1083.El 1084.Pp 1085Variable expansion is performed on the value before it's used, 1086so expressions such as 1087.Dl ${.CURDIR:S,^/usr/src,/var/obj,} 1088may be used. 1089This is especially useful with 1090.Ql Ev MAKEOBJDIR . 1091.Pp 1092.Ql Va .OBJDIR 1093may be modified in the makefile via the special target 1094.Ql Ic .OBJDIR . 1095In all cases, 1096.Nm 1097will 1098.Xr chdir 2 1099to the specified directory if it exists, and set 1100.Ql Va .OBJDIR 1101and 1102.Ql Ev PWD 1103to that directory before executing any targets. 1104. 1105.It Va .PARSEDIR 1106A path to the directory of the current 1107.Ql Pa Makefile 1108being parsed. 1109.It Va .PARSEFILE 1110The basename of the current 1111.Ql Pa Makefile 1112being parsed. 1113This variable and 1114.Ql Va .PARSEDIR 1115are both set only while the 1116.Ql Pa Makefiles 1117are being parsed. 1118If you want to retain their current values, assign them to a variable 1119using assignment with expansion: 1120.Pq Ql Cm \&:= . 1121.It Va .PATH 1122A variable that represents the list of directories that 1123.Nm 1124will search for files. 1125The search list should be updated using the target 1126.Ql Va .PATH 1127rather than the variable. 1128.It Ev PWD 1129Alternate path to the current directory. 1130.Nm 1131normally sets 1132.Ql Va .CURDIR 1133to the canonical path given by 1134.Xr getcwd 3 . 1135However, if the environment variable 1136.Ql Ev PWD 1137is set and gives a path to the current directory, then 1138.Nm 1139sets 1140.Ql Va .CURDIR 1141to the value of 1142.Ql Ev PWD 1143instead. 1144This behavior is disabled if 1145.Ql Ev MAKEOBJDIRPREFIX 1146is set or 1147.Ql Ev MAKEOBJDIR 1148contains a variable transform. 1149.Ql Ev PWD 1150is set to the value of 1151.Ql Va .OBJDIR 1152for all programs which 1153.Nm 1154executes. 1155.It Ev .SHELL 1156The pathname of the shell used to run target scripts. 1157It is read-only. 1158.It Ev .TARGETS 1159The list of targets explicitly specified on the command line, if any. 1160.It Ev VPATH 1161Colon-separated 1162.Pq Dq \&: 1163lists of directories that 1164.Nm 1165will search for files. 1166The variable is supported for compatibility with old make programs only, 1167use 1168.Ql Va .PATH 1169instead. 1170.El 1171.Ss Variable modifiers 1172Variable expansion may be modified to select or modify each word of the 1173variable (where a 1174.Dq word 1175is white-space delimited sequence of characters). 1176The general format of a variable expansion is as follows: 1177.Pp 1178.Dl ${variable[:modifier[:...]]} 1179.Pp 1180Each modifier begins with a colon, 1181which may be escaped with a backslash 1182.Pq Ql \e . 1183.Pp 1184A set of modifiers can be specified via a variable, as follows: 1185.Pp 1186.Dl modifier_variable=modifier[:...] 1187.Dl ${variable:${modifier_variable}[:...]} 1188.Pp 1189In this case the first modifier in the modifier_variable does not 1190start with a colon, since that must appear in the referencing 1191variable. 1192If any of the modifiers in the modifier_variable contain a dollar sign 1193.Pq Ql $ , 1194these must be doubled to avoid early expansion. 1195.Pp 1196The supported modifiers are: 1197.Bl -tag -width EEE 1198.It Cm \&:E 1199Replaces each word in the variable with its suffix. 1200.It Cm \&:H 1201Replaces each word in the variable with everything but the last component. 1202.It Cm \&:M Ns Ar pattern 1203Selects only those words that match 1204.Ar pattern . 1205The standard shell wildcard characters 1206.Pf ( Ql * , 1207.Ql \&? , 1208and 1209.Ql Oo Oc ) 1210may 1211be used. 1212The wildcard characters may be escaped with a backslash 1213.Pq Ql \e . 1214As a consequence of the way values are split into words, matched, 1215and then joined, a construct like 1216.Dl ${VAR:M*} 1217will normalize the inter-word spacing, removing all leading and 1218trailing space, and converting multiple consecutive spaces 1219to single spaces. 1220. 1221.It Cm \&:N Ns Ar pattern 1222This is identical to 1223.Ql Cm \&:M , 1224but selects all words which do not match 1225.Ar pattern . 1226.It Cm \&:O 1227Orders every word in variable alphabetically. 1228.It Cm \&:Or 1229Orders every word in variable in reverse alphabetical order. 1230.It Cm \&:Ox 1231Shuffles the words in variable. 1232The results will be different each time you are referring to the 1233modified variable; use the assignment with expansion 1234.Pq Ql Cm \&:= 1235to prevent such behavior. 1236For example, 1237.Bd -literal -offset indent 1238LIST= uno due tre quattro 1239RANDOM_LIST= ${LIST:Ox} 1240STATIC_RANDOM_LIST:= ${LIST:Ox} 1241 1242all: 1243 @echo "${RANDOM_LIST}" 1244 @echo "${RANDOM_LIST}" 1245 @echo "${STATIC_RANDOM_LIST}" 1246 @echo "${STATIC_RANDOM_LIST}" 1247.Ed 1248may produce output similar to: 1249.Bd -literal -offset indent 1250quattro due tre uno 1251tre due quattro uno 1252due uno quattro tre 1253due uno quattro tre 1254.Ed 1255.It Cm \&:Q 1256Quotes every shell meta-character in the variable, so that it can be passed 1257safely to the shell. 1258.It Cm \&:q 1259Quotes every shell meta-character in the variable, and also doubles 1260.Sq $ 1261characters so that it can be passed 1262safely through recursive invocations of 1263.Nm . 1264This is equivalent to: 1265.Sq \&:S/\e\&$/&&/g:Q . 1266.It Cm \&:R 1267Replaces each word in the variable with everything but its suffix. 1268.It Cm \&:range[=count] 1269The value is an integer sequence representing the words of the original 1270value, or the supplied 1271.Va count . 1272.It Cm \&:gmtime[=utc] 1273The value is a format string for 1274.Xr strftime 3 , 1275using 1276.Xr gmtime 3 . 1277If a 1278.Va utc 1279value is not provided or is 0, the current time is used. 1280.It Cm \&:hash 1281Computes a 32-bit hash of the value and encode it as hex digits. 1282.It Cm \&:localtime[=utc] 1283The value is a format string for 1284.Xr strftime 3 , 1285using 1286.Xr localtime 3 . 1287If a 1288.Va utc 1289value is not provided or is 0, the current time is used. 1290.It Cm \&:tA 1291Attempts to convert variable to an absolute path using 1292.Xr realpath 3 , 1293if that fails, the value is unchanged. 1294.It Cm \&:tl 1295Converts variable to lower-case letters. 1296.It Cm \&:ts Ns Ar c 1297Words in the variable are normally separated by a space on expansion. 1298This modifier sets the separator to the character 1299.Ar c . 1300If 1301.Ar c 1302is omitted, then no separator is used. 1303The common escapes (including octal numeric codes) work as expected. 1304.It Cm \&:tu 1305Converts variable to upper-case letters. 1306.It Cm \&:tW 1307Causes the value to be treated as a single word 1308(possibly containing embedded white space). 1309See also 1310.Ql Cm \&:[*] . 1311.It Cm \&:tw 1312Causes the value to be treated as a sequence of 1313words delimited by white space. 1314See also 1315.Ql Cm \&:[@] . 1316.Sm off 1317.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW 1318.Sm on 1319Modifies the first occurrence of 1320.Ar old_string 1321in each word of the variable's value, replacing it with 1322.Ar new_string . 1323If a 1324.Ql g 1325is appended to the last delimiter of the pattern, all occurrences 1326in each word are replaced. 1327If a 1328.Ql 1 1329is appended to the last delimiter of the pattern, only the first occurrence 1330is affected. 1331If a 1332.Ql W 1333is appended to the last delimiter of the pattern, 1334then the value is treated as a single word 1335(possibly containing embedded white space). 1336If 1337.Ar old_string 1338begins with a caret 1339.Pq Ql ^ , 1340.Ar old_string 1341is anchored at the beginning of each word. 1342If 1343.Ar old_string 1344ends with a dollar sign 1345.Pq Ql \&$ , 1346it is anchored at the end of each word. 1347Inside 1348.Ar new_string , 1349an ampersand 1350.Pq Ql & 1351is replaced by 1352.Ar old_string 1353(without any 1354.Ql ^ 1355or 1356.Ql \&$ ) . 1357Any character may be used as a delimiter for the parts of the modifier 1358string. 1359The anchoring, ampersand and delimiter characters may be escaped with a 1360backslash 1361.Pq Ql \e . 1362.Pp 1363Variable expansion occurs in the normal fashion inside both 1364.Ar old_string 1365and 1366.Ar new_string 1367with the single exception that a backslash is used to prevent the expansion 1368of a dollar sign 1369.Pq Ql \&$ , 1370not a preceding dollar sign as is usual. 1371.Sm off 1372.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW 1373.Sm on 1374The 1375.Cm \&:C 1376modifier is just like the 1377.Cm \&:S 1378modifier except that the old and new strings, instead of being 1379simple strings, are an extended regular expression (see 1380.Xr regex 3 ) 1381string 1382.Ar pattern 1383and an 1384.Xr ed 1 Ns \-style 1385string 1386.Ar replacement . 1387Normally, the first occurrence of the pattern 1388.Ar pattern 1389in each word of the value is substituted with 1390.Ar replacement . 1391The 1392.Ql 1 1393modifier causes the substitution to apply to at most one word; the 1394.Ql g 1395modifier causes the substitution to apply to as many instances of the 1396search pattern 1397.Ar pattern 1398as occur in the word or words it is found in; the 1399.Ql W 1400modifier causes the value to be treated as a single word 1401(possibly containing embedded white space). 1402.Pp 1403As for the 1404.Cm \&:S 1405modifier, the 1406.Ar pattern 1407and 1408.Ar replacement 1409are subjected to variable expansion before being parsed as 1410regular expressions. 1411.It Cm \&:T 1412Replaces each word in the variable with its last path component. 1413.It Cm \&:u 1414Removes adjacent duplicate words (like 1415.Xr uniq 1 ) . 1416.Sm off 1417.It Cm \&:\&? Ar true_string Cm \&: Ar false_string 1418.Sm on 1419If the variable name (not its value), when parsed as a .if conditional 1420expression, evaluates to true, return as its value the 1421.Ar true_string , 1422otherwise return the 1423.Ar false_string . 1424Since the variable name is used as the expression, \&:\&? must be the 1425first modifier after the variable name itself - which will, of course, 1426usually contain variable expansions. 1427A common error is trying to use expressions like 1428.Dl ${NUMBERS:M42:?match:no} 1429which actually tests defined(NUMBERS), 1430to determine if any words match "42" you need to use something like: 1431.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} . 1432.It Ar :old_string=new_string 1433This is the 1434.At V 1435style variable substitution. 1436It must be the last modifier specified. 1437If 1438.Ar old_string 1439or 1440.Ar new_string 1441do not contain the pattern matching character 1442.Ar % 1443then it is assumed that they are 1444anchored at the end of each word, so only suffixes or entire 1445words may be replaced. 1446Otherwise 1447.Ar % 1448is the substring of 1449.Ar old_string 1450to be replaced in 1451.Ar new_string . 1452If only 1453.Ar old_string 1454contains the pattern matching character 1455.Ar % , 1456and 1457.Ar old_string 1458matches, then the result is the 1459.Ar new_string . 1460If only the 1461.Ar new_string 1462contains the pattern matching character 1463.Ar % , 1464then it is not treated specially and it is printed as a literal 1465.Ar % 1466on match. 1467If there is more than one pattern matching character 1468.Ar ( % ) 1469in either the 1470.Ar new_string 1471or 1472.Ar old_string , 1473only the first instance is treated specially (as the pattern character); 1474all subsequent instances are treated as regular characters. 1475.Pp 1476Variable expansion occurs in the normal fashion inside both 1477.Ar old_string 1478and 1479.Ar new_string 1480with the single exception that a backslash is used to prevent the 1481expansion of a dollar sign 1482.Pq Ql \&$ , 1483not a preceding dollar sign as is usual. 1484.Sm off 1485.It Cm \&:@ Ar temp Cm @ Ar string Cm @ 1486.Sm on 1487This is the loop expansion mechanism from the OSF Development 1488Environment (ODE) make. 1489Unlike 1490.Cm \&.for 1491loops, expansion occurs at the time of reference. 1492Assigns 1493.Ar temp 1494to each word in the variable and evaluates 1495.Ar string . 1496The ODE convention is that 1497.Ar temp 1498should start and end with a period. 1499For example. 1500.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@} 1501.Pp 1502However a single character variable is often more readable: 1503.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@} 1504.It Cm \&:_[=var] 1505Saves the current variable value in 1506.Ql $_ 1507or the named 1508.Va var 1509for later reference. 1510Example usage: 1511.Bd -literal -offset indent 1512M_cmpv.units = 1 1000 1000000 1513M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\ 1514\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh 1515 1516.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}} 1517 1518.Ed 1519Here 1520.Ql $_ 1521is used to save the result of the 1522.Ql :S 1523modifier which is later referenced using the index values from 1524.Ql :range . 1525.It Cm \&:U Ns Ar newval 1526If the variable is undefined, 1527.Ar newval 1528is the value. 1529If the variable is defined, the existing value is returned. 1530This is another ODE make feature. 1531It is handy for setting per-target CFLAGS for instance: 1532.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}} 1533If a value is only required if the variable is undefined, use: 1534.Dl ${VAR:D:Unewval} 1535.It Cm \&:D Ns Ar newval 1536If the variable is defined, 1537.Ar newval 1538is the value. 1539.It Cm \&:L 1540The name of the variable is the value. 1541.It Cm \&:P 1542The path of the node which has the same name as the variable 1543is the value. 1544If no such node exists or its path is null, then the 1545name of the variable is used. 1546In order for this modifier to work, the name (node) must at least have 1547appeared on the rhs of a dependency. 1548.Sm off 1549.It Cm \&:\&! Ar cmd Cm \&! 1550.Sm on 1551The output of running 1552.Ar cmd 1553is the value. 1554.It Cm \&:sh 1555If the variable is non-empty it is run as a command and the output 1556becomes the new value. 1557.It Cm \&::= Ns Ar str 1558The variable is assigned the value 1559.Ar str 1560after substitution. 1561This modifier and its variations are useful in 1562obscure situations such as wanting to set a variable when shell commands 1563are being parsed. 1564These assignment modifiers always expand to 1565nothing, so if appearing in a rule line by themselves should be 1566preceded with something to keep 1567.Nm 1568happy. 1569.Pp 1570The 1571.Ql Cm \&:: 1572helps avoid false matches with the 1573.At V 1574style 1575.Cm \&:= 1576modifier and since substitution always occurs the 1577.Cm \&::= 1578form is vaguely appropriate. 1579.It Cm \&::?= Ns Ar str 1580As for 1581.Cm \&::= 1582but only if the variable does not already have a value. 1583.It Cm \&::+= Ns Ar str 1584Append 1585.Ar str 1586to the variable. 1587.It Cm \&::!= Ns Ar cmd 1588Assign the output of 1589.Ar cmd 1590to the variable. 1591.It Cm \&:\&[ Ns Ar range Ns Cm \&] 1592Selects one or more words from the value, 1593or performs other operations related to the way in which the 1594value is divided into words. 1595.Pp 1596Ordinarily, a value is treated as a sequence of words 1597delimited by white space. 1598Some modifiers suppress this behavior, 1599causing a value to be treated as a single word 1600(possibly containing embedded white space). 1601An empty value, or a value that consists entirely of white-space, 1602is treated as a single word. 1603For the purposes of the 1604.Ql Cm \&:[] 1605modifier, the words are indexed both forwards using positive integers 1606(where index 1 represents the first word), 1607and backwards using negative integers 1608(where index \-1 represents the last word). 1609.Pp 1610The 1611.Ar range 1612is subjected to variable expansion, and the expanded result is 1613then interpreted as follows: 1614.Bl -tag -width index 1615.\" :[n] 1616.It Ar index 1617Selects a single word from the value. 1618.\" :[start..end] 1619.It Ar start Ns Cm \&.. Ns Ar end 1620Selects all words from 1621.Ar start 1622to 1623.Ar end , 1624inclusive. 1625For example, 1626.Ql Cm \&:[2..-1] 1627selects all words from the second word to the last word. 1628If 1629.Ar start 1630is greater than 1631.Ar end , 1632then the words are output in reverse order. 1633For example, 1634.Ql Cm \&:[-1..1] 1635selects all the words from last to first. 1636If the list is already ordered, then this effectively reverses 1637the list, but it is more efficient to use 1638.Ql Cm \&:Or 1639instead of 1640.Ql Cm \&:O:[-1..1] . 1641.\" :[*] 1642.It Cm \&* 1643Causes subsequent modifiers to treat the value as a single word 1644(possibly containing embedded white space). 1645Analogous to the effect of 1646\&"$*\&" 1647in Bourne shell. 1648.\" :[0] 1649.It 0 1650Means the same as 1651.Ql Cm \&:[*] . 1652.\" :[*] 1653.It Cm \&@ 1654Causes subsequent modifiers to treat the value as a sequence of words 1655delimited by white space. 1656Analogous to the effect of 1657\&"$@\&" 1658in Bourne shell. 1659.\" :[#] 1660.It Cm \&# 1661Returns the number of words in the value. 1662.El \" :[range] 1663.El 1664.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS 1665Makefile inclusion, conditional structures and for loops reminiscent 1666of the C programming language are provided in 1667.Nm . 1668All such structures are identified by a line beginning with a single 1669dot 1670.Pq Ql \&. 1671character. 1672Files are included with either 1673.Cm \&.include \&< Ns Ar file Ns Cm \&> 1674or 1675.Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q . 1676Variables between the angle brackets or double quotes are expanded 1677to form the file name. 1678If angle brackets are used, the included makefile is expected to be in 1679the system makefile directory. 1680If double quotes are used, the including makefile's directory and any 1681directories specified using the 1682.Fl I 1683option are searched before the system 1684makefile directory. 1685For compatibility with other versions of 1686.Nm 1687.Ql include file ... 1688is also accepted. 1689.Pp 1690If the include statement is written as 1691.Cm .-include 1692or as 1693.Cm .sinclude 1694then errors locating and/or opening include files are ignored. 1695.Pp 1696If the include statement is written as 1697.Cm .dinclude 1698not only are errors locating and/or opening include files ignored, 1699but stale dependencies within the included file will be ignored 1700just like 1701.Va .MAKE.DEPENDFILE . 1702.Pp 1703Conditional expressions are also preceded by a single dot as the first 1704character of a line. 1705The possible conditionals are as follows: 1706.Bl -tag -width Ds 1707.It Ic .error Ar message 1708The message is printed along with the name of the makefile and line number, 1709then 1710.Nm 1711will exit immediately. 1712.It Ic .export Ar variable ... 1713Export the specified global variable. 1714If no variable list is provided, all globals are exported 1715except for internal variables (those that start with 1716.Ql \&. ) . 1717This is not affected by the 1718.Fl X 1719flag, so should be used with caution. 1720For compatibility with other 1721.Nm 1722programs 1723.Ql export variable=value 1724is also accepted. 1725.Pp 1726Appending a variable name to 1727.Va .MAKE.EXPORTED 1728is equivalent to exporting a variable. 1729.It Ic .export-env Ar variable ... 1730The same as 1731.Ql .export , 1732except that the variable is not appended to 1733.Va .MAKE.EXPORTED . 1734This allows exporting a value to the environment which is different from that 1735used by 1736.Nm 1737internally. 1738.It Ic .export-literal Ar variable ... 1739The same as 1740.Ql .export-env , 1741except that variables in the value are not expanded. 1742.It Ic .info Ar message 1743The message is printed along with the name of the makefile and line number. 1744.It Ic .undef Ar variable 1745Un-define the specified global variable. 1746Only global variables may be un-defined. 1747.It Ic .unexport Ar variable ... 1748The opposite of 1749.Ql .export . 1750The specified global 1751.Va variable 1752will be removed from 1753.Va .MAKE.EXPORTED . 1754If no variable list is provided, all globals are unexported, 1755and 1756.Va .MAKE.EXPORTED 1757deleted. 1758.It Ic .unexport-env 1759Unexport all globals previously exported and 1760clear the environment inherited from the parent. 1761This operation will cause a memory leak of the original environment, 1762so should be used sparingly. 1763Testing for 1764.Va .MAKE.LEVEL 1765being 0, would make sense. 1766Also note that any variables which originated in the parent environment 1767should be explicitly preserved if desired. 1768For example: 1769.Bd -literal -offset indent 1770.Li .if ${.MAKE.LEVEL} == 0 1771PATH := ${PATH} 1772.Li .unexport-env 1773.Li .export PATH 1774.Li .endif 1775.Pp 1776.Ed 1777Would result in an environment containing only 1778.Ql Ev PATH , 1779which is the minimal useful environment. 1780Actually 1781.Ql Ev .MAKE.LEVEL 1782will also be pushed into the new environment. 1783.It Ic .warning Ar message 1784The message prefixed by 1785.Ql Pa warning: 1786is printed along with the name of the makefile and line number. 1787.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ... 1788Test the value of an expression. 1789.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1790Test the value of a variable. 1791.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1792Test the value of a variable. 1793.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1794Test the target being built. 1795.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ... 1796Test the target being built. 1797.It Ic .else 1798Reverse the sense of the last conditional. 1799.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ... 1800A combination of 1801.Ql Ic .else 1802followed by 1803.Ql Ic .if . 1804.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1805A combination of 1806.Ql Ic .else 1807followed by 1808.Ql Ic .ifdef . 1809.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1810A combination of 1811.Ql Ic .else 1812followed by 1813.Ql Ic .ifndef . 1814.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1815A combination of 1816.Ql Ic .else 1817followed by 1818.Ql Ic .ifmake . 1819.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1820A combination of 1821.Ql Ic .else 1822followed by 1823.Ql Ic .ifnmake . 1824.It Ic .endif 1825End the body of the conditional. 1826.El 1827.Pp 1828The 1829.Ar operator 1830may be any one of the following: 1831.Bl -tag -width "Cm XX" 1832.It Cm \&|\&| 1833Logical OR. 1834.It Cm \&&& 1835Logical 1836.Tn AND ; 1837of higher precedence than 1838.Dq \&|\&| . 1839.El 1840.Pp 1841As in C, 1842.Nm 1843will only evaluate a conditional as far as is necessary to determine 1844its value. 1845Parentheses may be used to change the order of evaluation. 1846The boolean operator 1847.Ql Ic \&! 1848may be used to logically negate an entire 1849conditional. 1850It is of higher precedence than 1851.Ql Ic \&&& . 1852.Pp 1853The value of 1854.Ar expression 1855may be any of the following: 1856.Bl -tag -width defined 1857.It Ic defined 1858Takes a variable name as an argument and evaluates to true if the variable 1859has been defined. 1860.It Ic make 1861Takes a target name as an argument and evaluates to true if the target 1862was specified as part of 1863.Nm Ns 's 1864command line or was declared the default target (either implicitly or 1865explicitly, see 1866.Va .MAIN ) 1867before the line containing the conditional. 1868.It Ic empty 1869Takes a variable, with possible modifiers, and evaluates to true if 1870the expansion of the variable would result in an empty string. 1871.It Ic exists 1872Takes a file name as an argument and evaluates to true if the file exists. 1873The file is searched for on the system search path (see 1874.Va .PATH ) . 1875.It Ic target 1876Takes a target name as an argument and evaluates to true if the target 1877has been defined. 1878.It Ic commands 1879Takes a target name as an argument and evaluates to true if the target 1880has been defined and has commands associated with it. 1881.El 1882.Pp 1883.Ar Expression 1884may also be an arithmetic or string comparison. 1885Variable expansion is 1886performed on both sides of the comparison, after which the integral 1887values are compared. 1888A value is interpreted as hexadecimal if it is 1889preceded by 0x, otherwise it is decimal; octal numbers are not supported. 1890The standard C relational operators are all supported. 1891If after 1892variable expansion, either the left or right hand side of a 1893.Ql Ic == 1894or 1895.Ql Ic "!=" 1896operator is not an integral value, then 1897string comparison is performed between the expanded 1898variables. 1899If no relational operator is given, it is assumed that the expanded 1900variable is being compared against 0, or an empty string in the case 1901of a string comparison. 1902.Pp 1903When 1904.Nm 1905is evaluating one of these conditional expressions, and it encounters 1906a (white-space separated) word it doesn't recognize, either the 1907.Dq make 1908or 1909.Dq defined 1910expression is applied to it, depending on the form of the conditional. 1911If the form is 1912.Ql Ic .ifdef , 1913.Ql Ic .ifndef , 1914or 1915.Ql Ic .if 1916the 1917.Dq defined 1918expression is applied. 1919Similarly, if the form is 1920.Ql Ic .ifmake 1921or 1922.Ql Ic .ifnmake , 1923the 1924.Dq make 1925expression is applied. 1926.Pp 1927If the conditional evaluates to true the parsing of the makefile continues 1928as before. 1929If it evaluates to false, the following lines are skipped. 1930In both cases this continues until a 1931.Ql Ic .else 1932or 1933.Ql Ic .endif 1934is found. 1935.Pp 1936For loops are typically used to apply a set of rules to a list of files. 1937The syntax of a for loop is: 1938.Pp 1939.Bl -tag -compact -width Ds 1940.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression 1941.It Aq make-lines 1942.It Ic \&.endfor 1943.El 1944.Pp 1945After the for 1946.Ic expression 1947is evaluated, it is split into words. 1948On each iteration of the loop, one word is taken and assigned to each 1949.Ic variable , 1950in order, and these 1951.Ic variables 1952are substituted into the 1953.Ic make-lines 1954inside the body of the for loop. 1955The number of words must come out even; that is, if there are three 1956iteration variables, the number of words provided must be a multiple 1957of three. 1958.Sh COMMENTS 1959Comments begin with a hash 1960.Pq Ql \&# 1961character, anywhere but in a shell 1962command line, and continue to the end of an unescaped new line. 1963.Sh SPECIAL SOURCES (ATTRIBUTES) 1964.Bl -tag -width .IGNOREx 1965.It Ic .EXEC 1966Target is never out of date, but always execute commands anyway. 1967.It Ic .IGNORE 1968Ignore any errors from the commands associated with this target, exactly 1969as if they all were preceded by a dash 1970.Pq Ql \- . 1971.\" .It Ic .INVISIBLE 1972.\" XXX 1973.\" .It Ic .JOIN 1974.\" XXX 1975.It Ic .MADE 1976Mark all sources of this target as being up-to-date. 1977.It Ic .MAKE 1978Execute the commands associated with this target even if the 1979.Fl n 1980or 1981.Fl t 1982options were specified. 1983Normally used to mark recursive 1984.Nm Ns s . 1985.It Ic .META 1986Create a meta file for the target, even if it is flagged as 1987.Ic .PHONY , 1988.Ic .MAKE , 1989or 1990.Ic .SPECIAL . 1991Usage in conjunction with 1992.Ic .MAKE 1993is the most likely case. 1994In "meta" mode, the target is out-of-date if the meta file is missing. 1995.It Ic .NOMETA 1996Do not create a meta file for the target. 1997Meta files are also not created for 1998.Ic .PHONY , 1999.Ic .MAKE , 2000or 2001.Ic .SPECIAL 2002targets. 2003.It Ic .NOMETA_CMP 2004Ignore differences in commands when deciding if target is out of date. 2005This is useful if the command contains a value which always changes. 2006If the number of commands change, though, the target will still be out of date. 2007The same effect applies to any command line that uses the variable 2008.Va .OODATE , 2009which can be used for that purpose even when not otherwise needed or desired: 2010.Bd -literal -offset indent 2011 2012skip-compare-for-some: 2013 @echo this will be compared 2014 @echo this will not ${.OODATE:M.NOMETA_CMP} 2015 @echo this will also be compared 2016 2017.Ed 2018The 2019.Cm \&:M 2020pattern suppresses any expansion of the unwanted variable. 2021.It Ic .NOPATH 2022Do not search for the target in the directories specified by 2023.Ic .PATH . 2024.It Ic .NOTMAIN 2025Normally 2026.Nm 2027selects the first target it encounters as the default target to be built 2028if no target was specified. 2029This source prevents this target from being selected. 2030.It Ic .OPTIONAL 2031If a target is marked with this attribute and 2032.Nm 2033can't figure out how to create it, it will ignore this fact and assume 2034the file isn't needed or already exists. 2035.It Ic .PHONY 2036The target does not 2037correspond to an actual file; it is always considered to be out of date, 2038and will not be created with the 2039.Fl t 2040option. 2041Suffix-transformation rules are not applied to 2042.Ic .PHONY 2043targets. 2044.It Ic .PRECIOUS 2045When 2046.Nm 2047is interrupted, it normally removes any partially made targets. 2048This source prevents the target from being removed. 2049.It Ic .RECURSIVE 2050Synonym for 2051.Ic .MAKE . 2052.It Ic .SILENT 2053Do not echo any of the commands associated with this target, exactly 2054as if they all were preceded by an at sign 2055.Pq Ql @ . 2056.It Ic .USE 2057Turn the target into 2058.Nm Ns 's 2059version of a macro. 2060When the target is used as a source for another target, the other target 2061acquires the commands, sources, and attributes (except for 2062.Ic .USE ) 2063of the 2064source. 2065If the target already has commands, the 2066.Ic .USE 2067target's commands are appended 2068to them. 2069.It Ic .USEBEFORE 2070Exactly like 2071.Ic .USE , 2072but prepend the 2073.Ic .USEBEFORE 2074target commands to the target. 2075.It Ic .WAIT 2076If 2077.Ic .WAIT 2078appears in a dependency line, the sources that precede it are 2079made before the sources that succeed it in the line. 2080Since the dependents of files are not made until the file itself 2081could be made, this also stops the dependents being built unless they 2082are needed for another branch of the dependency tree. 2083So given: 2084.Bd -literal 2085x: a .WAIT b 2086 echo x 2087a: 2088 echo a 2089b: b1 2090 echo b 2091b1: 2092 echo b1 2093 2094.Ed 2095the output is always 2096.Ql a , 2097.Ql b1 , 2098.Ql b , 2099.Ql x . 2100.br 2101The ordering imposed by 2102.Ic .WAIT 2103is only relevant for parallel makes. 2104.El 2105.Sh SPECIAL TARGETS 2106Special targets may not be included with other targets, i.e. they must be 2107the only target specified. 2108.Bl -tag -width .BEGINx 2109.It Ic .BEGIN 2110Any command lines attached to this target are executed before anything 2111else is done. 2112.It Ic .DEFAULT 2113This is sort of a 2114.Ic .USE 2115rule for any target (that was used only as a 2116source) that 2117.Nm 2118can't figure out any other way to create. 2119Only the shell script is used. 2120The 2121.Ic .IMPSRC 2122variable of a target that inherits 2123.Ic .DEFAULT Ns 's 2124commands is set 2125to the target's own name. 2126.It Ic .DELETE_ON_ERROR 2127If this target is present in the makefile, it globally causes make to 2128delete targets whose commands fail. 2129(By default, only targets whose commands are interrupted during 2130execution are deleted. 2131This is the historical behavior.) 2132This setting can be used to help prevent half-finished or malformed 2133targets from being left around and corrupting future rebuilds. 2134.It Ic .END 2135Any command lines attached to this target are executed after everything 2136else is done. 2137.It Ic .ERROR 2138Any command lines attached to this target are executed when another target fails. 2139The 2140.Ic .ERROR_TARGET 2141variable is set to the target that failed. 2142See also 2143.Ic MAKE_PRINT_VAR_ON_ERROR . 2144.It Ic .IGNORE 2145Mark each of the sources with the 2146.Ic .IGNORE 2147attribute. 2148If no sources are specified, this is the equivalent of specifying the 2149.Fl i 2150option. 2151.It Ic .INTERRUPT 2152If 2153.Nm 2154is interrupted, the commands for this target will be executed. 2155.It Ic .MAIN 2156If no target is specified when 2157.Nm 2158is invoked, this target will be built. 2159.It Ic .MAKEFLAGS 2160This target provides a way to specify flags for 2161.Nm 2162when the makefile is used. 2163The flags are as if typed to the shell, though the 2164.Fl f 2165option will have 2166no effect. 2167.\" XXX: NOT YET!!!! 2168.\" .It Ic .NOTPARALLEL 2169.\" The named targets are executed in non parallel mode. 2170.\" If no targets are 2171.\" specified, then all targets are executed in non parallel mode. 2172.It Ic .NOPATH 2173Apply the 2174.Ic .NOPATH 2175attribute to any specified sources. 2176.It Ic .NOTPARALLEL 2177Disable parallel mode. 2178.It Ic .NO_PARALLEL 2179Synonym for 2180.Ic .NOTPARALLEL , 2181for compatibility with other pmake variants. 2182.It Ic .OBJDIR 2183The source is a new value for 2184.Ql Va .OBJDIR . 2185If it exists, 2186.Nm 2187will 2188.Xr chdir 2 2189to it and update the value of 2190.Ql Va .OBJDIR . 2191.It Ic .ORDER 2192The named targets are made in sequence. 2193This ordering does not add targets to the list of targets to be made. 2194Since the dependents of a target do not get built until the target itself 2195could be built, unless 2196.Ql a 2197is built by another part of the dependency graph, 2198the following is a dependency loop: 2199.Bd -literal 2200\&.ORDER: b a 2201b: a 2202.Ed 2203.Pp 2204The ordering imposed by 2205.Ic .ORDER 2206is only relevant for parallel makes. 2207.\" XXX: NOT YET!!!! 2208.\" .It Ic .PARALLEL 2209.\" The named targets are executed in parallel mode. 2210.\" If no targets are 2211.\" specified, then all targets are executed in parallel mode. 2212.It Ic .PATH 2213The sources are directories which are to be searched for files not 2214found in the current directory. 2215If no sources are specified, any previously specified directories are 2216deleted. 2217If the source is the special 2218.Ic .DOTLAST 2219target, then the current working 2220directory is searched last. 2221.It Ic .PATH. Ns Va suffix 2222Like 2223.Ic .PATH 2224but applies only to files with a particular suffix. 2225The suffix must have been previously declared with 2226.Ic .SUFFIXES . 2227.It Ic .PHONY 2228Apply the 2229.Ic .PHONY 2230attribute to any specified sources. 2231.It Ic .PRECIOUS 2232Apply the 2233.Ic .PRECIOUS 2234attribute to any specified sources. 2235If no sources are specified, the 2236.Ic .PRECIOUS 2237attribute is applied to every 2238target in the file. 2239.It Ic .SHELL 2240Sets the shell that 2241.Nm 2242will use to execute commands. 2243The sources are a set of 2244.Ar field=value 2245pairs. 2246.Bl -tag -width hasErrCtls 2247.It Ar name 2248This is the minimal specification, used to select one of the built-in 2249shell specs; 2250.Ar sh , 2251.Ar ksh , 2252and 2253.Ar csh . 2254.It Ar path 2255Specifies the path to the shell. 2256.It Ar hasErrCtl 2257Indicates whether the shell supports exit on error. 2258.It Ar check 2259The command to turn on error checking. 2260.It Ar ignore 2261The command to disable error checking. 2262.It Ar echo 2263The command to turn on echoing of commands executed. 2264.It Ar quiet 2265The command to turn off echoing of commands executed. 2266.It Ar filter 2267The output to filter after issuing the 2268.Ar quiet 2269command. 2270It is typically identical to 2271.Ar quiet . 2272.It Ar errFlag 2273The flag to pass the shell to enable error checking. 2274.It Ar echoFlag 2275The flag to pass the shell to enable command echoing. 2276.It Ar newline 2277The string literal to pass the shell that results in a single newline 2278character when used outside of any quoting characters. 2279.El 2280Example: 2281.Bd -literal 2282\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e 2283 check="set \-e" ignore="set +e" \e 2284 echo="set \-v" quiet="set +v" filter="set +v" \e 2285 echoFlag=v errFlag=e newline="'\en'" 2286.Ed 2287.It Ic .SILENT 2288Apply the 2289.Ic .SILENT 2290attribute to any specified sources. 2291If no sources are specified, the 2292.Ic .SILENT 2293attribute is applied to every 2294command in the file. 2295.It Ic .STALE 2296This target gets run when a dependency file contains stale entries, having 2297.Va .ALLSRC 2298set to the name of that dependency file. 2299.It Ic .SUFFIXES 2300Each source specifies a suffix to 2301.Nm . 2302If no sources are specified, any previously specified suffixes are deleted. 2303It allows the creation of suffix-transformation rules. 2304.Pp 2305Example: 2306.Bd -literal 2307\&.SUFFIXES: .o 2308\&.c.o: 2309 cc \-o ${.TARGET} \-c ${.IMPSRC} 2310.Ed 2311.El 2312.Sh ENVIRONMENT 2313.Nm 2314uses the following environment variables, if they exist: 2315.Ev MACHINE , 2316.Ev MACHINE_ARCH , 2317.Ev MAKE , 2318.Ev MAKEFLAGS , 2319.Ev MAKEOBJDIR , 2320.Ev MAKEOBJDIRPREFIX , 2321.Ev MAKESYSPATH , 2322.Ev PWD , 2323and 2324.Ev TMPDIR . 2325.Pp 2326.Ev MAKEOBJDIRPREFIX 2327and 2328.Ev MAKEOBJDIR 2329may only be set in the environment or on the command line to 2330.Nm 2331and not as makefile variables; 2332see the description of 2333.Ql Va .OBJDIR 2334for more details. 2335.Sh FILES 2336.Bl -tag -width /usr/share/mk -compact 2337.It .depend 2338list of dependencies 2339.It Makefile 2340list of dependencies 2341.It makefile 2342list of dependencies 2343.It sys.mk 2344system makefile 2345.It /usr/share/mk 2346system makefile directory 2347.El 2348.Sh COMPATIBILITY 2349The basic make syntax is compatible between different versions of make; 2350however the special variables, variable modifiers and conditionals are not. 2351.Ss Older versions 2352An incomplete list of changes in older versions of 2353.Nm : 2354.Pp 2355The way that .for loop variables are substituted changed after 2356.Nx 5.0 2357so that they still appear to be variable expansions. 2358In particular this stops them being treated as syntax, and removes some 2359obscure problems using them in .if statements. 2360.Pp 2361The way that parallel makes are scheduled changed in 2362.Nx 4.0 2363so that .ORDER and .WAIT apply recursively to the dependent nodes. 2364The algorithms used may change again in the future. 2365.Ss Other make dialects 2366Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not 2367support most of the features of 2368.Nm 2369as described in this manual. 2370Most notably: 2371.Bl -bullet -offset indent 2372.It 2373The 2374.Ic .WAIT 2375and 2376.Ic .ORDER 2377declarations and most functionality pertaining to parallelization. 2378(GNU make supports parallelization but lacks these features needed to 2379control it effectively.) 2380.It 2381Directives, including for loops and conditionals and most of the 2382forms of include files. 2383(GNU make has its own incompatible and less powerful syntax for 2384conditionals.) 2385.It 2386All built-in variables that begin with a dot. 2387.It 2388Most of the special sources and targets that begin with a dot, 2389with the notable exception of 2390.Ic .PHONY , 2391.Ic .PRECIOUS , 2392and 2393.Ic .SUFFIXES . 2394.It 2395Variable modifiers, except for the 2396.Dl :old=new 2397string substitution, which does not portably support globbing with 2398.Ql % 2399and historically only works on declared suffixes. 2400.It 2401The 2402.Ic $> 2403variable even in its short form; most makes support this functionality 2404but its name varies. 2405.El 2406.Pp 2407Some features are somewhat more portable, such as assignment with 2408.Ic += , 2409.Ic ?= , 2410and 2411.Ic != . 2412The 2413.Ic .PATH 2414functionality is based on an older feature 2415.Ic VPATH 2416found in GNU make and many versions of SVR4 make; however, 2417historically its behavior is too ill-defined (and too buggy) to rely 2418upon. 2419.Pp 2420The 2421.Ic $@ 2422and 2423.Ic $< 2424variables are more or less universally portable, as is the 2425.Ic $(MAKE) 2426variable. 2427Basic use of suffix rules (for files only in the current directory, 2428not trying to chain transformations together, etc.) is also reasonably 2429portable. 2430.Sh SEE ALSO 2431.Xr mkdep 1 , 2432.Xr style.Makefile 5 2433.Sh HISTORY 2434A 2435.Nm 2436command appeared in 2437.At v7 . 2438This 2439.Nm 2440implementation is based on Adam De Boor's pmake program which was written 2441for Sprite at Berkeley. 2442It was designed to be a parallel distributed make running jobs on different 2443machines using a daemon called 2444.Dq customs . 2445.Pp 2446Historically the target/dependency 2447.Dq FRC 2448has been used to FoRCe rebuilding (since the target/dependency 2449does not exist... unless someone creates an 2450.Dq FRC 2451file). 2452.Sh BUGS 2453The 2454.Nm 2455syntax is difficult to parse without actually acting on the data. 2456For instance, finding the end of a variable's use should involve scanning 2457each of the modifiers, using the correct terminator for each field. 2458In many places 2459.Nm 2460just counts {} and () in order to find the end of a variable expansion. 2461.Pp 2462There is no way of escaping a space character in a filename. 2463