aboutsummaryrefslogtreecommitdiffstats
path: root/make.1
blob: 91f366d3b3d2cb0eaed50d67260f3cbf018a54ca (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
.\"	$NetBSD: make.1,v 1.226 2013/11/07 18:50:46 dholland Exp $
.\"
.\" Copyright (c) 1990, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	from: @(#)make.1	8.4 (Berkeley) 3/19/94
.\"
.Dd October 25, 2013
.Dt MAKE 1
.Os
.Sh NAME
.Nm make
.Nd maintain program dependencies
.Sh SYNOPSIS
.Nm
.Op Fl BeikNnqrstWwX
.Op Fl C Ar directory
.Op Fl D Ar variable
.Op Fl d Ar flags
.Op Fl f Ar makefile
.Op Fl I Ar directory
.Op Fl J Ar private
.Op Fl j Ar max_jobs
.Op Fl m Ar directory
.Op Fl T Ar file
.Op Fl V Ar variable
.Op Ar variable=value
.Op Ar target ...
.Sh DESCRIPTION
.Nm
is a program designed to simplify the maintenance of other programs.
Its input is a list of specifications as to the files upon which programs
and other files depend.
If no
.Fl f Ar makefile
makefile option is given,
.Nm
will try to open
.Ql Pa makefile
then
.Ql Pa Makefile
in order to find the specifications.
If the file
.Ql Pa .depend
exists, it is read (see
.Xr mkdep 1 ) .
.Pp
This manual page is intended as a reference document only.
For a more thorough description of
.Nm
and makefiles, please refer to
.%T "PMake \- A Tutorial" .
.Pp
.Nm
will prepend the contents of the
.Va MAKEFLAGS
environment variable to the command line arguments before parsing them.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl B
Try to be backwards compatible by executing a single shell per command and
by executing the commands to make the sources of a dependency line in sequence.
.It Fl C Ar directory
Change to
.Ar directory
before reading the makefiles or doing anything else.
If multiple
.Fl C
options are specified, each is interpreted relative to the previous one:
.Fl C Pa / Fl C Pa etc
is equivalent to
.Fl C Pa /etc .
.It Fl D Ar variable
Define
.Ar variable
to be 1, in the global context.
.It Fl d Ar [-]flags
Turn on debugging, and specify which portions of
.Nm
are to print debugging information.
Unless the flags are preceded by
.Ql \-
they are added to the
.Va MAKEFLAGS
environment variable and will be processed by any child make processes.
By default, debugging information is printed to standard error,
but this can be changed using the
.Ar F
debugging flag.
The debugging output is always unbuffered; in addition, if debugging
is enabled but debugging output is not directed to standard output,
then the standard output is line buffered.
.Ar Flags
is one or more of the following:
.Bl -tag -width Ds
.It Ar A
Print all possible debugging information;
equivalent to specifying all of the debugging flags.
.It Ar a
Print debugging information about archive searching and caching.
.It Ar C
Print debugging information about current working directory.
.It Ar c
Print debugging information about conditional evaluation.
.It Ar d
Print debugging information about directory searching and caching.
.It Ar e
Print debugging information about failed commands and targets.
.It Ar F Ns Oo Sy \&+ Oc Ns Ar filename
Specify where debugging output is written.
This must be the last flag, because it consumes the remainder of
the argument.
If the character immediately after the
.Ql F
flag is
.Ql \&+ ,
then the file will be opened in append mode;
otherwise the file will be overwritten.
If the file name is
.Ql stdout
or
.Ql stderr
then debugging output will be written to the
standard output or standard error output file descriptors respectively
(and the
.Ql \&+
option has no effect).
Otherwise, the output will be written to the named file.
If the file name ends
.Ql .%d
then the
.Ql %d
is replaced by the pid.
.It Ar f
Print debugging information about loop evaluation.
.It Ar "g1"
Print the input graph before making anything.
.It Ar "g2"
Print the input graph after making everything, or before exiting
on error.
.It Ar "g3"
Print the input graph before exiting on error.
.It Ar j
Print debugging information about running multiple shells.
.It Ar l
Print commands in Makefiles regardless of whether or not they are prefixed by
.Ql @
or other "quiet" flags.
Also known as "loud" behavior.
.It Ar M
Print debugging information about "meta" mode decisions about targets.
.It Ar m
Print debugging information about making targets, including modification
dates.
.It Ar n
Don't delete the temporary command scripts created when running commands.
These temporary scripts are created in the directory
referred to by the
.Ev TMPDIR
environment variable, or in
.Pa /tmp
if
.Ev TMPDIR
is unset or set to the empty string.
The temporary scripts are created by
.Xr mkstemp 3 ,
and have names of the form
.Pa makeXXXXXX .
.Em NOTE :
This can create many files in
.Ev TMPDIR
or
.Pa /tmp ,
so use with care.
.It Ar p
Print debugging information about makefile parsing.
.It Ar s
Print debugging information about suffix-transformation rules.
.It Ar t
Print debugging information about target list maintenance.
.It Ar V
Force the
.Fl V
option to print raw values of variables.
.It Ar v
Print debugging information about variable assignment.
.It Ar w
Print entering and leaving directory messages, pre and post processing.
.It Ar x
Run shell commands with
.Fl x
so the actual commands are printed as they are executed.
.El
.It Fl e
Specify that environment variables override macro assignments within
makefiles.
.It Fl f Ar makefile
Specify a makefile to read instead of the default
.Ql Pa makefile .
If
.Ar makefile
is
.Ql Fl ,
standard input is read.
Multiple makefiles may be specified, and are read in the order specified.
.It Fl I Ar directory
Specify a directory in which to search for makefiles and included makefiles.
The system makefile directory (or directories, see the
.Fl m
option) is automatically included as part of this list.
.It Fl i
Ignore non-zero exit of shell commands in the makefile.
Equivalent to specifying
.Ql Fl
before each command line in the makefile.
.It Fl J Ar private
This option should
.Em not
be specified by the user.
.Pp
When the
.Ar j
option is in use in a recursive build, this option is passed by a make
to child makes to allow all the make processes in the build to
cooperate to avoid overloading the system.
.It Fl j Ar max_jobs
Specify the maximum number of jobs that
.Nm
may have running at any one time.
The value is saved in
.Va .MAKE.JOBS .
Turns compatibility mode off, unless the
.Ar B
flag is also specified.
When compatibility mode is off, all commands associated with a
target are executed in a single shell invocation as opposed to the
traditional one shell invocation per line.
This can break traditional scripts which change directories on each
command invocation and then expect to start with a fresh environment
on the next line.
It is more efficient to correct the scripts rather than turn backwards
compatibility on.
.It Fl k
Continue processing after errors are encountered, but only on those targets
that do not depend on the target whose creation caused the error.
.It Fl m Ar directory
Specify a directory in which to search for sys.mk and makefiles included
via the
.Ao Ar file Ac Ns -style
include statement.
The
.Fl m
option can be used multiple times to form a search path.
This path will override the default system include path: /usr/share/mk.
Furthermore the system include path will be appended to the search path used
for
.Qo Ar file Qc Ns -style
include statements (see the
.Fl I
option).
.Pp
If a file or directory name in the
.Fl m
argument (or the
.Ev MAKESYSPATH
environment variable) starts with the string
.Qq \&.../
then
.Nm
will search for the specified file or directory named in the remaining part
of the argument string.
The search starts with the current directory of
the Makefile and then works upward towards the root of the filesystem.
If the search is successful, then the resulting directory replaces the
.Qq \&.../
specification in the
.Fl m
argument.
If used, this feature allows
.Nm
to easily search in the current source tree for customized sys.mk files
(e.g., by using
.Qq \&.../mk/sys.mk
as an argument).
.It Fl n
Display the commands that would have been executed, but do not
actually execute them unless the target depends on the .MAKE special
source (see below).
.It Fl N
Display the commands which would have been executed, but do not
actually execute any of them; useful for debugging top-level makefiles
without descending into subdirectories.
.It Fl q
Do not execute any commands, but exit 0 if the specified targets are
up-to-date and 1, otherwise.
.It Fl r
Do not use the built-in rules specified in the system makefile.
.It Fl s
Do not echo any commands as they are executed.
Equivalent to specifying
.Ql Ic @
before each command line in the makefile.
.It Fl T Ar tracefile
When used with the
.Fl j
flag,
append a trace record to
.Ar tracefile
for each job started and completed.
.It Fl t
Rather than re-building a target as specified in the makefile, create it
or update its modification time to make it appear up-to-date.
.It Fl V Ar variable
Print
.Nm Ns 's
idea of the value of
.Ar variable ,
in the global context.
Do not build any targets.
Multiple instances of this option may be specified;
the variables will be printed one per line,
with a blank line for each null or undefined variable.
If
.Ar variable
contains a
.Ql \&$
then the value will be expanded before printing.
.It Fl W
Treat any warnings during makefile parsing as errors.
.It Fl X
Don't export variables passed on the command line to the environment
individually.
Variables passed on the command line are still exported
via the
.Va MAKEFLAGS
environment variable.
This option may be useful on systems which have a small limit on the
size of command arguments.
.It Ar variable=value
Set the value of the variable
.Ar variable
to
.Ar value .
Normally, all values passed on the command line are also exported to
sub-makes in the environment.
The
.Fl X
flag disables this behavior.
Variable assignments should follow options for POSIX compatibility
but no ordering is enforced.
.El
.Pp
There are seven different types of lines in a makefile: file dependency
specifications, shell commands, variable assignments, include statements,
conditional directives, for loops, and comments.
.Pp
In general, lines may be continued from one line to the next by ending
them with a backslash
.Pq Ql \e .
The trailing newline character and initial whitespace on the following
line are compressed into a single space.
.Sh FILE DEPENDENCY SPECIFICATIONS
Dependency lines consist of one or more targets, an operator, and zero
or more sources.
This creates a relationship where the targets
.Dq depend
on the sources
and are usually created from them.
The exact relationship between the target and the source is determined
by the operator that separates them.
The three operators are as follows:
.Bl -tag -width flag
.It Ic \&:
A target is considered out-of-date if its modification time is less than
those of any of its sources.
Sources for a target accumulate over dependency lines when this operator
is used.
The target is removed if
.Nm
is interrupted.
.It Ic \&!
Targets are always re-created, but not until all sources have been
examined and re-created as necessary.
Sources for a target accumulate over dependency lines when this operator
is used.
The target is removed if
.Nm
is interrupted.
.It Ic \&::
If no sources are specified, the target is always re-created.
Otherwise, a target is considered out-of-date if any of its sources has
been modified more recently than the target.
Sources for a target do not accumulate over dependency lines when this
operator is used.
The target will not be removed if
.Nm
is interrupted.
.El
.Pp
Targets and sources may contain the shell wildcard values
.Ql \&? ,
.Ql * ,
.Ql [] ,
and
.Ql {} .
The values
.Ql \&? ,
.Ql * ,
and
.Ql []
may only be used as part of the final
component of the target or source, and must be used to describe existing
files.
The value
.Ql {}
need not necessarily be used to describe existing files.
Expansion is in directory order, not alphabetically as done in the shell.
.Sh SHELL COMMANDS
Each target may have associated with it a series of shell commands, normally
used to create the target.
Each of the commands in this script
.Em must
be preceded by a tab.
While any target may appear on a dependency line, only one of these
dependencies may be followed by a creation script, unless the
.Ql Ic \&::
operator is used.
.Pp
If the first characters of the command line are any combination of
.Ql Ic @ ,
.Ql Ic + ,
or
.Ql Ic \- ,
the command is treated specially.
A
.Ql Ic @
causes the command not to be echoed before it is executed.
A
.Ql Ic +
causes the command to be executed even when
.Fl n
is given.
This is similar to the effect of the .MAKE special source,
except that the effect can be limited to a single line of a script.
A
.Ql Ic \-
causes any non-zero exit status of the command line to be ignored.
.Pp
When
.Nm
is run in jobs mode with
.Fl j Ar max_jobs ,
the entire script for the target is fed to a
single instance of the shell.
.Pp
In compatibility (non-jobs) mode, each command is run in a separate process.
If the command contains any shell meta characters
.Pq Ql #=|^(){};&<>*?[]:$`\e\en
it will be passed to the shell, otherwise
.Nm
will attempt direct execution.
.Pp
Since
.Nm
will
.Xr chdir 2
to
.Ql Va .OBJDIR
before executing any targets, each child process
starts with that as its current working directory.
.Pp
Makefiles should be written so that the mode of
.Nm
operation does not change their behavior.
For example, any command which needs to use
.Dq cd
or
.Dq chdir ,
without side-effect should be put in parenthesis:
.Bd -literal -offset indent

avoid-chdir-side-effects:
	@echo Building $@ in `pwd`
	@(cd ${.CURDIR} && ${.MAKE} $@)
	@echo Back in `pwd`

ensure-one-shell-regardless-of-mode:
	@echo Building $@ in `pwd`; \\
	(cd ${.CURDIR} && ${.MAKE} $@); \\
	echo Back in `pwd`
.Ed
.Sh VARIABLE ASSIGNMENTS
Variables in make are much like variables in the shell, and, by tradition,
consist of all upper-case letters.
.Ss Variable assignment modifiers
The five operators that can be used to assign values to variables are as
follows:
.Bl -tag -width Ds
.It Ic \&=
Assign the value to the variable.
Any previous value is overridden.
.It Ic \&+=
Append the value to the current value of the variable.
.It Ic \&?=
Assign the value to the variable if it is not already defined.
.It Ic \&:=
Assign with expansion, i.e. expand the value before assigning it
to the variable.
Normally, expansion is not done until the variable is referenced.
.Em NOTE :
References to undefined variables are
.Em not
expanded.
This can cause problems when variable modifiers are used.
.It Ic \&!=
Expand the value and pass it to the shell for execution and assign
the result to the variable.
Any newlines in the result are replaced with spaces.
.El
.Pp
Any white-space before the assigned
.Ar value
is removed; if the value is being appended, a single space is inserted
between the previous contents of the variable and the appended value.
.Pp
Variables are expanded by surrounding the variable name with either
curly braces
.Pq Ql {}
or parentheses
.Pq Ql ()
and preceding it with
a dollar sign
.Pq Ql \&$ .
If the variable name contains only a single letter, the surrounding
braces or parentheses are not required.
This shorter form is not recommended.
.Pp
If the variable name contains a dollar, then the name itself is expanded first.
This allows almost arbitrary variable names, however names containing dollar,
braces, parenthesis, or whitespace are really best avoided!
.Pp
If the result of expanding a variable contains a dollar sign
.Pq Ql \&$
the string is expanded again.
.Pp
Variable substitution occurs at three distinct times, depending on where
the variable is being used.
.Bl -enum
.It
Variables in dependency lines are expanded as the line is read.
.It
Variables in shell commands are expanded when the shell command is
executed.
.It
.Dq .for
loop index variables are expanded on each loop iteration.
Note that other variables are not expanded inside loops so
the following example code:
.Bd -literal -offset indent

.Dv .for i in 1 2 3
a+=     ${i}
j=      ${i}
b+=     ${j}
.Dv .endfor

all:
	@echo ${a}
	@echo ${b}

.Ed
will print:
.Bd -literal -offset indent
1 2 3
3 3 3

.Ed
Because while ${a} contains
.Dq 1 2 3
after the loop is executed, ${b}
contains
.Dq ${j} ${j} ${j}
which expands to
.Dq 3 3 3
since after the loop completes ${j} contains
.Dq 3 .
.El
.Ss Variable classes
The four different classes of variables (in order of increasing precedence)
are:
.Bl -tag -width Ds
.It Environment variables
Variables defined as part of
.Nm Ns 's
environment.
.It Global variables
Variables defined in the makefile or in included makefiles.
.It Command line variables
Variables defined as part of the command line.
.It Local variables
Variables that are defined specific to a certain target.
The seven local variables are as follows:
.Bl -tag -width ".ARCHIVE"
.It Va .ALLSRC
The list of all sources for this target; also known as
.Ql Va \&\*[Gt] .
.It Va .ARCHIVE
The name of the archive file.
.It Va .IMPSRC
In suffix-transformation rules, the name/path of the source from which the
target is to be transformed (the
.Dq implied
source); also known as
.Ql Va \&\*[Lt] .
It is not defined in explicit rules.
.It Va .MEMBER
The name of the archive member.
.It Va .OODATE
The list of sources for this target that were deemed out-of-date; also
known as
.Ql Va \&? .
.It Va .PREFIX
The file prefix of the target, containing only the file portion, no suffix
or preceding directory components; also known as
.Ql Va * .
.It Va .TARGET
The name of the target; also known as
.Ql Va @ .
.El
.Pp
The shorter forms
.Ql Va @ ,
.Ql Va \&? ,
.Ql Va \&\*[Lt] ,
.Ql Va \&\*[Gt] ,
and
.Ql Va *
are permitted for backward
compatibility with historical makefiles and are not recommended.
The six variables
.Ql Va "@F" ,
.Ql Va "@D" ,
.Ql Va "\*[Lt]F" ,
.Ql Va "\*[Lt]D" ,
.Ql Va "*F" ,
and
.Ql Va "*D"
are permitted for compatibility with
.At V
makefiles and are not recommended.
.Pp
Four of the local variables may be used in sources on dependency lines
because they expand to the proper value for each target on the line.
These variables are
.Ql Va .TARGET ,
.Ql Va .PREFIX ,
.Ql Va .ARCHIVE ,
and
.Ql Va .MEMBER .
.El
.Ss Additional built-in variables
In addition,
.Nm
sets or knows about the following variables:
.Bl -tag -width .MAKEOVERRIDES
.It Va \&$
A single dollar sign
.Ql \&$ ,
i.e.
.Ql \&$$
expands to a single dollar
sign.
.It Va .ALLTARGETS
The list of all targets encountered in the Makefile.
If evaluated during
Makefile parsing, lists only those targets encountered thus far.
.It Va .CURDIR
A path to the directory where
.Nm
was executed.
Refer to the description of
.Ql Ev PWD
for more details.
.It Ev MAKE
The name that
.Nm
was executed with
.Pq Va argv[0] .
For compatibility
.Nm
also sets
.Va .MAKE
with the same value.
The preferred variable to use is the environment variable
.Ev MAKE
because it is more compatible with other versions of
.Nm
and cannot be confused with the special target with the same name.
.It Va .MAKE.DEPENDFILE
Names the makefile (default
.Ql Pa .depend )
from which generated dependencies are read.
.It Va .MAKE.EXPAND_VARIABLES
A boolean that controls the default behavior of the
.Fl V
option.
.It Va .MAKE.EXPORTED
The list of variables exported by
.Nm .
.It Va .MAKE.JOBS
The argument to the
.Fl j
option.
.It Va .MAKE.JOB.PREFIX
If
.Nm
is run with
.Ar j
then output for each target is prefixed with a token
.Ql --- target ---
the first part of which can be controlled via
.Va .MAKE.JOB.PREFIX .
If
.Va .MAKE.JOB.PREFIX
is empty, no token is printed.
.br
For example:
.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
would produce tokens like
.Ql ---make[1234] target ---
making it easier to track the degree of parallelism being achieved.
.It Ev MAKEFLAGS
The environment variable
.Ql Ev MAKEFLAGS
may contain anything that
may be specified on
.Nm Ns 's
command line.
Anything specified on
.Nm Ns 's
command line is appended to the
.Ql Ev MAKEFLAGS
variable which is then
entered into the environment for all programs which
.Nm
executes.
.It Va .MAKE.LEVEL
The recursion depth of
.Nm .
The initial instance of
.Nm
will be 0, and an incremented value is put into the environment
to be seen by the next generation.
This allows tests like:
.Li .if ${.MAKE.LEVEL} == 0
to protect things which should only be evaluated in the initial instance of
.Nm .
.It Va .MAKE.MAKEFILE_PREFERENCE
The ordered list of makefile names
(default
.Ql Pa makefile ,
.Ql Pa Makefile )
that
.Nm
will look for.
.It Va .MAKE.MAKEFILES
The list of makefiles read by
.Nm ,
which is useful for tracking dependencies.
Each makefile is recorded only once, regardless of the number of times read.
.It Va .MAKE.MODE
Processed after reading all makefiles.
Can affect the mode that
.Nm
runs in.
It can contain a number of keywords:
.Bl -hang -width ignore-cmd
.It Pa compat
Like
.Fl B ,
puts
.Nm
into "compat" mode.
.It Pa meta
Puts
.Nm
into "meta" mode, where meta files are created for each target
to capture the command run, the output generated and if
.Xr filemon 4
is available, the system calls which are of interest to
.Nm .
The captured output can be very useful when diagnosing errors.
.It Pa curdirOk= Ar bf
Normally
.Nm
will not create .meta files in
.Ql Va .CURDIR .
This can be overridden by setting
.Va bf
to a value which represents True.
.It Pa env
For debugging, it can be useful to inlcude the environment
in the .meta file.
.It Pa verbose
If in "meta" mode, print a clue about the target being built.
This is useful if the build is otherwise running silently.
The message printed the value of:
.Va .MAKE.META.PREFIX .
.It Pa ignore-cmd
Some makefiles have commands which are simply not stable.
This keyword causes them to be ignored for
determining whether a target is out of date in "meta" mode.
See also
.Ic .NOMETA_CMP .
.It Pa silent= Ar bf
If
.Va bf
is True, when a .meta file is created, mark the target
.Ic .SILENT .
.El
.It Va .MAKE.META.BAILIWICK
In "meta" mode, provides a list of prefixes which
match the directories controlled by
.Nm .
If a file that was generated outside of
.Va .OBJDIR
but within said bailiwick is missing,
the current target is considered out-of-date.
.It Va .MAKE.META.CREATED
In "meta" mode, this variable contains a list of all the meta files
updated.
If not empty, it can be used to trigger processing of
.Va .MAKE.META.FILES .
.It Va .MAKE.META.FILES
In "meta" mode, this variable contains a list of all the meta files
used (updated or not).
This list can be used to process the meta files to extract dependency
information.
.It Va .MAKE.META.IGNORE_PATHS
Provides a list of path prefixes that should be ignored;
because the contents are expected to change over time.
The default list includes:
.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
.It Va .MAKE.META.PREFIX
Defines the message printed for each meta file updated in "meta verbose" mode.
The default value is:
.Dl Building ${.TARGET:H:tA}/${.TARGET:T}
.It Va .MAKEOVERRIDES
This variable is used to record the names of variables assigned to
on the command line, so that they may be exported as part of
.Ql Ev MAKEFLAGS .
This behaviour can be disabled by assigning an empty value to
.Ql Va .MAKEOVERRIDES
within a makefile.
Extra variables can be exported from a makefile
by appending their names to
.Ql Va .MAKEOVERRIDES .
.Ql Ev MAKEFLAGS
is re-exported whenever
.Ql Va .MAKEOVERRIDES
is modified.
.It Va .MAKE.PATH_FILEMON
If
.Nm
was built with
.Xr filemon 4
support, this is set to the path of the device node.
This allows makefiles to test for this support.
.It Va .MAKE.PID
The process-id of
.Nm .
.It Va .MAKE.PPID
The parent process-id of
.Nm .
.It Va MAKE_PRINT_VAR_ON_ERROR
When
.Nm
stops due to an error, it prints its name and the value of
.Ql Va .CURDIR
as well as the value of any variables named in
.Ql Va MAKE_PRINT_VAR_ON_ERROR .
.It Va .newline
This variable is simply assigned a newline character as its value.
This allows expansions using the
.Cm \&:@
modifier to put a newline between
iterations of the loop rather than a space.
For example, the printing of
.Ql Va MAKE_PRINT_VAR_ON_ERROR
could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
.It Va .OBJDIR
A path to the directory where the targets are built.
Its value is determined by trying to
.Xr chdir 2
to the following directories in order and using the first match:
.Bl -enum
.It
.Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
.Pp
(Only if
.Ql Ev MAKEOBJDIRPREFIX
is set in the environment or on the command line.)
.It
.Ev ${MAKEOBJDIR}
.Pp
(Only if
.Ql Ev MAKEOBJDIR
is set in the environment or on the command line.)
.It
.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
.It
.Ev ${.CURDIR} Ns Pa /obj
.It
.Pa /usr/obj/ Ns Ev ${.CURDIR}
.It
.Ev ${.CURDIR}
.El
.Pp
Variable expansion is performed on the value before it's used,
so expressions such as
.Dl ${.CURDIR:S,^/usr/src,/var/obj,}
may be used.
This is especially useful with
.Ql Ev MAKEOBJDIR .
.Pp
.Ql Va .OBJDIR
may be modified in the makefile as a global variable.
In all cases,
.Nm
will
.Xr chdir 2
to
.Ql Va .OBJDIR
and set
.Ql Ev PWD
to that directory before executing any targets.
.
.It Va .PARSEDIR
A path to the directory of the current
.Ql Pa Makefile
being parsed.
.It Va .PARSEFILE
The basename of the current
.Ql Pa Makefile
being parsed.
This variable and
.Ql Va .PARSEDIR
are both set only while the
.Ql Pa Makefiles
are being parsed.
If you want to retain their current values, assign them to a variable
using assignment with expansion:
.Pq Ql Cm \&:= .
.It Va .PATH
A variable that represents the list of directories that
.Nm
will search for files.
The search list should be updated using the target
.Ql Va .PATH
rather than the variable.
.It Ev PWD
Alternate path to the current directory.
.Nm
normally sets
.Ql Va .CURDIR
to the canonical path given by
.Xr getcwd 3 .
However, if the environment variable
.Ql Ev PWD
is set and gives a path to the current directory, then
.Nm
sets
.Ql Va .CURDIR
to the value of
.Ql Ev PWD
instead.
This behaviour is disabled if
.Ql Ev MAKEOBJDIRPREFIX
is set or
.Ql Ev MAKEOBJDIR
contains a variable transform.
.Ql Ev PWD
is set to the value of
.Ql Va .OBJDIR
for all programs which
.Nm
executes.
.It Ev .TARGETS
The list of targets explicitly specified on the command line, if any.
.It Ev VPATH
Colon-separated
.Pq Dq \&:
lists of directories that
.Nm
will search for files.
The variable is supported for compatibility with old make programs only,
use
.Ql Va .PATH
instead.
.El
.Ss Variable modifiers
Variable expansion may be modified to select or modify each word of the
variable (where a
.Dq word
is white-space delimited sequence of characters).
The general format of a variable expansion is as follows:
.Pp
.Dl ${variable[:modifier[:...]]}
.Pp
Each modifier begins with a colon,
which may be escaped with a backslash
.Pq Ql \e .
.Pp
A set of modifiers can be specified via a variable, as follows:
.Pp
.Dl modifier_variable=modifier[:...]
.Dl ${variable:${modifier_variable}[:...]}
.Pp
In this case the first modifier in the modifier_variable does not
start with a colon, since that must appear in the referencing
variable.
If any of the modifiers in the modifier_variable contain a dollar sign
.Pq Ql $ ,
these must be doubled to avoid early expansion.
.Pp
The supported modifiers are:
.Bl -tag -width EEE
.It Cm \&:E
Replaces each word in the variable with its suffix.
.It Cm \&:H
Replaces each word in the variable with everything but the last component.
.It Cm \&:M Ns Ar pattern
Select only those words that match
.Ar pattern .
The standard shell wildcard characters
.Pf ( Ql * ,
.Ql \&? ,
and
.Ql Oo Oc )
may
be used.
The wildcard characters may be escaped with a backslash
.Pq Ql \e .
As a consequence of the way values are split into words, matched,
and then joined, a construct like
.Dl ${VAR:M*}
will normalise the inter-word spacing, removing all leading and
trailing space, and converting multiple consecutive spaces
to single spaces.
.
.It Cm \&:N Ns Ar pattern
This is identical to
.Ql Cm \&:M ,
but selects all words which do not match
.Ar pattern .
.It Cm \&:O
Order every word in variable alphabetically.
To sort words in
reverse order use the
.Ql Cm \&:O:[-1..1]
combination of modifiers.
.It Cm \&:Ox
Randomize words in variable.
The results will be different each time you are referring to the
modified variable; use the assignment with expansion
.Pq Ql Cm \&:=
to prevent such behaviour.
For example,
.Bd -literal -offset indent
LIST=			uno due tre quattro
RANDOM_LIST=		${LIST:Ox}
STATIC_RANDOM_LIST:=	${LIST:Ox}

all:
	@echo "${RANDOM_LIST}"
	@echo "${RANDOM_LIST}"
	@echo "${STATIC_RANDOM_LIST}"
	@echo "${STATIC_RANDOM_LIST}"
.Ed
may produce output similar to:
.Bd -literal -offset indent
quattro due tre uno
tre due quattro uno
due uno quattro tre
due uno quattro tre
.Ed
.It Cm \&:Q
Quotes every shell meta-character in the variable, so that it can be passed
safely through recursive invocations of
.Nm .
.It Cm \&:R
Replaces each word in the variable with everything but its suffix.
.It Cm \&:gmtime
The value is a format string for
.Xr strftime 3 ,
using the current
.Xr gmtime 3 .
.It Cm \&:hash
Compute a 32bit hash of the value and encode it as hex digits.
.It Cm \&:localtime
The value is a format string for
.Xr strftime 3 ,
using the current
.Xr localtime 3 .
.It Cm \&:tA
Attempt to convert variable to an absolute path using
.Xr realpath 3 ,
if that fails, the value is unchanged.
.It Cm \&:tl
Converts variable to lower-case letters.
.It Cm \&:ts Ns Ar c
Words in the variable are normally separated by a space on expansion.
This modifier sets the separator to the character
.Ar c .
If
.Ar c
is omitted, then no separator is used.
The common escapes (including octal numeric codes), work as expected.
.It Cm \&:tu
Converts variable to upper-case letters.
.It Cm \&:tW
Causes the value to be treated as a single word
(possibly containing embedded white space).
See also
.Ql Cm \&:[*] .
.It Cm \&:tw
Causes the value to be treated as a sequence of
words delimited by white space.
See also
.Ql Cm \&:[@] .
.Sm off
.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
.Sm on
Modify the first occurrence of
.Ar old_string
in the variable's value, replacing it with
.Ar new_string .
If a
.Ql g
is appended to the last slash of the pattern, all occurrences
in each word are replaced.
If a
.Ql 1
is appended to the last slash of the pattern, only the first word
is affected.
If a
.Ql W
is appended to the last slash of the pattern,
then the value is treated as a single word
(possibly containing embedded white space).
If
.Ar old_string
begins with a caret
.Pq Ql ^ ,
.Ar old_string
is anchored at the beginning of each word.
If
.Ar old_string
ends with a dollar sign
.Pq Ql \&$ ,
it is anchored at the end of each word.
Inside
.Ar new_string ,
an ampersand
.Pq Ql \*[Am]
is replaced by
.Ar old_string
(without any
.Ql ^
or
.Ql \&$ ) .
Any character may be used as a delimiter for the parts of the modifier
string.
The anchoring, ampersand and delimiter characters may be escaped with a
backslash
.Pq Ql \e .
.Pp
Variable expansion occurs in the normal fashion inside both
.Ar old_string
and
.Ar new_string
with the single exception that a backslash is used to prevent the expansion
of a dollar sign
.Pq Ql \&$ ,
not a preceding dollar sign as is usual.
.Sm off
.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
.Sm on
The
.Cm \&:C
modifier is just like the
.Cm \&:S
modifier except that the old and new strings, instead of being
simple strings, are an extended regular expression (see
.Xr regex 3 )
string
.Ar pattern
and an
.Xr ed 1 Ns \-style
string
.Ar replacement .
Normally, the first occurrence of the pattern
.Ar pattern
in each word of the value is substituted with
.Ar replacement .
The
.Ql 1
modifier causes the substitution to apply to at most one word; the
.Ql g
modifier causes the substitution to apply to as many instances of the
search pattern
.Ar pattern
as occur in the word or words it is found in; the
.Ql W
modifier causes the value to be treated as a single word
(possibly containing embedded white space).
Note that
.Ql 1
and
.Ql g
are orthogonal; the former specifies whether multiple words are
potentially affected, the latter whether multiple substitutions can
potentially occur within each affected word.
.It Cm \&:T
Replaces each word in the variable with its last component.
.It Cm \&:u
Remove adjacent duplicate words (like
.Xr uniq 1 ) .
.Sm off
.It Cm \&:\&? Ar true_string Cm \&: Ar false_string
.Sm on
If the variable name (not its value), when parsed as a .if conditional
expression, evaluates to true, return as its value the
.Ar true_string ,
otherwise return the
.Ar false_string .
Since the variable name is used as the expression, \&:\&? must be the
first modifier after the variable name itself - which will, of course,
usually contain variable expansions.
A common error is trying to use expressions like
.Dl ${NUMBERS:M42:?match:no}
which actually tests defined(NUMBERS),
to determine is any words match "42" you need to use something like:
.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
.It Ar :old_string=new_string
This is the
.At V
style variable substitution.
It must be the last modifier specified.
If
.Ar old_string
or
.Ar new_string
do not contain the pattern matching character
.Ar %
then it is assumed that they are
anchored at the end of each word, so only suffixes or entire
words may be replaced.
Otherwise
.Ar %
is the substring of
.Ar old_string
to be replaced in
.Ar new_string .
.Pp
Variable expansion occurs in the normal fashion inside both
.Ar old_string
and
.Ar new_string
with the single exception that a backslash is used to prevent the
expansion of a dollar sign
.Pq Ql \&$ ,
not a preceding dollar sign as is usual.
.Sm off
.It Cm \&:@ Ar temp Cm @ Ar string Cm @
.Sm on
This is the loop expansion mechanism from the OSF Development
Environment (ODE) make.
Unlike
.Cm \&.for
loops expansion occurs at the time of
reference.
Assign
.Ar temp
to each word in the variable and evaluate
.Ar string .
The ODE convention is that
.Ar temp
should start and end with a period.
For example.
.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
.Pp
However a single character variable is often more readable:
.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
.It Cm \&:U Ns Ar newval
If the variable is undefined
.Ar newval
is the value.
If the variable is defined, the existing value is returned.
This is another ODE make feature.
It is handy for setting per-target CFLAGS for instance:
.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
If a value is only required if the variable is undefined, use:
.Dl ${VAR:D:Unewval}
.It Cm \&:D Ns Ar newval
If the variable is defined
.Ar newval
is the value.
.It Cm \&:L
The name of the variable is the value.
.It Cm \&:P
The path of the node which has the same name as the variable
is the value.
If no such node exists or its path is null, then the
name of the variable is used.
In order for this modifier to work, the name (node) must at least have
appeared on the rhs of a dependency.
.Sm off
.It Cm \&:\&! Ar cmd Cm \&!
.Sm on
The output of running
.Ar cmd
is the value.
.It Cm \&:sh
If the variable is non-empty it is run as a command and the output
becomes the new value.
.It Cm \&::= Ns Ar str
The variable is assigned the value
.Ar str
after substitution.
This modifier and its variations are useful in
obscure situations such as wanting to set a variable when shell commands
are being parsed.
These assignment modifiers always expand to
nothing, so if appearing in a rule line by themselves should be
preceded with something to keep
.Nm
happy.
.Pp
The
.Ql Cm \&::
helps avoid false matches with the
.At V
style
.Cm \&:=
modifier and since substitution always occurs the
.Cm \&::=
form is vaguely appropriate.
.It Cm \&::?= Ns Ar str
As for
.Cm \&::=
but only if the variable does not already have a value.
.It Cm \&::+= Ns Ar str
Append
.Ar str
to the variable.
.It Cm \&::!= Ns Ar cmd
Assign the output of
.Ar cmd
to the variable.
.It Cm \&:\&[ Ns Ar range Ns Cm \&]
Selects one or more words from the value,
or performs other operations related to the way in which the
value is divided into words.
.Pp
Ordinarily, a value is treated as a sequence of words
delimited by white space.
Some modifiers suppress this behaviour,
causing a value to be treated as a single word
(possibly containing embedded white space).
An empty value, or a value that consists entirely of white-space,
is treated as a single word.
For the purposes of the
.Ql Cm \&:[]
modifier, the words are indexed both forwards using positive integers
(where index 1 represents the first word),
and backwards using negative integers
(where index \-1 represents the last word).
.Pp
The
.Ar range
is subjected to variable expansion, and the expanded result is
then interpreted as follows:
.Bl -tag -width index
.\" :[n]
.It Ar index
Selects a single word from the value.
.\" :[start..end]
.It Ar start Ns Cm \&.. Ns Ar end
Selects all words from
.Ar start
to
.Ar end ,
inclusive.
For example,
.Ql Cm \&:[2..-1]
selects all words from the second word to the last word.
If
.Ar start
is greater than
.Ar end ,
then the words are output in reverse order.
For example,
.Ql Cm \&:[-1..1]
selects all the words from last to first.
.\" :[*]
.It Cm \&*
Causes subsequent modifiers to treat the value as a single word
(possibly containing embedded white space).
Analogous to the effect of
\&"$*\&"
in Bourne shell.
.\" :[0]
.It 0
Means the same as
.Ql Cm \&:[*] .
.\" :[*]
.It Cm \&@
Causes subsequent modifiers to treat the value as a sequence of words
delimited by white space.
Analogous to the effect of
\&"$@\&"
in Bourne shell.
.\" :[#]
.It Cm \&#
Returns the number of words in the value.
.El \" :[range]
.El
.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
Makefile inclusion, conditional structures and for loops  reminiscent
of the C programming language are provided in
.Nm .
All such structures are identified by a line beginning with a single
dot
.Pq Ql \&.
character.
Files are included with either
.Cm \&.include Aq Ar file
or
.Cm \&.include Pf \*q Ar file Ns \*q .
Variables between the angle brackets or double quotes are expanded
to form the file name.
If angle brackets are used, the included makefile is expected to be in
the system makefile directory.
If double quotes are used, the including makefile's directory and any
directories specified using the
.Fl I
option are searched before the system
makefile directory.
For compatibility with other versions of
.Nm
.Ql include file ...
is also accepted.
If the include statement is written as
.Cm .-include
or as
.Cm .sinclude
then errors locating and/or opening include files are ignored.
.Pp
Conditional expressions are also preceded by a single dot as the first
character of a line.
The possible conditionals are as follows:
.Bl -tag -width Ds
.It Ic .error Ar message
The message is printed along with the name of the makefile and line number,
then
.Nm
will exit.
.It Ic .export Ar variable ...
Export the specified global variable.
If no variable list is provided, all globals are exported
except for internal variables (those that start with
.Ql \&. ) .
This is not affected by the
.Fl X
flag, so should be used with caution.
For compatibility with other
.Nm
programs
.Ql export variable=value
is also accepted.
.Pp
Appending a variable name to
.Va .MAKE.EXPORTED
is equivalent to exporting a variable.
.It Ic .export-env Ar variable ...
The same as
.Ql .export ,
except that the variable is not appended to
.Va .MAKE.EXPORTED .
This allows exporting a value to the environment which is different from that
used by
.Nm
internally.
.It Ic .info Ar message
The message is printed along with the name of the makefile and line number.
.It Ic .undef Ar variable
Un-define the specified global variable.
Only global variables may be un-defined.
.It Ic .unexport Ar variable ...
The opposite of
.Ql .export .
The specified global
.Va variable
will be removed from
.Va .MAKE.EXPORTED .
If no variable list is provided, all globals are unexported,
and
.Va .MAKE.EXPORTED
deleted.
.It Ic .unexport-env
Unexport all globals previously exported and
clear the environment inherited from the parent.
This operation will cause a memory leak of the original environment,
so should be used sparingly.
Testing for
.Va .MAKE.LEVEL
being 0, would make sense.
Also note that any variables which originated in the parent environment
should be explicitly preserved if desired.
For example:
.Bd -literal -offset indent
.Li .if ${.MAKE.LEVEL} == 0
PATH := ${PATH}
.Li .unexport-env
.Li .export PATH
.Li .endif
.Pp
.Ed
Would result in an environment containing only
.Ql Ev PATH ,
which is the minimal useful environment.
Actually
.Ql Ev .MAKE.LEVEL
will also be pushed into the new environment.
.It Ic .warning Ar message
The message prefixed by
.Ql Pa warning:
is printed along with the name of the makefile and line number.
.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
Test the value of an expression.
.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
Test the value of a variable.
.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
Test the value of a variable.
.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
Test the target being built.
.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
Test the target being built.
.It Ic .else
Reverse the sense of the last conditional.
.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
A combination of
.Ql Ic .else
followed by
.Ql Ic .if .
.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
A combination of
.Ql Ic .else
followed by
.Ql Ic .ifdef .
.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
A combination of
.Ql Ic .else
followed by
.Ql Ic .ifndef .
.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
A combination of
.Ql Ic .else
followed by
.Ql Ic .ifmake .
.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
A combination of
.Ql Ic .else
followed by
.Ql Ic .ifnmake .
.It Ic .endif
End the body of the conditional.
.El
.Pp
The
.Ar operator
may be any one of the following:
.Bl -tag -width "Cm XX"
.It Cm \&|\&|
Logical OR.
.It Cm \&\*[Am]\*[Am]
Logical
.Tn AND ;
of higher precedence than
.Dq \&|\&| .
.El
.Pp
As in C,
.Nm
will only evaluate a conditional as far as is necessary to determine
its value.
Parentheses may be used to change the order of evaluation.
The boolean operator
.Ql Ic \&!
may be used to logically negate an entire
conditional.
It is of higher precedence than
.Ql Ic \&\*[Am]\*[Am] .
.Pp
The value of
.Ar expression
may be any of the following:
.Bl -tag -width defined
.It Ic defined
Takes a variable name as an argument and evaluates to true if the variable
has been defined.
.It Ic make
Takes a target name as an argument and evaluates to true if the target
was specified as part of
.Nm Ns 's
command line or was declared the default target (either implicitly or
explicitly, see
.Va .MAIN )
before the line containing the conditional.
.It Ic empty
Takes a variable, with possible modifiers, and evaluates to true if
the expansion of the variable would result in an empty string.
.It Ic exists
Takes a file name as an argument and evaluates to true if the file exists.
The file is searched for on the system search path (see
.Va .PATH ) .
.It Ic target
Takes a target name as an argument and evaluates to true if the target
has been defined.
.It Ic commands
Takes a target name as an argument and evaluates to true if the target
has been defined and has commands associated with it.
.El
.Pp
.Ar Expression
may also be an arithmetic or string comparison.
Variable expansion is
performed on both sides of the comparison, after which the integral
values are compared.
A value is interpreted as hexadecimal if it is
preceded by 0x, otherwise it is decimal; octal numbers are not supported.
The standard C relational operators are all supported.
If after
variable expansion, either the left or right hand side of a
.Ql Ic ==
or
.Ql Ic "!="
operator is not an integral value, then
string comparison is performed between the expanded
variables.
If no relational operator is given, it is assumed that the expanded
variable is being compared against 0 or an empty string in the case
of a string comparison.
.Pp
When
.Nm
is evaluating one of these conditional expressions, and it encounters
a (white-space separated) word it doesn't recognize, either the
.Dq make
or
.Dq defined
expression is applied to it, depending on the form of the conditional.
If the form is
.Ql Ic .ifdef ,
.Ql Ic .ifndef ,
or
.Ql Ic .if
the
.Dq defined
expression is applied.
Similarly, if the form is
.Ql Ic .ifmake
or
.Ql Ic .ifnmake , the
.Dq make
expression is applied.
.Pp
If the conditional evaluates to true the parsing of the makefile continues
as before.
If it evaluates to false, the following lines are skipped.
In both cases this continues until a
.Ql Ic .else
or
.Ql Ic .endif
is found.
.Pp
For loops are typically used to apply a set of rules to a list of files.
The syntax of a for loop is:
.Pp
.Bl -tag -compact -width Ds
.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
.It Aq make-rules
.It Ic \&.endfor
.El
.Pp
After the for
.Ic expression
is evaluated, it is split into words.
On each iteration of the loop, one word is taken and assigned to each
.Ic variable ,
in order, and these
.Ic variables
are substituted into the
.Ic make-rules
inside the body of the for loop.
The number of words must come out even; that is, if there are three
iteration variables, the number of words provided must be a multiple
of three.
.Sh COMMENTS
Comments begin with a hash
.Pq Ql \&#
character, anywhere but in a shell
command line, and continue to the end of an unescaped new line.
.Sh SPECIAL SOURCES (ATTRIBUTES)
.Bl -tag -width .IGNOREx
.It Ic .EXEC
Target is never out of date, but always execute commands anyway.
.It Ic .IGNORE
Ignore any errors from the commands associated with this target, exactly
as if they all were preceded by a dash
.Pq Ql \- .
.\" .It Ic .INVISIBLE
.\" XXX
.\" .It Ic .JOIN
.\" XXX
.It Ic .MADE
Mark all sources of this target as being up-to-date.
.It Ic .MAKE
Execute the commands associated with this target even if the
.Fl n
or
.Fl t
options were specified.
Normally used to mark recursive
.Nm Ns s .
.It Ic .META
Create a meta file for the target, even if it is flagged as
.Ic .PHONY ,
.Ic .MAKE ,
or
.Ic .SPECIAL .
Usage in conjunction with
.Ic .MAKE
is the most likely case.
In "meta" mode, the target is out-of-date if the meta file is missing.
.It Ic .NOMETA
Do not create a meta file for the target.
Meta files are also not created for
.Ic .PHONY ,
.Ic .MAKE ,
or
.Ic .SPECIAL
targets.
.It Ic .NOMETA_CMP
Ignore differences in commands when deciding if target is out of date.
This is useful if the command contains a value which always changes.
If the number of commands change, though, the target will still be out of date.
The same effect applies to any command line that uses the variable
.Va .OODATE ,
which can be used for that purpose even when not otherwise needed or desired:
.Bd -literal -offset indent

skip-compare-for-some:
	@echo this will be compared
	@echo this will not ${.OODATE:M.NOMETA_CMP}
	@echo this will also be compared

.Ed
The
.Cm \&:M
pattern suppresses any expansion of the unwanted variable.
.It Ic .NOPATH
Do not search for the target in the directories specified by
.Ic .PATH .
.It Ic .NOTMAIN
Normally
.Nm
selects the first target it encounters as the default target to be built
if no target was specified.
This source prevents this target from being selected.
.It Ic .OPTIONAL
If a target is marked with this attribute and
.Nm
can't figure out how to create it, it will ignore this fact and assume
the file isn't needed or already exists.
.It Ic .PHONY
The target does not
correspond to an actual file; it is always considered to be out of date,
and will not be created with the
.Fl t
option.
Suffix-transformation rules are not applied to
.Ic .PHONY
targets.
.It Ic .PRECIOUS
When
.Nm
is interrupted, it normally removes any partially made targets.
This source prevents the target from being removed.
.It Ic .RECURSIVE
Synonym for
.Ic .MAKE .
.It Ic .SILENT
Do not echo any of the commands associated with this target, exactly
as if they all were preceded by an at sign
.Pq Ql @ .
.It Ic .USE
Turn the target into
.Nm Ns 's
version of a macro.
When the target is used as a source for another target, the other target
acquires the commands, sources, and attributes (except for
.Ic .USE )
of the
source.
If the target already has commands, the
.Ic .USE
target's commands are appended
to them.
.It Ic .USEBEFORE
Exactly like
.Ic .USE ,
but prepend the
.Ic .USEBEFORE
target commands to the target.
.It Ic .WAIT
If
.Ic .WAIT
appears in a dependency line, the sources that precede it are
made before the sources that succeed it in the line.
Since the dependents of files are not made until the file itself
could be made, this also stops the dependents being built unless they
are needed for another branch of the dependency tree.
So given:
.Bd -literal
x: a .WAIT b
	echo x
a:
	echo a
b: b1
	echo b
b1:
	echo b1

.Ed
the output is always
.Ql a ,
.Ql b1 ,
.Ql b ,
.Ql x .
.br
The ordering imposed by
.Ic .WAIT
is only relevant for parallel makes.
.El
.Sh SPECIAL TARGETS
Special targets may not be included with other targets, i.e. they must be
the only target specified.
.Bl -tag -width .BEGINx
.It Ic .BEGIN
Any command lines attached to this target are executed before anything
else is done.
.It Ic .DEFAULT
This is sort of a
.Ic .USE
rule for any target (that was used only as a
source) that
.Nm
can't figure out any other way to create.
Only the shell script is used.
The
.Ic .IMPSRC
variable of a target that inherits
.Ic .DEFAULT Ns 's
commands is set
to the target's own name.
.It Ic .END
Any command lines attached to this target are executed after everything
else is done.
.It Ic .ERROR
Any command lines attached to this target are executed when another target fails.
The
.Ic .ERROR_TARGET
variable is set to the target that failed.
See also
.Ic MAKE_PRINT_VAR_ON_ERROR .
.It Ic .IGNORE
Mark each of the sources with the
.Ic .IGNORE
attribute.
If no sources are specified, this is the equivalent of specifying the
.Fl i
option.
.It Ic .INTERRUPT
If
.Nm
is interrupted, the commands for this target will be executed.
.It Ic .MAIN
If no target is specified when
.Nm
is invoked, this target will be built.
.It Ic .MAKEFLAGS
This target provides a way to specify flags for
.Nm
when the makefile is used.
The flags are as if typed to the shell, though the
.Fl f
option will have
no effect.
.\" XXX: NOT YET!!!!
.\" .It Ic .NOTPARALLEL
.\" The named targets are executed in non parallel mode.
.\" If no targets are
.\" specified, then all targets are executed in non parallel mode.
.It Ic .NOPATH
Apply the
.Ic .NOPATH
attribute to any specified sources.
.It Ic .NOTPARALLEL
Disable parallel mode.
.It Ic .NO_PARALLEL
Synonym for
.Ic .NOTPARALLEL ,
for compatibility with other pmake variants.
.It Ic .ORDER
The named targets are made in sequence.
This ordering does not add targets to the list of targets to be made.
Since the dependents of a target do not get built until the target itself
could be built, unless
.Ql a
is built by another part of the dependency graph,
the following is a dependency loop:
.Bd -literal
\&.ORDER: b a
b: a
.Ed
.Pp
The ordering imposed by
.Ic .ORDER
is only relevant for parallel makes.
.\" XXX: NOT YET!!!!
.\" .It Ic .PARALLEL
.\" The named targets are executed in parallel mode.
.\" If no targets are
.\" specified, then all targets are executed in parallel mode.
.It Ic .PATH
The sources are directories which are to be searched for files not
found in the current directory.
If no sources are specified, any previously specified directories are
deleted.
If the source is the special
.Ic .DOTLAST
target, then the current working
directory is searched last.
.It Ic .PATH. Ns Va suffix
Like
.Ic .PATH
but applies only to files with a particular suffix.
The suffix must have been previously declared with
.Ic .SUFFIXES .
.It Ic .PHONY
Apply the
.Ic .PHONY
attribute to any specified sources.
.It Ic .PRECIOUS
Apply the
.Ic .PRECIOUS
attribute to any specified sources.
If no sources are specified, the
.Ic .PRECIOUS
attribute is applied to every
target in the file.
.It Ic .SHELL
Sets the shell that
.Nm
will use to execute commands.
The sources are a set of
.Ar field=value
pairs.
.Bl -tag -width hasErrCtls
.It Ar name
This is the minimal specification, used to select one of the builtin
shell specs;
.Ar sh ,
.Ar ksh ,
and
.Ar csh .
.It Ar path
Specifies the path to the shell.
.It Ar hasErrCtl
Indicates whether the shell supports exit on error.
.It Ar check
The command to turn on error checking.
.It Ar ignore
The command to disable error checking.
.It Ar echo
The command to turn on echoing of commands executed.
.It Ar quiet
The command to turn off echoing of commands executed.
.It Ar filter
The output to filter after issuing the
.Ar quiet
command.
It is typically identical to
.Ar quiet .
.It Ar errFlag
The flag to pass the shell to enable error checking.
.It Ar echoFlag
The flag to pass the shell to enable command echoing.
.It Ar newline
The string literal to pass the shell that results in a single newline
character when used outside of any quoting characters.
.El
Example:
.Bd -literal
\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
	check="set \-e" ignore="set +e" \e
	echo="set \-v" quiet="set +v" filter="set +v" \e
	echoFlag=v errFlag=e newline="'\en'"
.Ed
.It Ic .SILENT
Apply the
.Ic .SILENT
attribute to any specified sources.
If no sources are specified, the
.Ic .SILENT
attribute is applied to every
command in the file.
.It Ic .STALE
This target gets run when a dependency file contains stale entries, having
.Va .ALLSRC
set to the name of that dependency file.
.It Ic .SUFFIXES
Each source specifies a suffix to
.Nm .
If no sources are specified, any previously specified suffixes are deleted.
It allows the creation of suffix-transformation rules.
.Pp
Example:
.Bd -literal
\&.SUFFIXES: .o
\&.c.o:
	cc \-o ${.TARGET} \-c ${.IMPSRC}
.Ed
.El
.Sh ENVIRONMENT
.Nm
uses the following environment variables, if they exist:
.Ev MACHINE ,
.Ev MACHINE_ARCH ,
.Ev MAKE ,
.Ev MAKEFLAGS ,
.Ev MAKEOBJDIR ,
.Ev MAKEOBJDIRPREFIX ,
.Ev MAKESYSPATH ,
.Ev PWD ,
and
.Ev TMPDIR .
.Pp
.Ev MAKEOBJDIRPREFIX
and
.Ev MAKEOBJDIR
may only be set in the environment or on the command line to
.Nm
and not as makefile variables;
see the description of
.Ql Va .OBJDIR
for more details.
.Sh FILES
.Bl -tag -width /usr/share/mk -compact
.It .depend
list of dependencies
.It Makefile
list of dependencies
.It makefile
list of dependencies
.It sys.mk
system makefile
.It /usr/share/mk
system makefile directory
.El
.Sh COMPATIBILITY
The basic make syntax is compatible between different versions of make,
however the special variables, variable modifiers and conditionals are not.
.Pp
The way that parallel makes are scheduled changed in
.Nx 4.0
so that .ORDER and .WAIT apply recursively to the dependent nodes.
The algorithms used may change again in the future.
.Pp
The way that .for loop variables are substituted changed after
.Nx 5.0
so that they still appear to be variable expansions.
In particular this stops them being treated as syntax, and removes some
obscure problems using them in .if statements.
.Sh SEE ALSO
.Xr mkdep 1
.Sh HISTORY
A
.Nm
command appeared in
.At v7 .
This
.Nm
implementation is based on Adam De Boor's pmake program which was written
for Sprite at Berkeley.
It was designed to be a parallel distributed make running jobs on different
machines using a daemon called
.Dq customs .
.Pp
Historically the target/dependency
.Dq FRC
has been used to FoRCe rebuilding (since the target/dependency
does not exist... unless someone creates an
.Dq FRC
file).
.Sh BUGS
The
.Nm
syntax is difficult to parse without actually acting of the data.
For instance finding the end of a variable use should involve scanning each
the modifiers using the correct terminator for each field.
In many places
.Nm
just counts {} and () in order to find the end of a variable expansion.
.Pp
There is no way of escaping a space character in a filename.