1.\" $NetBSD: make.1,v 1.296 2021/02/04 21:42:46 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 December 22, 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 BeikNnqrSstWwX 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 scope. 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 333Stop processing if an error is encountered. 334This is the default behavior and the opposite of 335.Fl k . 336.It Fl s 337Do not echo any commands as they are executed. 338Equivalent to specifying 339.Ql Ic @ 340before each command line in the makefile. 341.It Fl T Ar tracefile 342When used with the 343.Fl j 344flag, 345append a trace record to 346.Ar tracefile 347for each job started and completed. 348.It Fl t 349Rather than re-building a target as specified in the makefile, create it 350or update its modification time to make it appear up-to-date. 351.It Fl V Ar variable 352Print the value of 353.Ar variable . 354Do not build any targets. 355Multiple instances of this option may be specified; 356the variables will be printed one per line, 357with a blank line for each null or undefined variable. 358The value printed is extracted from the global scope after all 359makefiles have been read. 360By default, the raw variable contents (which may 361include additional unexpanded variable references) are shown. 362If 363.Ar variable 364contains a 365.Ql \&$ 366then the value will be recursively expanded to its complete resultant 367text before printing. 368The expanded value will also be printed if 369.Va .MAKE.EXPAND_VARIABLES 370is set to true and 371the 372.Fl dV 373option has not been used to override it. 374Note that loop-local and target-local variables, as well as values 375taken temporarily by global variables during makefile processing, are 376not accessible via this option. 377The 378.Fl dv 379debug mode can be used to see these at the cost of generating 380substantial extraneous output. 381.It Fl v Ar variable 382Like 383.Fl V 384but the variable is always expanded to its complete value. 385.It Fl W 386Treat any warnings during makefile parsing as errors. 387.It Fl w 388Print entering and leaving directory messages, pre and post processing. 389.It Fl X 390Don't export variables passed on the command line to the environment 391individually. 392Variables passed on the command line are still exported 393via the 394.Va MAKEFLAGS 395environment variable. 396This option may be useful on systems which have a small limit on the 397size of command arguments. 398.It Ar variable=value 399Set the value of the variable 400.Ar variable 401to 402.Ar value . 403Normally, all values passed on the command line are also exported to 404sub-makes in the environment. 405The 406.Fl X 407flag disables this behavior. 408Variable assignments should follow options for POSIX compatibility 409but no ordering is enforced. 410.El 411.Pp 412There are seven different types of lines in a makefile: file dependency 413specifications, shell commands, variable assignments, include statements, 414conditional directives, for loops, and comments. 415.Pp 416In general, lines may be continued from one line to the next by ending 417them with a backslash 418.Pq Ql \e . 419The trailing newline character and initial whitespace on the following 420line are compressed into a single space. 421.Sh FILE DEPENDENCY SPECIFICATIONS 422Dependency lines consist of one or more targets, an operator, and zero 423or more sources. 424This creates a relationship where the targets 425.Dq depend 426on the sources 427and are customarily created from them. 428A target is considered out-of-date if it does not exist, or if its 429modification time is less than that of any of its sources. 430An out-of-date target will be re-created, but not until all sources 431have been examined and themselves re-created as needed. 432Three operators may be used: 433.Bl -tag -width flag 434.It Ic \&: 435Many dependency lines may name this target but only one may have 436attached shell commands. 437All sources named in all dependency lines are considered together, 438and if needed the attached shell commands are run to create or 439re-create the target. 440If 441.Nm 442is interrupted, the target is removed. 443.It Ic \&! 444The same, but the target is always re-created whether or not it is out 445of date. 446.It Ic \&:: 447Any dependency line may have attached shell commands, but each one 448is handled independently: its sources are considered and the attached 449shell commands are run if the target is out of date with respect to 450(only) those sources. 451Thus, different groups of the attached shell commands may be run 452depending on the circumstances. 453Furthermore, unlike 454.Ic \&:, 455for dependency lines with no sources, the attached shell 456commands are always run. 457Also unlike 458.Ic \&:, 459the target will not be removed if 460.Nm 461is interrupted. 462.El 463All dependency lines mentioning a particular target must use the same 464operator. 465.Pp 466Targets and sources may contain the shell wildcard values 467.Ql \&? , 468.Ql * , 469.Ql [] , 470and 471.Ql {} . 472The values 473.Ql \&? , 474.Ql * , 475and 476.Ql [] 477may only be used as part of the final 478component of the target or source, and must be used to describe existing 479files. 480The value 481.Ql {} 482need not necessarily be used to describe existing files. 483Expansion is in directory order, not alphabetically as done in the shell. 484.Sh SHELL COMMANDS 485Each target may have associated with it one or more lines of shell 486commands, normally 487used to create the target. 488Each of the lines in this script 489.Em must 490be preceded by a tab. 491(For historical reasons, spaces are not accepted.) 492While targets can appear in many dependency lines if desired, by 493default only one of these rules may be followed by a creation 494script. 495If the 496.Ql Ic \&:: 497operator is used, however, all rules may include scripts and the 498scripts are executed in the order found. 499.Pp 500Each line is treated as a separate shell command, unless the end of 501line is escaped with a backslash 502.Pq Ql \e 503in which case that line and the next are combined. 504.\" The escaped newline is retained and passed to the shell, which 505.\" normally ignores it. 506.\" However, the tab at the beginning of the following line is removed. 507If the first characters of the command are any combination of 508.Ql Ic @ , 509.Ql Ic + , 510or 511.Ql Ic \- , 512the command is treated specially. 513A 514.Ql Ic @ 515causes the command not to be echoed before it is executed. 516A 517.Ql Ic + 518causes the command to be executed even when 519.Fl n 520is given. 521This is similar to the effect of the .MAKE special source, 522except that the effect can be limited to a single line of a script. 523A 524.Ql Ic \- 525in compatibility mode 526causes any non-zero exit status of the command line to be ignored. 527.Pp 528When 529.Nm 530is run in jobs mode with 531.Fl j Ar max_jobs , 532the entire script for the target is fed to a 533single instance of the shell. 534In compatibility (non-jobs) mode, each command is run in a separate process. 535If the command contains any shell meta characters 536.Pq Ql #=|^(){};&<>*?[]:$`\e\en 537it will be passed to the shell; otherwise 538.Nm 539will attempt direct execution. 540If a line starts with 541.Ql Ic \- 542and the shell has ErrCtl enabled then failure of the command line 543will be ignored as in compatibility mode. 544Otherwise 545.Ql Ic \- 546affects the entire job; 547the script will stop at the first command line that fails, 548but the target will not be deemed to have failed. 549.Pp 550Makefiles should be written so that the mode of 551.Nm 552operation does not change their behavior. 553For example, any command which needs to use 554.Dq cd 555or 556.Dq chdir 557without potentially changing the directory for subsequent commands 558should be put in parentheses so it executes in a subshell. 559To force the use of one shell, escape the line breaks so as to make 560the whole script one command. 561For example: 562.Bd -literal -offset indent 563avoid-chdir-side-effects: 564 @echo Building $@ in `pwd` 565 @(cd ${.CURDIR} && ${MAKE} $@) 566 @echo Back in `pwd` 567 568ensure-one-shell-regardless-of-mode: 569 @echo Building $@ in `pwd`; \e 570 (cd ${.CURDIR} && ${MAKE} $@); \e 571 echo Back in `pwd` 572.Ed 573.Pp 574Since 575.Nm 576will 577.Xr chdir 2 578to 579.Ql Va .OBJDIR 580before executing any targets, each child process 581starts with that as its current working directory. 582.Sh VARIABLE ASSIGNMENTS 583Variables in make are much like variables in the shell, and, by tradition, 584consist of all upper-case letters. 585.Ss Variable assignment modifiers 586The five operators that can be used to assign values to variables are as 587follows: 588.Bl -tag -width Ds 589.It Ic \&= 590Assign the value to the variable. 591Any previous value is overridden. 592.It Ic \&+= 593Append the value to the current value of the variable. 594.It Ic \&?= 595Assign the value to the variable if it is not already defined. 596.It Ic \&:= 597Assign with expansion, i.e. expand the value before assigning it 598to the variable. 599Normally, expansion is not done until the variable is referenced. 600.Em NOTE : 601References to undefined variables are 602.Em not 603expanded. 604This can cause problems when variable modifiers are used. 605.It Ic \&!= 606Expand the value and pass it to the shell for execution and assign 607the result to the variable. 608Any newlines in the result are replaced with spaces. 609.El 610.Pp 611Any white-space before the assigned 612.Ar value 613is removed; if the value is being appended, a single space is inserted 614between the previous contents of the variable and the appended value. 615.Pp 616Variables are expanded by surrounding the variable name with either 617curly braces 618.Pq Ql {} 619or parentheses 620.Pq Ql () 621and preceding it with 622a dollar sign 623.Pq Ql \&$ . 624If the variable name contains only a single letter, the surrounding 625braces or parentheses are not required. 626This shorter form is not recommended. 627.Pp 628If the variable name contains a dollar, then the name itself is expanded first. 629This allows almost arbitrary variable names, however names containing dollar, 630braces, parentheses, or whitespace are really best avoided! 631.Pp 632If the result of expanding a variable contains a dollar sign 633.Pq Ql \&$ 634the string is expanded again. 635.Pp 636Variable substitution occurs at three distinct times, depending on where 637the variable is being used. 638.Bl -enum 639.It 640Variables in dependency lines are expanded as the line is read. 641.It 642Variables in shell commands are expanded when the shell command is 643executed. 644.It 645.Dq .for 646loop index variables are expanded on each loop iteration. 647Note that other variables are not expanded inside loops so 648the following example code: 649.Bd -literal -offset indent 650 651.Dv .for i in 1 2 3 652a+= ${i} 653j= ${i} 654b+= ${j} 655.Dv .endfor 656 657all: 658 @echo ${a} 659 @echo ${b} 660 661.Ed 662will print: 663.Bd -literal -offset indent 6641 2 3 6653 3 3 666 667.Ed 668Because while ${a} contains 669.Dq 1 2 3 670after the loop is executed, ${b} 671contains 672.Dq ${j} ${j} ${j} 673which expands to 674.Dq 3 3 3 675since after the loop completes ${j} contains 676.Dq 3 . 677.El 678.Ss Variable classes 679The four different classes of variables (in order of increasing precedence) 680are: 681.Bl -tag -width Ds 682.It Environment variables 683Variables defined as part of 684.Nm Ns 's 685environment. 686.It Global variables 687Variables defined in the makefile or in included makefiles. 688.It Command line variables 689Variables defined as part of the command line. 690.It Local variables 691Variables that are defined specific to a certain target. 692.El 693.Pp 694Local variables are all built in and their values vary magically from 695target to target. 696It is not currently possible to define new local variables. 697The seven local variables are as follows: 698.Bl -tag -width ".ARCHIVE" -offset indent 699.It Va .ALLSRC 700The list of all sources for this target; also known as 701.Ql Va \&> . 702.It Va .ARCHIVE 703The name of the archive file; also known as 704.Ql Va \&! . 705.It Va .IMPSRC 706In suffix-transformation rules, the name/path of the source from which the 707target is to be transformed (the 708.Dq implied 709source); also known as 710.Ql Va \&< . 711It is not defined in explicit rules. 712.It Va .MEMBER 713The name of the archive member; also known as 714.Ql Va % . 715.It Va .OODATE 716The list of sources for this target that were deemed out-of-date; also 717known as 718.Ql Va \&? . 719.It Va .PREFIX 720The file prefix of the target, containing only the file portion, no suffix 721or preceding directory components; also known as 722.Ql Va * . 723The suffix must be one of the known suffixes declared with 724.Ic .SUFFIXES 725or it will not be recognized. 726.It Va .TARGET 727The name of the target; also known as 728.Ql Va @ . 729For compatibility with other makes this is an alias for 730.Ic .ARCHIVE 731in archive member rules. 732.El 733.Pp 734The shorter forms 735.Ql ( Va > , 736.Ql Va \&! , 737.Ql Va < , 738.Ql Va % , 739.Ql Va \&? , 740.Ql Va * , 741and 742.Ql Va @ ) 743are permitted for backward 744compatibility with historical makefiles and legacy POSIX make and are 745not recommended. 746.Pp 747Variants of these variables with the punctuation followed immediately by 748.Ql D 749or 750.Ql F , 751e.g. 752.Ql Va $(@D) , 753are legacy forms equivalent to using the 754.Ql :H 755and 756.Ql :T 757modifiers. 758These forms are accepted for compatibility with 759.At V 760makefiles and POSIX but are not recommended. 761.Pp 762Four of the local variables may be used in sources on dependency lines 763because they expand to the proper value for each target on the line. 764These variables are 765.Ql Va .TARGET , 766.Ql Va .PREFIX , 767.Ql Va .ARCHIVE , 768and 769.Ql Va .MEMBER . 770.Ss Additional built-in variables 771In addition, 772.Nm 773sets or knows about the following variables: 774.Bl -tag -width .MAKEOVERRIDES 775.It Va \&$ 776A single dollar sign 777.Ql \&$ , 778i.e. 779.Ql \&$$ 780expands to a single dollar 781sign. 782.It Va .ALLTARGETS 783The list of all targets encountered in the Makefile. 784If evaluated during 785Makefile parsing, lists only those targets encountered thus far. 786.It Va .CURDIR 787A path to the directory where 788.Nm 789was executed. 790Refer to the description of 791.Ql Ev PWD 792for more details. 793.It Va .INCLUDEDFROMDIR 794The directory of the file this Makefile was included from. 795.It Va .INCLUDEDFROMFILE 796The filename of the file this Makefile was included from. 797.It Ev MAKE 798The name that 799.Nm 800was executed with 801.Pq Va argv[0] . 802For compatibility 803.Nm 804also sets 805.Va .MAKE 806with the same value. 807The preferred variable to use is the environment variable 808.Ev MAKE 809because it is more compatible with other versions of 810.Nm 811and cannot be confused with the special target with the same name. 812.It Va .MAKE.DEPENDFILE 813Names the makefile (default 814.Ql Pa .depend ) 815from which generated dependencies are read. 816.It Va .MAKE.EXPAND_VARIABLES 817A boolean that controls the default behavior of the 818.Fl V 819option. 820If true, variable values printed with 821.Fl V 822are fully expanded; if false, the raw variable contents (which may 823include additional unexpanded variable references) are shown. 824.It Va .MAKE.EXPORTED 825The list of variables exported by 826.Nm . 827.It Va .MAKE.JOBS 828The argument to the 829.Fl j 830option. 831.It Va .MAKE.JOB.PREFIX 832If 833.Nm 834is run with 835.Ar j 836then output for each target is prefixed with a token 837.Ql --- target --- 838the first part of which can be controlled via 839.Va .MAKE.JOB.PREFIX . 840If 841.Va .MAKE.JOB.PREFIX 842is empty, no token is printed. 843.br 844For example: 845.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}] 846would produce tokens like 847.Ql ---make[1234] target --- 848making it easier to track the degree of parallelism being achieved. 849.It Ev MAKEFLAGS 850The environment variable 851.Ql Ev MAKEFLAGS 852may contain anything that 853may be specified on 854.Nm Ns 's 855command line. 856Anything specified on 857.Nm Ns 's 858command line is appended to the 859.Ql Ev MAKEFLAGS 860variable which is then 861entered into the environment for all programs which 862.Nm 863executes. 864.It Va .MAKE.LEVEL 865The recursion depth of 866.Nm . 867The initial instance of 868.Nm 869will be 0, and an incremented value is put into the environment 870to be seen by the next generation. 871This allows tests like: 872.Li .if ${.MAKE.LEVEL} == 0 873to protect things which should only be evaluated in the initial instance of 874.Nm . 875.It Va .MAKE.MAKEFILE_PREFERENCE 876The ordered list of makefile names 877(default 878.Ql Pa makefile , 879.Ql Pa Makefile ) 880that 881.Nm 882will look for. 883.It Va .MAKE.MAKEFILES 884The list of makefiles read by 885.Nm , 886which is useful for tracking dependencies. 887Each makefile is recorded only once, regardless of the number of times read. 888.It Va .MAKE.MODE 889Processed after reading all makefiles. 890Can affect the mode that 891.Nm 892runs in. 893It can contain a number of keywords: 894.Bl -hang -width missing-filemon=bf. 895.It Pa compat 896Like 897.Fl B , 898puts 899.Nm 900into "compat" mode. 901.It Pa meta 902Puts 903.Nm 904into "meta" mode, where meta files are created for each target 905to capture the command run, the output generated and if 906.Xr filemon 4 907is available, the system calls which are of interest to 908.Nm . 909The captured output can be very useful when diagnosing errors. 910.It Pa curdirOk= Ar bf 911Normally 912.Nm 913will not create .meta files in 914.Ql Va .CURDIR . 915This can be overridden by setting 916.Va bf 917to a value which represents True. 918.It Pa missing-meta= Ar bf 919If 920.Va bf 921is True, then a missing .meta file makes the target out-of-date. 922.It Pa missing-filemon= Ar bf 923If 924.Va bf 925is True, then missing filemon data makes the target out-of-date. 926.It Pa nofilemon 927Do not use 928.Xr filemon 4 . 929.It Pa env 930For debugging, it can be useful to include the environment 931in the .meta file. 932.It Pa verbose 933If in "meta" mode, print a clue about the target being built. 934This is useful if the build is otherwise running silently. 935The message printed the value of: 936.Va .MAKE.META.PREFIX . 937.It Pa ignore-cmd 938Some makefiles have commands which are simply not stable. 939This keyword causes them to be ignored for 940determining whether a target is out of date in "meta" mode. 941See also 942.Ic .NOMETA_CMP . 943.It Pa silent= Ar bf 944If 945.Va bf 946is True, when a .meta file is created, mark the target 947.Ic .SILENT . 948.El 949.It Va .MAKE.META.BAILIWICK 950In "meta" mode, provides a list of prefixes which 951match the directories controlled by 952.Nm . 953If a file that was generated outside of 954.Va .OBJDIR 955but within said bailiwick is missing, 956the current target is considered out-of-date. 957.It Va .MAKE.META.CREATED 958In "meta" mode, this variable contains a list of all the meta files 959updated. 960If not empty, it can be used to trigger processing of 961.Va .MAKE.META.FILES . 962.It Va .MAKE.META.FILES 963In "meta" mode, this variable contains a list of all the meta files 964used (updated or not). 965This list can be used to process the meta files to extract dependency 966information. 967.It Va .MAKE.META.IGNORE_PATHS 968Provides a list of path prefixes that should be ignored; 969because the contents are expected to change over time. 970The default list includes: 971.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp 972.It Va .MAKE.META.IGNORE_PATTERNS 973Provides a list of patterns to match against pathnames. 974Ignore any that match. 975.It Va .MAKE.META.IGNORE_FILTER 976Provides a list of variable modifiers to apply to each pathname. 977Ignore if the expansion is an empty string. 978.It Va .MAKE.META.PREFIX 979Defines the message printed for each meta file updated in "meta verbose" mode. 980The default value is: 981.Dl Building ${.TARGET:H:tA}/${.TARGET:T} 982.It Va .MAKEOVERRIDES 983This variable is used to record the names of variables assigned to 984on the command line, so that they may be exported as part of 985.Ql Ev MAKEFLAGS . 986This behavior can be disabled by assigning an empty value to 987.Ql Va .MAKEOVERRIDES 988within a makefile. 989Extra variables can be exported from a makefile 990by appending their names to 991.Ql Va .MAKEOVERRIDES . 992.Ql Ev MAKEFLAGS 993is re-exported whenever 994.Ql Va .MAKEOVERRIDES 995is modified. 996.It Va .MAKE.PATH_FILEMON 997If 998.Nm 999was built with 1000.Xr filemon 4 1001support, this is set to the path of the device node. 1002This allows makefiles to test for this support. 1003.It Va .MAKE.PID 1004The process-id of 1005.Nm . 1006.It Va .MAKE.PPID 1007The parent process-id of 1008.Nm . 1009.It Va .MAKE.SAVE_DOLLARS 1010value should be a boolean that controls whether 1011.Ql $$ 1012are preserved when doing 1013.Ql := 1014assignments. 1015The default is true, for compatibility with other makes. 1016If set to false, 1017.Ql $$ 1018becomes 1019.Ql $ 1020per normal evaluation rules. 1021.It Va .MAKE.UID 1022The user-id running 1023.Nm . 1024.It Va .MAKE.GID 1025The group-id running 1026.Nm . 1027.It Va MAKE_PRINT_VAR_ON_ERROR 1028When 1029.Nm 1030stops due to an error, it sets 1031.Ql Va .ERROR_TARGET 1032to the name of the target that failed, 1033.Ql Va .ERROR_CMD 1034to the commands of the failed target, 1035and in "meta" mode, it also sets 1036.Ql Va .ERROR_CWD 1037to the 1038.Xr getcwd 3 , 1039and 1040.Ql Va .ERROR_META_FILE 1041to the path of the meta file (if any) describing the failed target. 1042It then prints its name and the value of 1043.Ql Va .CURDIR 1044as well as the value of any variables named in 1045.Ql Va MAKE_PRINT_VAR_ON_ERROR . 1046.It Va .newline 1047This variable is simply assigned a newline character as its value. 1048This allows expansions using the 1049.Cm \&:@ 1050modifier to put a newline between 1051iterations of the loop rather than a space. 1052For example, the printing of 1053.Ql Va MAKE_PRINT_VAR_ON_ERROR 1054could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}. 1055.It Va .OBJDIR 1056A path to the directory where the targets are built. 1057Its value is determined by trying to 1058.Xr chdir 2 1059to the following directories in order and using the first match: 1060.Bl -enum 1061.It 1062.Ev ${MAKEOBJDIRPREFIX}${.CURDIR} 1063.Pp 1064(Only if 1065.Ql Ev MAKEOBJDIRPREFIX 1066is set in the environment or on the command line.) 1067.It 1068.Ev ${MAKEOBJDIR} 1069.Pp 1070(Only if 1071.Ql Ev MAKEOBJDIR 1072is set in the environment or on the command line.) 1073.It 1074.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE} 1075.It 1076.Ev ${.CURDIR} Ns Pa /obj 1077.It 1078.Pa /usr/obj/ Ns Ev ${.CURDIR} 1079.It 1080.Ev ${.CURDIR} 1081.El 1082.Pp 1083Variable expansion is performed on the value before it's used, 1084so expressions such as 1085.Dl ${.CURDIR:S,^/usr/src,/var/obj,} 1086may be used. 1087This is especially useful with 1088.Ql Ev MAKEOBJDIR . 1089.Pp 1090.Ql Va .OBJDIR 1091may be modified in the makefile via the special target 1092.Ql Ic .OBJDIR . 1093In all cases, 1094.Nm 1095will 1096.Xr chdir 2 1097to the specified directory if it exists, and set 1098.Ql Va .OBJDIR 1099and 1100.Ql Ev PWD 1101to that directory before executing any targets. 1102.Pp 1103Except in the case of an explicit 1104.Ql Ic .OBJDIR 1105target, 1106.Nm 1107will check that the specified directory is writable and ignore it if not. 1108This check can be skipped by setting the environment variable 1109.Ql Ev MAKE_OBJDIR_CHECK_WRITABLE 1110to "no". 1111. 1112.It Va .PARSEDIR 1113A path to the directory of the current 1114.Ql Pa Makefile 1115being parsed. 1116.It Va .PARSEFILE 1117The basename of the current 1118.Ql Pa Makefile 1119being parsed. 1120This variable and 1121.Ql Va .PARSEDIR 1122are both set only while the 1123.Ql Pa Makefiles 1124are being parsed. 1125If you want to retain their current values, assign them to a variable 1126using assignment with expansion: 1127.Pq Ql Cm \&:= . 1128.It Va .PATH 1129A variable that represents the list of directories that 1130.Nm 1131will search for files. 1132The search list should be updated using the target 1133.Ql Va .PATH 1134rather than the variable. 1135.It Ev PWD 1136Alternate path to the current directory. 1137.Nm 1138normally sets 1139.Ql Va .CURDIR 1140to the canonical path given by 1141.Xr getcwd 3 . 1142However, if the environment variable 1143.Ql Ev PWD 1144is set and gives a path to the current directory, then 1145.Nm 1146sets 1147.Ql Va .CURDIR 1148to the value of 1149.Ql Ev PWD 1150instead. 1151This behavior is disabled if 1152.Ql Ev MAKEOBJDIRPREFIX 1153is set or 1154.Ql Ev MAKEOBJDIR 1155contains a variable transform. 1156.Ql Ev PWD 1157is set to the value of 1158.Ql Va .OBJDIR 1159for all programs which 1160.Nm 1161executes. 1162.It Ev .SHELL 1163The pathname of the shell used to run target scripts. 1164It is read-only. 1165.It Ev .TARGETS 1166The list of targets explicitly specified on the command line, if any. 1167.It Ev VPATH 1168Colon-separated 1169.Pq Dq \&: 1170lists of directories that 1171.Nm 1172will search for files. 1173The variable is supported for compatibility with old make programs only, 1174use 1175.Ql Va .PATH 1176instead. 1177.El 1178.Ss Variable modifiers 1179Variable expansion may be modified to select or modify each word of the 1180variable (where a 1181.Dq word 1182is white-space delimited sequence of characters). 1183The general format of a variable expansion is as follows: 1184.Pp 1185.Dl ${variable[:modifier[:...]]} 1186.Pp 1187Each modifier begins with a colon, 1188which may be escaped with a backslash 1189.Pq Ql \e . 1190.Pp 1191A set of modifiers can be specified via a variable, as follows: 1192.Pp 1193.Dl modifier_variable=modifier[:...] 1194.Dl ${variable:${modifier_variable}[:...]} 1195.Pp 1196In this case the first modifier in the modifier_variable does not 1197start with a colon, since that must appear in the referencing 1198variable. 1199If any of the modifiers in the modifier_variable contain a dollar sign 1200.Pq Ql $ , 1201these must be doubled to avoid early expansion. 1202.Pp 1203The supported modifiers are: 1204.Bl -tag -width EEE 1205.It Cm \&:E 1206Replaces each word in the variable with its suffix. 1207.It Cm \&:H 1208Replaces each word in the variable with everything but the last component. 1209.It Cm \&:M Ns Ar pattern 1210Selects only those words that match 1211.Ar pattern . 1212The standard shell wildcard characters 1213.Pf ( Ql * , 1214.Ql \&? , 1215and 1216.Ql Oo Oc ) 1217may 1218be used. 1219The wildcard characters may be escaped with a backslash 1220.Pq Ql \e . 1221As a consequence of the way values are split into words, matched, 1222and then joined, a construct like 1223.Dl ${VAR:M*} 1224will normalize the inter-word spacing, removing all leading and 1225trailing space, and converting multiple consecutive spaces 1226to single spaces. 1227. 1228.It Cm \&:N Ns Ar pattern 1229This is identical to 1230.Ql Cm \&:M , 1231but selects all words which do not match 1232.Ar pattern . 1233.It Cm \&:O 1234Orders every word in variable alphabetically. 1235.It Cm \&:Or 1236Orders every word in variable in reverse alphabetical order. 1237.It Cm \&:Ox 1238Shuffles the words in variable. 1239The results will be different each time you are referring to the 1240modified variable; use the assignment with expansion 1241.Pq Ql Cm \&:= 1242to prevent such behavior. 1243For example, 1244.Bd -literal -offset indent 1245LIST= uno due tre quattro 1246RANDOM_LIST= ${LIST:Ox} 1247STATIC_RANDOM_LIST:= ${LIST:Ox} 1248 1249all: 1250 @echo "${RANDOM_LIST}" 1251 @echo "${RANDOM_LIST}" 1252 @echo "${STATIC_RANDOM_LIST}" 1253 @echo "${STATIC_RANDOM_LIST}" 1254.Ed 1255may produce output similar to: 1256.Bd -literal -offset indent 1257quattro due tre uno 1258tre due quattro uno 1259due uno quattro tre 1260due uno quattro tre 1261.Ed 1262.It Cm \&:Q 1263Quotes every shell meta-character in the variable, so that it can be passed 1264safely to the shell. 1265.It Cm \&:q 1266Quotes every shell meta-character in the variable, and also doubles 1267.Sq $ 1268characters so that it can be passed 1269safely through recursive invocations of 1270.Nm . 1271This is equivalent to: 1272.Sq \&:S/\e\&$/&&/g:Q . 1273.It Cm \&:R 1274Replaces each word in the variable with everything but its suffix. 1275.It Cm \&:range[=count] 1276The value is an integer sequence representing the words of the original 1277value, or the supplied 1278.Va count . 1279.It Cm \&:gmtime[=utc] 1280The value is a format string for 1281.Xr strftime 3 , 1282using 1283.Xr gmtime 3 . 1284If a 1285.Va utc 1286value is not provided or is 0, the current time is used. 1287.It Cm \&:hash 1288Computes a 32-bit hash of the value and encode it as hex digits. 1289.It Cm \&:localtime[=utc] 1290The value is a format string for 1291.Xr strftime 3 , 1292using 1293.Xr localtime 3 . 1294If a 1295.Va utc 1296value is not provided or is 0, the current time is used. 1297.It Cm \&:tA 1298Attempts to convert variable to an absolute path using 1299.Xr realpath 3 , 1300if that fails, the value is unchanged. 1301.It Cm \&:tl 1302Converts variable to lower-case letters. 1303.It Cm \&:ts Ns Ar c 1304Words in the variable are normally separated by a space on expansion. 1305This modifier sets the separator to the character 1306.Ar c . 1307If 1308.Ar c 1309is omitted, then no separator is used. 1310The common escapes (including octal numeric codes) work as expected. 1311.It Cm \&:tu 1312Converts variable to upper-case letters. 1313.It Cm \&:tW 1314Causes the value to be treated as a single word 1315(possibly containing embedded white space). 1316See also 1317.Ql Cm \&:[*] . 1318.It Cm \&:tw 1319Causes the value to be treated as a sequence of 1320words delimited by white space. 1321See also 1322.Ql Cm \&:[@] . 1323.Sm off 1324.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW 1325.Sm on 1326Modifies the first occurrence of 1327.Ar old_string 1328in each word of the variable's value, replacing it with 1329.Ar new_string . 1330If a 1331.Ql g 1332is appended to the last delimiter of the pattern, all occurrences 1333in each word are replaced. 1334If a 1335.Ql 1 1336is appended to the last delimiter of the pattern, only the first occurrence 1337is affected. 1338If a 1339.Ql W 1340is appended to the last delimiter of the pattern, 1341then the value is treated as a single word 1342(possibly containing embedded white space). 1343If 1344.Ar old_string 1345begins with a caret 1346.Pq Ql ^ , 1347.Ar old_string 1348is anchored at the beginning of each word. 1349If 1350.Ar old_string 1351ends with a dollar sign 1352.Pq Ql \&$ , 1353it is anchored at the end of each word. 1354Inside 1355.Ar new_string , 1356an ampersand 1357.Pq Ql & 1358is replaced by 1359.Ar old_string 1360(without any 1361.Ql ^ 1362or 1363.Ql \&$ ) . 1364Any character may be used as a delimiter for the parts of the modifier 1365string. 1366The anchoring, ampersand and delimiter characters may be escaped with a 1367backslash 1368.Pq Ql \e . 1369.Pp 1370Variable expansion occurs in the normal fashion inside both 1371.Ar old_string 1372and 1373.Ar new_string 1374with the single exception that a backslash is used to prevent the expansion 1375of a dollar sign 1376.Pq Ql \&$ , 1377not a preceding dollar sign as is usual. 1378.Sm off 1379.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW 1380.Sm on 1381The 1382.Cm \&:C 1383modifier is just like the 1384.Cm \&:S 1385modifier except that the old and new strings, instead of being 1386simple strings, are an extended regular expression (see 1387.Xr regex 3 ) 1388string 1389.Ar pattern 1390and an 1391.Xr ed 1 Ns \-style 1392string 1393.Ar replacement . 1394Normally, the first occurrence of the pattern 1395.Ar pattern 1396in each word of the value is substituted with 1397.Ar replacement . 1398The 1399.Ql 1 1400modifier causes the substitution to apply to at most one word; the 1401.Ql g 1402modifier causes the substitution to apply to as many instances of the 1403search pattern 1404.Ar pattern 1405as occur in the word or words it is found in; the 1406.Ql W 1407modifier causes the value to be treated as a single word 1408(possibly containing embedded white space). 1409.Pp 1410As for the 1411.Cm \&:S 1412modifier, the 1413.Ar pattern 1414and 1415.Ar replacement 1416are subjected to variable expansion before being parsed as 1417regular expressions. 1418.It Cm \&:T 1419Replaces each word in the variable with its last path component. 1420.It Cm \&:u 1421Removes adjacent duplicate words (like 1422.Xr uniq 1 ) . 1423.Sm off 1424.It Cm \&:\&? Ar true_string Cm \&: Ar false_string 1425.Sm on 1426If the variable name (not its value), when parsed as a .if conditional 1427expression, evaluates to true, return as its value the 1428.Ar true_string , 1429otherwise return the 1430.Ar false_string . 1431Since the variable name is used as the expression, \&:\&? must be the 1432first modifier after the variable name itself - which will, of course, 1433usually contain variable expansions. 1434A common error is trying to use expressions like 1435.Dl ${NUMBERS:M42:?match:no} 1436which actually tests defined(NUMBERS), 1437to determine if any words match "42" you need to use something like: 1438.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} . 1439.It Ar :old_string=new_string 1440This is the 1441.At V 1442style variable substitution. 1443It must be the last modifier specified. 1444If 1445.Ar old_string 1446or 1447.Ar new_string 1448do not contain the pattern matching character 1449.Ar % 1450then it is assumed that they are 1451anchored at the end of each word, so only suffixes or entire 1452words may be replaced. 1453Otherwise 1454.Ar % 1455is the substring of 1456.Ar old_string 1457to be replaced in 1458.Ar new_string . 1459If only 1460.Ar old_string 1461contains the pattern matching character 1462.Ar % , 1463and 1464.Ar old_string 1465matches, then the result is the 1466.Ar new_string . 1467If only the 1468.Ar new_string 1469contains the pattern matching character 1470.Ar % , 1471then it is not treated specially and it is printed as a literal 1472.Ar % 1473on match. 1474If there is more than one pattern matching character 1475.Ar ( % ) 1476in either the 1477.Ar new_string 1478or 1479.Ar old_string , 1480only the first instance is treated specially (as the pattern character); 1481all subsequent instances are treated as regular characters. 1482.Pp 1483Variable expansion occurs in the normal fashion inside both 1484.Ar old_string 1485and 1486.Ar new_string 1487with the single exception that a backslash is used to prevent the 1488expansion of a dollar sign 1489.Pq Ql \&$ , 1490not a preceding dollar sign as is usual. 1491.Sm off 1492.It Cm \&:@ Ar temp Cm @ Ar string Cm @ 1493.Sm on 1494This is the loop expansion mechanism from the OSF Development 1495Environment (ODE) make. 1496Unlike 1497.Cm \&.for 1498loops, expansion occurs at the time of reference. 1499Assigns 1500.Ar temp 1501to each word in the variable and evaluates 1502.Ar string . 1503The ODE convention is that 1504.Ar temp 1505should start and end with a period. 1506For example. 1507.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@} 1508.Pp 1509However a single character variable is often more readable: 1510.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@} 1511.It Cm \&:_[=var] 1512Saves the current variable value in 1513.Ql $_ 1514or the named 1515.Va var 1516for later reference. 1517Example usage: 1518.Bd -literal -offset indent 1519M_cmpv.units = 1 1000 1000000 1520M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\ 1521\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh 1522 1523.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}} 1524 1525.Ed 1526Here 1527.Ql $_ 1528is used to save the result of the 1529.Ql :S 1530modifier which is later referenced using the index values from 1531.Ql :range . 1532.It Cm \&:U Ns Ar newval 1533If the variable is undefined, 1534.Ar newval 1535is the value. 1536If the variable is defined, the existing value is returned. 1537This is another ODE make feature. 1538It is handy for setting per-target CFLAGS for instance: 1539.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}} 1540If a value is only required if the variable is undefined, use: 1541.Dl ${VAR:D:Unewval} 1542.It Cm \&:D Ns Ar newval 1543If the variable is defined, 1544.Ar newval 1545is the value. 1546.It Cm \&:L 1547The name of the variable is the value. 1548.It Cm \&:P 1549The path of the node which has the same name as the variable 1550is the value. 1551If no such node exists or its path is null, then the 1552name of the variable is used. 1553In order for this modifier to work, the name (node) must at least have 1554appeared on the rhs of a dependency. 1555.Sm off 1556.It Cm \&:\&! Ar cmd Cm \&! 1557.Sm on 1558The output of running 1559.Ar cmd 1560is the value. 1561.It Cm \&:sh 1562If the variable is non-empty it is run as a command and the output 1563becomes the new value. 1564.It Cm \&::= Ns Ar str 1565The variable is assigned the value 1566.Ar str 1567after substitution. 1568This modifier and its variations are useful in 1569obscure situations such as wanting to set a variable when shell commands 1570are being parsed. 1571These assignment modifiers always expand to 1572nothing, so if appearing in a rule line by themselves should be 1573preceded with something to keep 1574.Nm 1575happy. 1576.Pp 1577The 1578.Ql Cm \&:: 1579helps avoid false matches with the 1580.At V 1581style 1582.Cm \&:= 1583modifier and since substitution always occurs the 1584.Cm \&::= 1585form is vaguely appropriate. 1586.It Cm \&::?= Ns Ar str 1587As for 1588.Cm \&::= 1589but only if the variable does not already have a value. 1590.It Cm \&::+= Ns Ar str 1591Append 1592.Ar str 1593to the variable. 1594.It Cm \&::!= Ns Ar cmd 1595Assign the output of 1596.Ar cmd 1597to the variable. 1598.It Cm \&:\&[ Ns Ar range Ns Cm \&] 1599Selects one or more words from the value, 1600or performs other operations related to the way in which the 1601value is divided into words. 1602.Pp 1603Ordinarily, a value is treated as a sequence of words 1604delimited by white space. 1605Some modifiers suppress this behavior, 1606causing a value to be treated as a single word 1607(possibly containing embedded white space). 1608An empty value, or a value that consists entirely of white-space, 1609is treated as a single word. 1610For the purposes of the 1611.Ql Cm \&:[] 1612modifier, the words are indexed both forwards using positive integers 1613(where index 1 represents the first word), 1614and backwards using negative integers 1615(where index \-1 represents the last word). 1616.Pp 1617The 1618.Ar range 1619is subjected to variable expansion, and the expanded result is 1620then interpreted as follows: 1621.Bl -tag -width index 1622.\" :[n] 1623.It Ar index 1624Selects a single word from the value. 1625.\" :[start..end] 1626.It Ar start Ns Cm \&.. Ns Ar end 1627Selects all words from 1628.Ar start 1629to 1630.Ar end , 1631inclusive. 1632For example, 1633.Ql Cm \&:[2..-1] 1634selects all words from the second word to the last word. 1635If 1636.Ar start 1637is greater than 1638.Ar end , 1639then the words are output in reverse order. 1640For example, 1641.Ql Cm \&:[-1..1] 1642selects all the words from last to first. 1643If the list is already ordered, then this effectively reverses 1644the list, but it is more efficient to use 1645.Ql Cm \&:Or 1646instead of 1647.Ql Cm \&:O:[-1..1] . 1648.\" :[*] 1649.It Cm \&* 1650Causes subsequent modifiers to treat the value as a single word 1651(possibly containing embedded white space). 1652Analogous to the effect of 1653\&"$*\&" 1654in Bourne shell. 1655.\" :[0] 1656.It 0 1657Means the same as 1658.Ql Cm \&:[*] . 1659.\" :[*] 1660.It Cm \&@ 1661Causes subsequent modifiers to treat the value as a sequence of words 1662delimited by white space. 1663Analogous to the effect of 1664\&"$@\&" 1665in Bourne shell. 1666.\" :[#] 1667.It Cm \&# 1668Returns the number of words in the value. 1669.El \" :[range] 1670.El 1671.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS 1672Makefile inclusion, conditional structures and for loops reminiscent 1673of the C programming language are provided in 1674.Nm . 1675All such structures are identified by a line beginning with a single 1676dot 1677.Pq Ql \&. 1678character. 1679Files are included with either 1680.Cm \&.include \&< Ns Ar file Ns Cm \&> 1681or 1682.Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q . 1683Variables between the angle brackets or double quotes are expanded 1684to form the file name. 1685If angle brackets are used, the included makefile is expected to be in 1686the system makefile directory. 1687If double quotes are used, the including makefile's directory and any 1688directories specified using the 1689.Fl I 1690option are searched before the system 1691makefile directory. 1692For compatibility with other versions of 1693.Nm 1694.Ql include file ... 1695is also accepted. 1696.Pp 1697If the include statement is written as 1698.Cm .-include 1699or as 1700.Cm .sinclude 1701then errors locating and/or opening include files are ignored. 1702.Pp 1703If the include statement is written as 1704.Cm .dinclude 1705not only are errors locating and/or opening include files ignored, 1706but stale dependencies within the included file will be ignored 1707just like 1708.Va .MAKE.DEPENDFILE . 1709.Pp 1710Conditional expressions are also preceded by a single dot as the first 1711character of a line. 1712The possible conditionals are as follows: 1713.Bl -tag -width Ds 1714.It Ic .error Ar message 1715The message is printed along with the name of the makefile and line number, 1716then 1717.Nm 1718will exit immediately. 1719.It Ic .export Ar variable ... 1720Export the specified global variable. 1721If no variable list is provided, all globals are exported 1722except for internal variables (those that start with 1723.Ql \&. ) . 1724This is not affected by the 1725.Fl X 1726flag, so should be used with caution. 1727For compatibility with other 1728.Nm 1729programs 1730.Ql export variable=value 1731is also accepted. 1732.Pp 1733Appending a variable name to 1734.Va .MAKE.EXPORTED 1735is equivalent to exporting a variable. 1736.It Ic .export-env Ar variable ... 1737The same as 1738.Ql .export , 1739except that the variable is not appended to 1740.Va .MAKE.EXPORTED . 1741This allows exporting a value to the environment which is different from that 1742used by 1743.Nm 1744internally. 1745.It Ic .export-literal Ar variable ... 1746The same as 1747.Ql .export-env , 1748except that variables in the value are not expanded. 1749.It Ic .info Ar message 1750The message is printed along with the name of the makefile and line number. 1751.It Ic .undef Ar variable ... 1752Un-define the specified global variables. 1753Only global variables can be un-defined. 1754.It Ic .unexport Ar variable ... 1755The opposite of 1756.Ql .export . 1757The specified global 1758.Va variable 1759will be removed from 1760.Va .MAKE.EXPORTED . 1761If no variable list is provided, all globals are unexported, 1762and 1763.Va .MAKE.EXPORTED 1764deleted. 1765.It Ic .unexport-env 1766Unexport all globals previously exported and 1767clear the environment inherited from the parent. 1768This operation will cause a memory leak of the original environment, 1769so should be used sparingly. 1770Testing for 1771.Va .MAKE.LEVEL 1772being 0, would make sense. 1773Also note that any variables which originated in the parent environment 1774should be explicitly preserved if desired. 1775For example: 1776.Bd -literal -offset indent 1777.Li .if ${.MAKE.LEVEL} == 0 1778PATH := ${PATH} 1779.Li .unexport-env 1780.Li .export PATH 1781.Li .endif 1782.Pp 1783.Ed 1784Would result in an environment containing only 1785.Ql Ev PATH , 1786which is the minimal useful environment. 1787Actually 1788.Ql Ev .MAKE.LEVEL 1789will also be pushed into the new environment. 1790.It Ic .warning Ar message 1791The message prefixed by 1792.Ql Pa warning: 1793is printed along with the name of the makefile and line number. 1794.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ... 1795Test the value of an expression. 1796.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1797Test the value of a variable. 1798.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1799Test the value of a variable. 1800.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1801Test the target being built. 1802.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ... 1803Test the target being built. 1804.It Ic .else 1805Reverse the sense of the last conditional. 1806.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ... 1807A combination of 1808.Ql Ic .else 1809followed by 1810.Ql Ic .if . 1811.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1812A combination of 1813.Ql Ic .else 1814followed by 1815.Ql Ic .ifdef . 1816.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ... 1817A combination of 1818.Ql Ic .else 1819followed by 1820.Ql Ic .ifndef . 1821.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1822A combination of 1823.Ql Ic .else 1824followed by 1825.Ql Ic .ifmake . 1826.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ... 1827A combination of 1828.Ql Ic .else 1829followed by 1830.Ql Ic .ifnmake . 1831.It Ic .endif 1832End the body of the conditional. 1833.El 1834.Pp 1835The 1836.Ar operator 1837may be any one of the following: 1838.Bl -tag -width "Cm XX" 1839.It Cm \&|\&| 1840Logical OR. 1841.It Cm \&&& 1842Logical 1843.Tn AND ; 1844of higher precedence than 1845.Dq \&|\&| . 1846.El 1847.Pp 1848As in C, 1849.Nm 1850will only evaluate a conditional as far as is necessary to determine 1851its value. 1852Parentheses may be used to change the order of evaluation. 1853The boolean operator 1854.Ql Ic \&! 1855may be used to logically negate an entire 1856conditional. 1857It is of higher precedence than 1858.Ql Ic \&&& . 1859.Pp 1860The value of 1861.Ar expression 1862may be any of the following: 1863.Bl -tag -width defined 1864.It Ic defined 1865Takes a variable name as an argument and evaluates to true if the variable 1866has been defined. 1867.It Ic make 1868Takes a target name as an argument and evaluates to true if the target 1869was specified as part of 1870.Nm Ns 's 1871command line or was declared the default target (either implicitly or 1872explicitly, see 1873.Va .MAIN ) 1874before the line containing the conditional. 1875.It Ic empty 1876Takes a variable, with possible modifiers, and evaluates to true if 1877the expansion of the variable would result in an empty string. 1878.It Ic exists 1879Takes a file name as an argument and evaluates to true if the file exists. 1880The file is searched for on the system search path (see 1881.Va .PATH ) . 1882.It Ic target 1883Takes a target name as an argument and evaluates to true if the target 1884has been defined. 1885.It Ic commands 1886Takes a target name as an argument and evaluates to true if the target 1887has been defined and has commands associated with it. 1888.El 1889.Pp 1890.Ar Expression 1891may also be an arithmetic or string comparison. 1892Variable expansion is 1893performed on both sides of the comparison, after which the numerical 1894values are compared. 1895A value is interpreted as hexadecimal if it is 1896preceded by 0x, otherwise it is decimal; octal numbers are not supported. 1897The standard C relational operators are all supported. 1898If after 1899variable expansion, either the left or right hand side of a 1900.Ql Ic == 1901or 1902.Ql Ic "!=" 1903operator is not a numerical value, then 1904string comparison is performed between the expanded 1905variables. 1906If no relational operator is given, it is assumed that the expanded 1907variable is being compared against 0, or an empty string in the case 1908of a string comparison. 1909.Pp 1910When 1911.Nm 1912is evaluating one of these conditional expressions, and it encounters 1913a (white-space separated) word it doesn't recognize, either the 1914.Dq make 1915or 1916.Dq defined 1917expression is applied to it, depending on the form of the conditional. 1918If the form is 1919.Ql Ic .ifdef , 1920.Ql Ic .ifndef , 1921or 1922.Ql Ic .if 1923the 1924.Dq defined 1925expression is applied. 1926Similarly, if the form is 1927.Ql Ic .ifmake 1928or 1929.Ql Ic .ifnmake , 1930the 1931.Dq make 1932expression is applied. 1933.Pp 1934If the conditional evaluates to true the parsing of the makefile continues 1935as before. 1936If it evaluates to false, the following lines are skipped. 1937In both cases this continues until a 1938.Ql Ic .else 1939or 1940.Ql Ic .endif 1941is found. 1942.Pp 1943For loops are typically used to apply a set of rules to a list of files. 1944The syntax of a for loop is: 1945.Pp 1946.Bl -tag -compact -width Ds 1947.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression 1948.It Aq make-lines 1949.It Ic \&.endfor 1950.El 1951.Pp 1952After the for 1953.Ic expression 1954is evaluated, it is split into words. 1955On each iteration of the loop, one word is taken and assigned to each 1956.Ic variable , 1957in order, and these 1958.Ic variables 1959are substituted into the 1960.Ic make-lines 1961inside the body of the for loop. 1962The number of words must come out even; that is, if there are three 1963iteration variables, the number of words provided must be a multiple 1964of three. 1965.Sh COMMENTS 1966Comments begin with a hash 1967.Pq Ql \&# 1968character, anywhere but in a shell 1969command line, and continue to the end of an unescaped new line. 1970.Sh SPECIAL SOURCES (ATTRIBUTES) 1971.Bl -tag -width .IGNOREx 1972.It Ic .EXEC 1973Target is never out of date, but always execute commands anyway. 1974.It Ic .IGNORE 1975Ignore any errors from the commands associated with this target, exactly 1976as if they all were preceded by a dash 1977.Pq Ql \- . 1978.\" .It Ic .INVISIBLE 1979.\" XXX 1980.\" .It Ic .JOIN 1981.\" XXX 1982.It Ic .MADE 1983Mark all sources of this target as being up-to-date. 1984.It Ic .MAKE 1985Execute the commands associated with this target even if the 1986.Fl n 1987or 1988.Fl t 1989options were specified. 1990Normally used to mark recursive 1991.Nm Ns s . 1992.It Ic .META 1993Create a meta file for the target, even if it is flagged as 1994.Ic .PHONY , 1995.Ic .MAKE , 1996or 1997.Ic .SPECIAL . 1998Usage in conjunction with 1999.Ic .MAKE 2000is the most likely case. 2001In "meta" mode, the target is out-of-date if the meta file is missing. 2002.It Ic .NOMETA 2003Do not create a meta file for the target. 2004Meta files are also not created for 2005.Ic .PHONY , 2006.Ic .MAKE , 2007or 2008.Ic .SPECIAL 2009targets. 2010.It Ic .NOMETA_CMP 2011Ignore differences in commands when deciding if target is out of date. 2012This is useful if the command contains a value which always changes. 2013If the number of commands change, though, the target will still be out of date. 2014The same effect applies to any command line that uses the variable 2015.Va .OODATE , 2016which can be used for that purpose even when not otherwise needed or desired: 2017.Bd -literal -offset indent 2018 2019skip-compare-for-some: 2020 @echo this will be compared 2021 @echo this will not ${.OODATE:M.NOMETA_CMP} 2022 @echo this will also be compared 2023 2024.Ed 2025The 2026.Cm \&:M 2027pattern suppresses any expansion of the unwanted variable. 2028.It Ic .NOPATH 2029Do not search for the target in the directories specified by 2030.Ic .PATH . 2031.It Ic .NOTMAIN 2032Normally 2033.Nm 2034selects the first target it encounters as the default target to be built 2035if no target was specified. 2036This source prevents this target from being selected. 2037.It Ic .OPTIONAL 2038If a target is marked with this attribute and 2039.Nm 2040can't figure out how to create it, it will ignore this fact and assume 2041the file isn't needed or already exists. 2042.It Ic .PHONY 2043The target does not 2044correspond to an actual file; it is always considered to be out of date, 2045and will not be created with the 2046.Fl t 2047option. 2048Suffix-transformation rules are not applied to 2049.Ic .PHONY 2050targets. 2051.It Ic .PRECIOUS 2052When 2053.Nm 2054is interrupted, it normally removes any partially made targets. 2055This source prevents the target from being removed. 2056.It Ic .RECURSIVE 2057Synonym for 2058.Ic .MAKE . 2059.It Ic .SILENT 2060Do not echo any of the commands associated with this target, exactly 2061as if they all were preceded by an at sign 2062.Pq Ql @ . 2063.It Ic .USE 2064Turn the target into 2065.Nm Ns 's 2066version of a macro. 2067When the target is used as a source for another target, the other target 2068acquires the commands, sources, and attributes (except for 2069.Ic .USE ) 2070of the 2071source. 2072If the target already has commands, the 2073.Ic .USE 2074target's commands are appended 2075to them. 2076.It Ic .USEBEFORE 2077Exactly like 2078.Ic .USE , 2079but prepend the 2080.Ic .USEBEFORE 2081target commands to the target. 2082.It Ic .WAIT 2083If 2084.Ic .WAIT 2085appears in a dependency line, the sources that precede it are 2086made before the sources that succeed it in the line. 2087Since the dependents of files are not made until the file itself 2088could be made, this also stops the dependents being built unless they 2089are needed for another branch of the dependency tree. 2090So given: 2091.Bd -literal 2092x: a .WAIT b 2093 echo x 2094a: 2095 echo a 2096b: b1 2097 echo b 2098b1: 2099 echo b1 2100 2101.Ed 2102the output is always 2103.Ql a , 2104.Ql b1 , 2105.Ql b , 2106.Ql x . 2107.br 2108The ordering imposed by 2109.Ic .WAIT 2110is only relevant for parallel makes. 2111.El 2112.Sh SPECIAL TARGETS 2113Special targets may not be included with other targets, i.e. they must be 2114the only target specified. 2115.Bl -tag -width .BEGINx 2116.It Ic .BEGIN 2117Any command lines attached to this target are executed before anything 2118else is done. 2119.It Ic .DEFAULT 2120This is sort of a 2121.Ic .USE 2122rule for any target (that was used only as a 2123source) that 2124.Nm 2125can't figure out any other way to create. 2126Only the shell script is used. 2127The 2128.Ic .IMPSRC 2129variable of a target that inherits 2130.Ic .DEFAULT Ns 's 2131commands is set 2132to the target's own name. 2133.It Ic .DELETE_ON_ERROR 2134If this target is present in the makefile, it globally causes make to 2135delete targets whose commands fail. 2136(By default, only targets whose commands are interrupted during 2137execution are deleted. 2138This is the historical behavior.) 2139This setting can be used to help prevent half-finished or malformed 2140targets from being left around and corrupting future rebuilds. 2141.It Ic .END 2142Any command lines attached to this target are executed after everything 2143else is done. 2144.It Ic .ERROR 2145Any command lines attached to this target are executed when another target fails. 2146The 2147.Ic .ERROR_TARGET 2148variable is set to the target that failed. 2149See also 2150.Ic MAKE_PRINT_VAR_ON_ERROR . 2151.It Ic .IGNORE 2152Mark each of the sources with the 2153.Ic .IGNORE 2154attribute. 2155If no sources are specified, this is the equivalent of specifying the 2156.Fl i 2157option. 2158.It Ic .INTERRUPT 2159If 2160.Nm 2161is interrupted, the commands for this target will be executed. 2162.It Ic .MAIN 2163If no target is specified when 2164.Nm 2165is invoked, this target will be built. 2166.It Ic .MAKEFLAGS 2167This target provides a way to specify flags for 2168.Nm 2169when the makefile is used. 2170The flags are as if typed to the shell, though the 2171.Fl f 2172option will have 2173no effect. 2174.\" XXX: NOT YET!!!! 2175.\" .It Ic .NOTPARALLEL 2176.\" The named targets are executed in non parallel mode. 2177.\" If no targets are 2178.\" specified, then all targets are executed in non parallel mode. 2179.It Ic .NOPATH 2180Apply the 2181.Ic .NOPATH 2182attribute to any specified sources. 2183.It Ic .NOTPARALLEL 2184Disable parallel mode. 2185.It Ic .NO_PARALLEL 2186Synonym for 2187.Ic .NOTPARALLEL , 2188for compatibility with other pmake variants. 2189.It Ic .OBJDIR 2190The source is a new value for 2191.Ql Va .OBJDIR . 2192If it exists, 2193.Nm 2194will 2195.Xr chdir 2 2196to it and update the value of 2197.Ql Va .OBJDIR . 2198.It Ic .ORDER 2199The named targets are made in sequence. 2200This ordering does not add targets to the list of targets to be made. 2201Since the dependents of a target do not get built until the target itself 2202could be built, unless 2203.Ql a 2204is built by another part of the dependency graph, 2205the following is a dependency loop: 2206.Bd -literal 2207\&.ORDER: b a 2208b: a 2209.Ed 2210.Pp 2211The ordering imposed by 2212.Ic .ORDER 2213is only relevant for parallel makes. 2214.\" XXX: NOT YET!!!! 2215.\" .It Ic .PARALLEL 2216.\" The named targets are executed in parallel mode. 2217.\" If no targets are 2218.\" specified, then all targets are executed in parallel mode. 2219.It Ic .PATH 2220The sources are directories which are to be searched for files not 2221found in the current directory. 2222If no sources are specified, any previously specified directories are 2223deleted. 2224If the source is the special 2225.Ic .DOTLAST 2226target, then the current working 2227directory is searched last. 2228.It Ic .PATH. Ns Va suffix 2229Like 2230.Ic .PATH 2231but applies only to files with a particular suffix. 2232The suffix must have been previously declared with 2233.Ic .SUFFIXES . 2234.It Ic .PHONY 2235Apply the 2236.Ic .PHONY 2237attribute to any specified sources. 2238.It Ic .PRECIOUS 2239Apply the 2240.Ic .PRECIOUS 2241attribute to any specified sources. 2242If no sources are specified, the 2243.Ic .PRECIOUS 2244attribute is applied to every 2245target in the file. 2246.It Ic .SHELL 2247Sets the shell that 2248.Nm 2249will use to execute commands. 2250The sources are a set of 2251.Ar field=value 2252pairs. 2253.Bl -tag -width hasErrCtls 2254.It Ar name 2255This is the minimal specification, used to select one of the built-in 2256shell specs; 2257.Ar sh , 2258.Ar ksh , 2259and 2260.Ar csh . 2261.It Ar path 2262Specifies the path to the shell. 2263.It Ar hasErrCtl 2264Indicates whether the shell supports exit on error. 2265.It Ar check 2266The command to turn on error checking. 2267.It Ar ignore 2268The command to disable error checking. 2269.It Ar echo 2270The command to turn on echoing of commands executed. 2271.It Ar quiet 2272The command to turn off echoing of commands executed. 2273.It Ar filter 2274The output to filter after issuing the 2275.Ar quiet 2276command. 2277It is typically identical to 2278.Ar quiet . 2279.It Ar errFlag 2280The flag to pass the shell to enable error checking. 2281.It Ar echoFlag 2282The flag to pass the shell to enable command echoing. 2283.It Ar newline 2284The string literal to pass the shell that results in a single newline 2285character when used outside of any quoting characters. 2286.El 2287Example: 2288.Bd -literal 2289\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e 2290 check="set \-e" ignore="set +e" \e 2291 echo="set \-v" quiet="set +v" filter="set +v" \e 2292 echoFlag=v errFlag=e newline="'\en'" 2293.Ed 2294.It Ic .SILENT 2295Apply the 2296.Ic .SILENT 2297attribute to any specified sources. 2298If no sources are specified, the 2299.Ic .SILENT 2300attribute is applied to every 2301command in the file. 2302.It Ic .STALE 2303This target gets run when a dependency file contains stale entries, having 2304.Va .ALLSRC 2305set to the name of that dependency file. 2306.It Ic .SUFFIXES 2307Each source specifies a suffix to 2308.Nm . 2309If no sources are specified, any previously specified suffixes are deleted. 2310It allows the creation of suffix-transformation rules. 2311.Pp 2312Example: 2313.Bd -literal 2314\&.SUFFIXES: .o 2315\&.c.o: 2316 cc \-o ${.TARGET} \-c ${.IMPSRC} 2317.Ed 2318.El 2319.Sh ENVIRONMENT 2320.Nm 2321uses the following environment variables, if they exist: 2322.Ev MACHINE , 2323.Ev MACHINE_ARCH , 2324.Ev MAKE , 2325.Ev MAKEFLAGS , 2326.Ev MAKEOBJDIR , 2327.Ev MAKEOBJDIRPREFIX , 2328.Ev MAKESYSPATH , 2329.Ev PWD , 2330and 2331.Ev TMPDIR . 2332.Pp 2333.Ev MAKEOBJDIRPREFIX 2334and 2335.Ev MAKEOBJDIR 2336may only be set in the environment or on the command line to 2337.Nm 2338and not as makefile variables; 2339see the description of 2340.Ql Va .OBJDIR 2341for more details. 2342.Sh FILES 2343.Bl -tag -width /usr/share/mk -compact 2344.It .depend 2345list of dependencies 2346.It Makefile 2347list of dependencies 2348.It makefile 2349list of dependencies 2350.It sys.mk 2351system makefile 2352.It /usr/share/mk 2353system makefile directory 2354.El 2355.Sh COMPATIBILITY 2356The basic make syntax is compatible between different versions of make; 2357however the special variables, variable modifiers and conditionals are not. 2358.Ss Older versions 2359An incomplete list of changes in older versions of 2360.Nm : 2361.Pp 2362The way that .for loop variables are substituted changed after 2363.Nx 5.0 2364so that they still appear to be variable expansions. 2365In particular this stops them being treated as syntax, and removes some 2366obscure problems using them in .if statements. 2367.Pp 2368The way that parallel makes are scheduled changed in 2369.Nx 4.0 2370so that .ORDER and .WAIT apply recursively to the dependent nodes. 2371The algorithms used may change again in the future. 2372.Ss Other make dialects 2373Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not 2374support most of the features of 2375.Nm 2376as described in this manual. 2377Most notably: 2378.Bl -bullet -offset indent 2379.It 2380The 2381.Ic .WAIT 2382and 2383.Ic .ORDER 2384declarations and most functionality pertaining to parallelization. 2385(GNU make supports parallelization but lacks these features needed to 2386control it effectively.) 2387.It 2388Directives, including for loops and conditionals and most of the 2389forms of include files. 2390(GNU make has its own incompatible and less powerful syntax for 2391conditionals.) 2392.It 2393All built-in variables that begin with a dot. 2394.It 2395Most of the special sources and targets that begin with a dot, 2396with the notable exception of 2397.Ic .PHONY , 2398.Ic .PRECIOUS , 2399and 2400.Ic .SUFFIXES . 2401.It 2402Variable modifiers, except for the 2403.Dl :old=new 2404string substitution, which does not portably support globbing with 2405.Ql % 2406and historically only works on declared suffixes. 2407.It 2408The 2409.Ic $> 2410variable even in its short form; most makes support this functionality 2411but its name varies. 2412.El 2413.Pp 2414Some features are somewhat more portable, such as assignment with 2415.Ic += , 2416.Ic ?= , 2417and 2418.Ic != . 2419The 2420.Ic .PATH 2421functionality is based on an older feature 2422.Ic VPATH 2423found in GNU make and many versions of SVR4 make; however, 2424historically its behavior is too ill-defined (and too buggy) to rely 2425upon. 2426.Pp 2427The 2428.Ic $@ 2429and 2430.Ic $< 2431variables are more or less universally portable, as is the 2432.Ic $(MAKE) 2433variable. 2434Basic use of suffix rules (for files only in the current directory, 2435not trying to chain transformations together, etc.) is also reasonably 2436portable. 2437.Sh SEE ALSO 2438.Xr mkdep 1 2439.Sh HISTORY 2440A 2441.Nm 2442command appeared in 2443.At v7 . 2444This 2445.Nm 2446implementation is based on Adam De Boor's pmake program which was written 2447for Sprite at Berkeley. 2448It was designed to be a parallel distributed make running jobs on different 2449machines using a daemon called 2450.Dq customs . 2451.Pp 2452Historically the target/dependency 2453.Dq FRC 2454has been used to FoRCe rebuilding (since the target/dependency 2455does not exist... unless someone creates an 2456.Dq FRC 2457file). 2458.Sh BUGS 2459The 2460.Nm 2461syntax is difficult to parse without actually acting on the data. 2462For instance, finding the end of a variable's use should involve scanning 2463each of the modifiers, using the correct terminator for each field. 2464In many places 2465.Nm 2466just counts {} and () in order to find the end of a variable expansion. 2467.Pp 2468There is no way of escaping a space character in a filename. 2469