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