summaryrefslogtreecommitdiffstats
path: root/mandoc.1
blob: ccf39b486fad127b886d78fdef10ea13affca928 (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
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
.\" $Id$
.\"
.\" Copyright (c) 2012, 2014-2022 Ingo Schwarze <schwarze@openbsd.org>
.\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate$
.Dt MANDOC 1
.Os
.Sh NAME
.Nm mandoc
.Nd format manual pages
.Sh SYNOPSIS
.Nm mandoc
.Op Fl ac
.Op Fl I Cm os Ns = Ns Ar name
.Op Fl K Ar encoding
.Op Fl mdoc | man
.Op Fl O Ar options
.Op Fl T Ar output
.Op Fl W Ar level
.Op Ar
.Sh DESCRIPTION
The
.Nm
utility formats manual pages for display.
.Pp
By default,
.Nm
reads
.Xr mdoc 7
or
.Xr man 7
text from stdin and produces
.Fl T Cm locale
output.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl a
If the standard output is a terminal device and
.Fl c
is not specified, use
.Xr less 1
to paginate the output, just like
.Xr man 1
would.
.It Fl c
Copy the formatted manual pages to the standard output without using
.Xr less 1
to paginate them.
This is the default.
It can be specified to override
.Fl a .
.It Fl I Cm os Ns = Ns Ar name
Override the default operating system
.Ar name
for the
.Xr mdoc 7
.Ic \&Os
and for the
.Xr man 7
.Ic \&TH
macro.
.It Fl K Ar encoding
Specify the input encoding.
The supported
.Ar encoding
arguments are
.Cm us-ascii ,
.Cm iso-8859-1 ,
and
.Cm utf-8 .
If not specified, autodetection uses the first match in the following
list:
.Bl -enum
.It
If the first three bytes of the input file are the UTF-8 byte order
mark (BOM, 0xefbbbf), input is interpreted as
.Cm utf-8 .
.It
If the first or second line of the input file matches the
.Sy emacs
mode line format
.Pp
.D1 .\e" -*- Oo ...; Oc coding: Ar encoding ; No -*-
.Pp
then input is interpreted according to
.Ar encoding .
.It
If the first non-ASCII byte in the file introduces a valid UTF-8
sequence, input is interpreted as
.Cm utf-8 .
.It
Otherwise, input is interpreted as
.Cm iso-8859-1 .
.El
.It Fl mdoc | man
With
.Fl mdoc ,
all input files are interpreted as
.Xr mdoc 7 .
With
.Fl man ,
all input files are interpreted as
.Xr man 7 .
By default, the input language is automatically detected for each file:
if the first macro is
.Ic \&Dd
or
.Ic \&Dt ,
the
.Xr mdoc 7
parser is used; otherwise, the
.Xr man 7
parser is used.
With other arguments,
.Fl m
is silently ignored.
.It Fl O Ar options
Comma-separated output options.
See the descriptions of the individual output formats for supported
.Ar options .
.It Fl T Ar output
Select the output format.
Supported values for the
.Ar output
argument are
.Cm ascii ,
.Cm html ,
the default of
.Cm locale ,
.Cm man ,
.Cm markdown ,
.Cm pdf ,
.Cm ps ,
.Cm tree ,
and
.Cm utf8 .
.Pp
The special
.Fl T Cm lint
mode only parses the input and produces no output.
It implies
.Fl W Cm all
and redirects parser messages, which usually appear on standard
error output, to standard output.
.It Fl W Ar level
Specify the minimum message
.Ar level
to be reported on the standard error output and to affect the exit status.
The
.Ar level
can be
.Cm base ,
.Cm style ,
.Cm warning ,
.Cm error ,
or
.Cm unsupp .
The
.Cm base
level automatically derives the operating system from the contents of the
.Ic \&Os
macro, from the
.Fl Ios
command line option, or from the
.Xr uname 3
return value.
The levels
.Cm openbsd
and
.Cm netbsd
are variants of
.Cm base
that bypass autodetection and request validation of base system
conventions for a particular operating system.
The level
.Cm all
is an alias for
.Cm base .
By default,
.Nm
is silent.
See
.Sx EXIT STATUS
and
.Sx DIAGNOSTICS
for details.
.Pp
The special option
.Fl W Cm stop
tells
.Nm
to exit after parsing a file that causes warnings or errors of at least
the requested level.
No formatted output will be produced from that file.
If both a
.Ar level
and
.Cm stop
are requested, they can be joined with a comma, for example
.Fl W Cm error , Ns Cm stop .
.It Ar file
Read from the given input file.
If multiple files are specified, they are processed in the given order.
If unspecified,
.Nm
reads from standard input.
.El
.Pp
The options
.Fl fhklw
are also supported and are documented in
.Xr man 1 .
In
.Fl f
and
.Fl k
mode,
.Nm
also supports the options
.Fl CMmOSs
described in the
.Xr apropos 1
manual.
The options
.Fl fkl
are mutually exclusive and override each other.
.Ss ASCII Output
Use
.Fl T Cm ascii
to force text output in 7-bit ASCII character encoding documented in the
.Xr ascii 7
manual page, ignoring the
.Xr locale 1
set in the environment.
.Pp
Font styles are applied by using back-spaced encoding such that an
underlined character
.Sq c
is rendered as
.Sq _ Ns \e[bs] Ns c ,
where
.Sq \e[bs]
is the back-space character number 8.
Emboldened characters are rendered as
.Sq c Ns \e[bs] Ns c .
This markup is typically converted to appropriate terminal sequences by
the pager or
.Xr ul 1 .
To remove the markup, pipe the output to
.Xr col 1
.Fl b
instead.
.Pp
The special characters documented in
.Xr mandoc_char 7
are rendered best-effort in an ASCII equivalent.
In particular, opening and closing
.Sq single quotes
are represented as characters number 0x60 and 0x27, respectively,
which agrees with all ASCII standards from 1965 to the latest
revision (2012) and which matches the traditional way in which
.Xr roff 7
formatters represent single quotes in ASCII output.
This correct ASCII rendering may look strange with modern
Unicode-compatible fonts because contrary to ASCII, Unicode uses
the code point U+0060 for the grave accent only, never for an opening
quote.
.Pp
The following
.Fl O
arguments are accepted:
.Bl -tag -width Ds
.It Cm indent Ns = Ns Ar indent
The left margin for normal text is set to
.Ar indent
blank characters instead of the default of five for
.Xr mdoc 7
and seven for
.Xr man 7 .
Increasing this is not recommended; it may result in degraded formatting,
for example overfull lines or ugly line breaks.
When output is to a pager on a terminal that is less than 66 columns
wide, the default is reduced to three columns.
.It Cm mdoc
Format
.Xr man 7
input files in
.Xr mdoc 7
output style.
This prints the operating system name rather than the page title
on the right side of the footer line, and it implies
.Fl O Cm indent Ns =5 .
One useful application is for checking that
.Fl T Cm man
output formats in the same way as the
.Xr mdoc 7
source it was generated from.
.It Cm tag Ns Op = Ns Ar term
If the formatted manual page is opened in a pager,
go to the definition of the
.Ar term
rather than showing the manual page from the beginning.
If no
.Ar term
is specified, reuse the first command line argument that is not a
.Ar section
number.
If that argument is in
.Xr apropos 1
.Ar key Ns = Ns Ar val
format, only the
.Ar val
is used rather than the argument as a whole.
This is useful for commands like
.Ql man -akO tag Ic=ulimit
to search for a keyword and jump right to its definition
in the matching manual pages.
.It Cm width Ns = Ns Ar width
The output width is set to
.Ar width
instead of the default of 78.
When output is to a pager on a terminal that is less than 79 columns
wide, the default is reduced to one less than the terminal width.
In any case, lines that are output in literal mode are never wrapped
and may exceed the output width.
.El
.Ss HTML Output
Output produced by
.Fl T Cm html
conforms to HTML5 using optional self-closing tags.
Equations rendered from
.Xr eqn 7
blocks use MathML.
.Pp
The file
.Pa /usr/share/misc/mandoc.css
documents style-sheet classes available for customising output.
If a style-sheet is not specified with
.Fl O Cm style ,
.Fl T Cm html
defaults to simple output (via an embedded style-sheet)
readable in any graphical or text-based web
browser.
.Pp
Non-ASCII characters are rendered
as hexadecimal Unicode character references.
.Pp
The following
.Fl O
arguments are accepted:
.Bl -tag -width Ds
.It Cm fragment
Omit the <!DOCTYPE> declaration and the <html>, <head>, and <body>
elements and only emit the subtree below the <body> element.
The
.Cm style
argument will be ignored.
This is useful when embedding manual content within existing documents.
.It Cm includes Ns = Ns Ar fmt
The string
.Ar fmt ,
for example,
.Ar ../src/%I.html ,
is used as a template for linked header files (usually via the
.Ic \&In
macro).
Instances of
.Sq \&%I
are replaced with the include filename.
The default is not to present a
hyperlink.
.It Cm man Ns = Ns Ar fmt Ns Op ; Ns Ar fmt
The string
.Ar fmt ,
for example,
.Ar ../html%S/%N.%S.html ,
is used as a template for linked manuals (usually via the
.Ic \&Xr
macro).
Instances of
.Sq \&%N
and
.Sq %S
are replaced with the linked manual's name and section, respectively.
If no section is included, section 1 is assumed.
The default is not to
present a hyperlink.
If two formats are given and a file
.Ar %N.%S
exists in the current directory, the first format is used;
otherwise, the second format is used.
.It Cm style Ns = Ns Ar style.css
The file
.Ar style.css
is used for an external style-sheet.
This must be a valid absolute or
relative URI.
.It Cm tag Ns Op = Ns Ar term
Same syntax and semantics as for
.Sx ASCII Output .
This is implemented by passing a
.Ic file://
URI ending in a fragment identifier to the pager
rather than passing merely a file name.
When using this argument, use a pager supporting such URIs, for example
.Bd -literal -offset 3n
MANPAGER='lynx -force_html' man -T html -O tag=MANPAGER man
MANPAGER='w3m -T text/html' man -T html -O tag=toc mandoc
.Ed
.Pp
Consequently, for HTML output, this argument does not work with
.Xr more 1
or
.Xr less 1 .
For example,
.Ql MANPAGER=less man -T html -O tag=toc mandoc
does not work because
.Xr less 1
does not support
.Ic file://
URIs.
.It Cm toc
If an input file contains at least two non-standard sections,
print a table of contents near the beginning of the output.
.El
.Ss Locale Output
By default,
.Nm
automatically selects UTF-8 or ASCII output according to the current
.Xr locale 1 .
If any of the environment variables
.Ev LC_ALL ,
.Ev LC_CTYPE ,
or
.Ev LANG
are set and the first one that is set
selects the UTF-8 character encoding, it produces
.Sx UTF-8 Output ;
otherwise, it falls back to
.Sx ASCII Output .
This output mode can also be selected explicitly with
.Fl T Cm locale .
.Ss Man Output
Use
.Fl T Cm man
to translate
.Xr mdoc 7
input into
.Xr man 7
output format.
This is useful for distributing manual sources to legacy systems
lacking
.Xr mdoc 7
formatters.
Embedded
.Xr eqn 7
and
.Xr tbl 7
code is not supported.
.Pp
If the input format of a file is
.Xr man 7 ,
the input is copied to the output.
The parser is also run, and as usual, the
.Fl W
level controls which
.Sx DIAGNOSTICS
are displayed before copying the input to the output.
.Ss Markdown Output
Use
.Fl T Cm markdown
to translate
.Xr mdoc 7
input to the markdown format conforming to
.Lk https://daringfireball.net/projects/markdown/syntax.text\
 "John Gruber's 2004 specification" .
The output also almost conforms to the
.Lk https://commonmark.org/ CommonMark
specification.
.Pp
The character set used for the markdown output is ASCII.
Non-ASCII characters are encoded as HTML entities.
Since that is not possible in literal font contexts, because these
are rendered as code spans and code blocks in the markdown output,
non-ASCII characters are transliterated to ASCII approximations in
these contexts.
.Pp
Markdown is a very weak markup language, so all semantic markup is
lost, and even part of the presentational markup may be lost.
Do not use this as an intermediate step in converting to HTML;
instead, use
.Fl T Cm html
directly.
.Pp
The
.Xr man 7 ,
.Xr tbl 7 ,
and
.Xr eqn 7
input languages are not supported by
.Fl T Cm markdown
output mode.
.Ss PDF Output
PDF-1.1 output may be generated by
.Fl T Cm pdf .
See
.Sx PostScript Output
for
.Fl O
arguments and defaults.
.Ss PostScript Output
PostScript
.Qq Adobe-3.0
Level-2 pages may be generated by
.Fl T Cm ps .
Output pages default to letter sized and are rendered in the Times font
family, 11-point.
Margins are calculated as 1/9 the page length and width.
Line-height is 1.4m.
.Pp
Special characters are rendered as in
.Sx ASCII Output .
.Pp
The following
.Fl O
arguments are accepted:
.Bl -tag -width Ds
.It Cm paper Ns = Ns Ar name
The paper size
.Ar name
may be one of
.Ar a3 ,
.Ar a4 ,
.Ar a5 ,
.Ar legal ,
or
.Ar letter .
You may also manually specify dimensions as
.Ar NNxNN ,
width by height in millimetres.
If an unknown value is encountered,
.Ar letter
is used.
.El
.Ss UTF-8 Output
Use
.Fl T Cm utf8
to force text output in UTF-8 multi-byte character encoding,
ignoring the
.Xr locale 1
settings in the environment.
See
.Sx ASCII Output
regarding font styles and
.Fl O
arguments.
.Pp
On operating systems lacking locale or wide character support, and
on those where the internal character representation is not UCS-4,
.Nm
always falls back to
.Sx ASCII Output .
.Ss Syntax tree output
Use
.Fl T Cm tree
to show a human readable representation of the syntax tree.
It is useful for debugging the source code of manual pages.
The exact format is subject to change, so don't write parsers for it.
.Pp
The first paragraph shows meta data found in the
.Xr mdoc 7
prologue, on the
.Xr man 7
.Ic \&TH
line, or the fallbacks used.
.Pp
In the tree dump, each output line shows one syntax tree node.
Child nodes are indented with respect to their parent node.
The columns are:
.Pp
.Bl -enum -compact
.It
For macro nodes, the macro name; for text and
.Xr tbl 7
nodes, the content.
There is a special format for
.Xr eqn 7
nodes.
.It
Node type (text, elem, block, head, body, body-end, tail, tbl, eqn).
.It
Flags:
.Bl -dash -compact
.It
An opening parenthesis if the node is an opening delimiter.
.It
An asterisk if the node starts a new input line.
.It
The input line number (starting at one).
.It
A colon.
.It
The input column number (starting at one).
.It
A closing parenthesis if the node is a closing delimiter.
.It
A full stop if the node ends a sentence.
.It
BROKEN if the node is a block broken by another block.
.It
NOSRC if the node is not in the input file,
but automatically generated from macros.
.It
NOPRT if the node is not supposed to generate output
for any output format.
.El
.El
.Pp
The following
.Fl O
argument is accepted:
.Bl -tag -width Ds
.It Cm noval
Skip validation and show the unvalidated syntax tree.
This can help to find out whether a given behaviour is caused by
the parser or by the validator.
Meta data is not available in this case.
.El
.Sh ENVIRONMENT
.Bl -tag -width MANPAGER
.It Ev LC_CTYPE
The character encoding
.Xr locale 1 .
When
.Sx Locale Output
is selected, it decides whether to use ASCII or UTF-8 output format.
It never affects the interpretation of input files.
.It Ev MANPAGER
Any non-empty value of the environment variable
.Ev MANPAGER
is used instead of the standard pagination program,
.Xr less 1 ;
see
.Xr man 1
for details.
Only used if
.Fl a
or
.Fl l
is specified.
.It Ev PAGER
Specifies the pagination program to use when
.Ev MANPAGER
is not defined.
If neither PAGER nor MANPAGER is defined,
.Xr less 1
is used.
Only used if
.Fl a
or
.Fl l
is specified.
.El
.Sh EXIT STATUS
The
.Nm
utility exits with one of the following values, controlled by the message
.Ar level
associated with the
.Fl W
option:
.Pp
.Bl -tag -width Ds -compact
.It 0
No base system convention violations, style suggestions, warnings,
or errors occurred, or those that did were ignored because they
were lower than the requested
.Ar level .
.It 1
At least one base system convention violation or style suggestion
occurred, but no warning or error, and
.Fl W Cm base
or
.Fl W Cm style
was specified.
.It 2
At least one warning occurred, but no error, and
.Fl W Cm warning
or a lower
.Ar level
was requested.
.It 3
At least one parsing error occurred,
but no unsupported feature was encountered, and
.Fl W Cm error
or a lower
.Ar level
was requested.
.It 4
At least one unsupported feature was encountered, and
.Fl W Cm unsupp
or a lower
.Ar level
was requested.
.It 5
Invalid command line arguments were specified.
No input files have been read.
.It 6
An operating system error occurred, for example exhaustion
of memory, file descriptors, or process table entries.
Such errors may cause
.Nm
to exit at once, possibly in the middle of parsing or formatting a file.
.El
.Pp
Note that selecting
.Fl T Cm lint
output mode implies
.Fl W Cm all .
.Sh EXAMPLES
To page manuals to the terminal:
.Pp
.Dl $ mandoc -a mandoc.1 man.1 apropos.1 makewhatis.8
.Pp
To produce HTML manuals with
.Pa /usr/share/misc/mandoc.css
as the style-sheet:
.Pp
.Dl $ mandoc \-T html -O style=/usr/share/misc/mandoc.css mdoc.7 > mdoc.7.html
.Pp
To check over a large set of manuals:
.Pp
.Dl $ mandoc \-T lint \(gafind /usr/src -name \e*\e.[1-9]\(ga
.Pp
To produce a series of PostScript manuals for A4 paper:
.Pp
.Dl $ mandoc \-T ps \-O paper=a4 mdoc.7 man.7 > manuals.ps
.Pp
Convert a modern
.Xr mdoc 7
manual to the older
.Xr man 7
format, for use on systems lacking an
.Xr mdoc 7
parser:
.Pp
.Dl $ mandoc \-T man foo.mdoc > foo.man
.Sh DIAGNOSTICS
Messages displayed by
.Nm
follow this format:
.Bd -ragged -offset indent
.Nm :
.Ar file : Ns Ar line : Ns Ar column : level : message : macro arguments
.Pq Ar os
.Ed
.Pp
The first three fields identify the
.Ar file
name,
.Ar line
number, and
.Ar column
number of the input file where the message was triggered.
The line and column numbers start at 1.
Both are omitted for messages referring to an input file as a whole.
All
.Ar level
and
.Ar message
strings are explained below.
The name of the
.Ar macro
triggering the message and its
.Ar arguments
are omitted where meaningless.
The
.Ar os
operating system specifier is omitted for messages that are relevant
for all operating systems.
Fatal messages about invalid command line arguments
or operating system errors, for example when memory is exhausted,
may also omit the
.Ar file
and
.Ar level
fields.
.Pp
Message levels have the following meanings:
.Bl -tag -width "warning"
.It Cm syserr
An operating system error occurred.
There isn't necessarily anything wrong with the input files.
Output may all the same be missing or incomplete.
.It Cm badarg
Invalid command line arguments were specified.
No input files have been read and no output is produced.
.It Cm unsupp
An input file uses unsupported low-level
.Xr roff 7
features.
The output may be incomplete and/or misformatted,
so using GNU troff instead of
.Nm
to process the file may be preferable.
.It Cm error
Indicates a risk of information loss or severe misformatting,
in most cases caused by serious syntax errors.
.It Cm warning
Indicates a risk that the information shown or its formatting
may mismatch the author's intent in minor ways.
Additionally, syntax errors are classified at least as warnings,
even if they do not usually cause misformatting.
.It Cm style
An input file uses dubious or discouraged style.
This is not a complaint about the syntax, and probably neither
formatting nor portability are in danger.
While great care is taken to avoid false positives on the higher
message levels, the
.Cm style
level tries to reduce the probability that issues go unnoticed,
so it may occasionally issue bogus suggestions.
Use your judgement to decide whether any particular
.Cm style
suggestion really justifies a change to the input file.
.It Cm base
A convention used in the base system of a specific operating system
is not adhered to.
These are not markup mistakes, and neither the quality of formatting
nor portability are in danger.
Messages of the
.Cm base
level are printed with the more intuitive
.Cm style
.Ar level
tag.
.El
.Pp
Messages of the
.Cm base ,
.Cm style ,
.Cm warning ,
.Cm error ,
and
.Cm unsupp
levels are hidden unless their level, or a lower level, is requested using a
.Fl W
option or
.Fl T Cm lint
output mode.
.Pp
As indicated below, all
.Cm base
and some
.Cm style
checks are only performed if a specific operating system name occurs
in the arguments of the
.Fl W
command line option, of the
.Ic \&Os
macro, of the
.Fl Ios
command line option, or, if neither are present, in the return value
of the
.Xr uname 3
function.
.Ss Conventions for base system manuals
.Bl -ohang
.It Sy "Mdocdate found"
.Pq mdoc , Nx
The
.Ic \&Dd
macro uses CVS
.Ic Mdocdate
keyword substitution, which is not supported by the
.Nx
base system.
Consider using the conventional
.Dq "Month dd, yyyy"
format instead.
.It Sy "Mdocdate missing"
.Pq mdoc , Ox
The
.Ic \&Dd
macro does not use CVS
.Ic Mdocdate
keyword substitution, but using it is conventionally expected in the
.Ox
base system.
.It Sy "unknown architecture"
.Pq mdoc , Ox , Nx
The third argument of the
.Ic \&Dt
macro does not match any of the architectures this operating system
is running on.
.It Sy "operating system explicitly specified"
.Pq mdoc , Ox , Nx
The
.Ic \&Os
macro has an argument.
In the base system, it is conventionally left blank.
.It Sy "RCS id missing"
.Pq Ox , Nx
The manual page lacks the comment line with the RCS identifier
generated by CVS
.Ic OpenBSD
or
.Ic NetBSD
keyword substitution as conventionally used in these operating systems.
.El
.Ss Style suggestions
.Bl -ohang
.It Sy "legacy man(7) date format"
.Pq mdoc
The
.Ic \&Dd
macro uses the legacy
.Xr man 7
date format
.Dq yyyy-dd-mm .
Consider using the conventional
.Xr mdoc 7
date format
.Dq "Month dd, yyyy"
instead.
.It Sy "normalizing date format to" : No ...
.Pq mdoc , man
The
.Ic \&Dd
or
.Ic \&TH
macro provides an abbreviated month name or a day number with a
leading zero.
In the formatted output, the month name is written out in full
and the leading zero is omitted.
.It Sy "lower case character in document title"
.Pq mdoc , man
The title is still used as given in the
.Ic \&Dt
or
.Ic \&TH
macro.
.It Sy "duplicate RCS id"
A single manual page contains two copies of the RCS identifier for
the same operating system.
Consider deleting the later instance and moving the first one up
to the top of the page.
.It Sy "possible typo in section name"
.Pq mdoc
Fuzzy string matching revealed that the argument of an
.Ic \&Sh
macro is similar, but not identical to a standard section name.
.It Sy "unterminated quoted argument"
.Pq roff
Macro arguments can be enclosed in double quote characters
such that space characters and macro names contained in the quoted
argument need not be escaped.
The closing quote of the last argument of a macro can be omitted.
However, omitting it is not recommended because it makes the code
harder to read.
.It Sy "useless macro"
.Pq mdoc
A
.Ic \&Bt ,
.Ic \&Tn ,
or
.Ic \&Ud
macro was found.
Simply delete it: it serves no useful purpose.
.It Sy "consider using OS macro"
.Pq mdoc
A string was found in plain text or in a
.Ic \&Bx
macro that could be represented using
.Ic \&Ox ,
.Ic \&Nx ,
.Ic \&Fx ,
or
.Ic \&Dx .
.It Sy "errnos out of order"
.Pq mdoc, Nx
The
.Ic \&Er
items in a
.Ic \&Bl
list are not in alphabetical order.
.It Sy "duplicate errno"
.Pq mdoc, Nx
A
.Ic \&Bl
list contains two consecutive
.Ic \&It
entries describing the same
.Ic \&Er
number.
.It Sy "referenced manual not found"
.Pq mdoc
An
.Ic \&Xr
macro references a manual page that was not found.
When running with
.Fl W Cm base ,
the search is restricted to the base system, by default to
.Pa /usr/share/man : Ns Pa /usr/X11R6/man .
This path can be configured at compile time using the
.Dv MANPATH_BASE
preprocessor macro.
When running with
.Fl W Cm style ,
the search is done along the full search path as described in the
.Xr man 1
manual page, respecting the
.Fl m
and
.Fl M
command line options, the
.Ev MANPATH
environment variable, the
.Xr man.conf 5
file and falling back to the default of
.Pa /usr/share/man : Ns Pa /usr/X11R6/man : Ns Pa /usr/local/man ,
also configurable at compile time using the
.Dv MANPATH_DEFAULT
preprocessor macro.
.It Sy "trailing delimiter"
.Pq mdoc
The last argument of an
.Ic \&Ex , \&Fo , \&Nd , \&Nm , \&Os , \&Sh , \&Ss , \&St ,
or
.Ic \&Sx
macro ends with a trailing delimiter.
This is usually bad style and often indicates typos.
Most likely, the delimiter can be removed.
.It Sy "no blank before trailing delimiter"
.Pq mdoc
The last argument of a macro that supports trailing delimiter
arguments is longer than one byte and ends with a trailing delimiter.
Consider inserting a blank such that the delimiter becomes a separate
argument, thus moving it out of the scope of the macro.
.It Sy "fill mode already enabled, skipping"
.Pq man
A
.Ic \&fi
request occurs even though the document is still in fill mode,
or already switched back to fill mode.
It has no effect.
.It Sy "fill mode already disabled, skipping"
.Pq man
An
.Ic \&nf
request occurs even though the document already switched to no-fill mode
and did not switch back to fill mode yet.
It has no effect.
.It Sy "input text line longer than 80 bytes"
Consider breaking the input text line
at one of the blank characters before column 80.
.It Sy "verbatim \(dq--\(dq, maybe consider using \e(em"
.Pq mdoc
Even though the ASCII output device renders an em-dash as
.Qq \-\- ,
that is not a good way to write it in an input file
because it renders poorly on all other output devices.
.It Sy "function name without markup"
.Pq mdoc
A word followed by an empty pair of parentheses occurs on a text line.
Consider using an
.Ic \&Fn
or
.Ic \&Xr
macro.
.It Sy "whitespace at end of input line"
.Pq mdoc , man , roff
Whitespace at the end of input lines is almost never semantically
significant \(em but in the odd case where it might be, it is
extremely confusing when reviewing and maintaining documents.
.It Sy "bad comment style"
.Pq roff
Comment lines start with a dot, a backslash, and a double-quote character.
The
.Nm
utility treats the line as a comment line even without the backslash,
but leaving out the backslash might not be portable.
.El
.Ss Warnings related to the document prologue
.Bl -ohang
.It Sy "missing manual title, using UNTITLED"
.Pq mdoc
A
.Ic \&Dt
macro has no arguments, or there is no
.Ic \&Dt
macro before the first non-prologue macro.
.It Sy "missing manual title, using \(dq\(dq"
.Pq man
There is no
.Ic \&TH
macro, or it has no arguments.
.It Sy "missing manual section, using \(dq\(dq"
.Pq mdoc , man
A
.Ic \&Dt
or
.Ic \&TH
macro lacks the mandatory section argument.
.It Sy "unknown manual section"
.Pq mdoc
The section number in a
.Ic \&Dt
line is invalid, but still used.
.It Sy "filename/section mismatch"
.Pq mdoc , man
The name of the input file being processed is known and its file
name extension starts with a non-zero digit, but the
.Ic \&Dt
or
.Ic \&TH
macro contains a
.Ar section
argument that starts with a different non-zero digit.
The
.Ar section
argument is used as provided anyway.
Consider checking whether the file name or the argument need a correction.
.It Sy "missing date, using \(dq\(dq"
.Pq mdoc, man
The document was parsed as
.Xr mdoc 7
and it has no
.Ic \&Dd
macro, or the
.Ic \&Dd
macro has no arguments or only empty arguments;
or the document was parsed as
.Xr man 7
and it has no
.Ic \&TH
macro, or the
.Ic \&TH
macro has less than three arguments or its third argument is empty.
.It Sy "cannot parse date, using it verbatim"
.Pq mdoc , man
The date given in a
.Ic \&Dd
or
.Ic \&TH
macro does not follow the conventional format.
.It Sy "date in the future, using it anyway"
.Pq mdoc , man
The date given in a
.Ic \&Dd
or
.Ic \&TH
macro is more than a day ahead of the current system
.Xr time 3 .
.It Sy "missing Os macro, using \(dq\(dq"
.Pq mdoc
The default or current system is not shown in this case.
.It Sy "late prologue macro"
.Pq mdoc
A
.Ic \&Dd
or
.Ic \&Os
macro occurs after some non-prologue macro, but still takes effect.
.It Sy "prologue macros out of order"
.Pq mdoc
The prologue macros are not given in the conventional order
.Ic \&Dd ,
.Ic \&Dt ,
.Ic \&Os .
All three macros are used even when given in another order.
.El
.Ss Warnings regarding document structure
.Bl -ohang
.It Sy ".so is fragile, better use ln(1)"
.Pq roff
Including files only works when the parser program runs with the correct
current working directory.
.It Sy "no document body"
.Pq mdoc , man
The document body contains neither text nor macros.
An empty document is shown, consisting only of a header and a footer line.
.It Sy "content before first section header"
.Pq mdoc , man
Some macros or text precede the first
.Ic \&Sh
or
.Ic \&SH
section header.
The offending macros and text are parsed and added to the top level
of the syntax tree, outside any section block.
.It Sy "first section is not NAME"
.Pq mdoc
The argument of the first
.Ic \&Sh
macro is not
.Sq NAME .
This may confuse
.Xr makewhatis 8
and
.Xr apropos 1 .
.It Sy "NAME section without Nm before Nd"
.Pq mdoc
The NAME section does not contain any
.Ic \&Nm
child macro before the first
.Ic \&Nd
macro.
.It Sy "NAME section without description"
.Pq mdoc
The NAME section lacks the mandatory
.Ic \&Nd
child macro.
.It Sy "description not at the end of NAME"
.Pq mdoc
The NAME section does contain an
.Ic \&Nd
child macro, but other content follows it.
.It Sy "bad NAME section content"
.Pq mdoc
The NAME section contains plain text or macros other than
.Ic \&Nm
and
.Ic \&Nd .
.It Sy "missing comma before name"
.Pq mdoc
The NAME section contains an
.Ic \&Nm
macro that is neither the first one nor preceded by a comma.
.It Sy "missing description line, using \(dq\(dq"
.Pq mdoc
The
.Ic \&Nd
macro lacks the required argument.
The title line of the manual will end after the dash.
.It Sy "description line outside NAME section"
.Pq mdoc
An
.Ic \&Nd
macro appears outside the NAME section.
The arguments are printed anyway and the following text is used for
.Xr apropos 1 ,
but none of that behaviour is portable.
.It Sy "sections out of conventional order"
.Pq mdoc
A standard section occurs after another section it usually precedes.
All section titles are used as given,
and the order of sections is not changed.
.It Sy "duplicate section title"
.Pq mdoc
The same standard section title occurs more than once.
.It Sy "unexpected section"
.Pq mdoc
A standard section header occurs in a section of the manual
where it normally isn't useful.
.It Sy "cross reference to self"
.Pq mdoc
An
.Ic \&Xr
macro refers to a name and section matching the section of the present
manual page and a name mentioned in an
.Ic \&Nm
macro in the NAME or SYNOPSIS section, or in an
.Ic \&Fn
or
.Ic \&Fo
macro in the SYNOPSIS.
Consider using
.Ic \&Nm
or
.Ic \&Fn
instead of
.Ic \&Xr .
.It Sy "unusual Xr order"
.Pq mdoc
In the SEE ALSO section, an
.Ic \&Xr
macro with a lower section number follows one with a higher number,
or two
.Ic \&Xr
macros referring to the same section are out of alphabetical order.
.It Sy "unusual Xr punctuation"
.Pq mdoc
In the SEE ALSO section, punctuation between two
.Ic \&Xr
macros differs from a single comma, or there is trailing punctuation
after the last
.Ic \&Xr
macro.
.It Sy "AUTHORS section without An macro"
.Pq mdoc
An AUTHORS sections contains no
.Ic \&An
macros, or only empty ones.
Probably, there are author names lacking markup.
.El
.Ss "Warnings related to macros and nesting"
.Bl -ohang
.It Sy "obsolete macro"
.Pq mdoc
See the
.Xr mdoc 7
manual for replacements.
.It Sy "macro neither callable nor escaped"
.Pq mdoc
The name of a macro that is not callable appears on a macro line.
It is printed verbatim.
If the intention is to call it, move it to its own input line;
otherwise, escape it by prepending
.Sq \e& .
.It Sy "skipping paragraph macro"
In
.Xr mdoc 7
documents, this happens
.Bl -dash -compact
.It
at the beginning and end of sections and subsections
.It
right before non-compact lists and displays
.It
at the end of items in non-column, non-compact lists
.It
and for multiple consecutive paragraph macros.
.El
In
.Xr man 7
documents, it happens
.Bl -dash -compact
.It
for empty
.Ic \&P ,
.Ic \&PP ,
and
.Ic \&LP
macros
.It
for
.Ic \&IP
macros having neither head nor body arguments
.It
for
.Ic \&br
or
.Ic \&sp
right after
.Ic \&SH
or
.Ic \&SS
.El
.It Sy "moving paragraph macro out of list"
.Pq mdoc
A list item in a
.Ic \&Bl
list contains a trailing paragraph macro.
The paragraph macro is moved after the end of the list.
.It Sy "skipping no-space macro"
.Pq mdoc
An input line begins with an
.Ic \&Ns
macro, or the next argument after an
.Ic \&Ns
macro is an isolated closing delimiter.
The macro is ignored.
.It Sy "blocks badly nested"
.Pq mdoc
If two blocks intersect, one should completely contain the other.
Otherwise, rendered output is likely to look strange in any output
format, and rendering in SGML-based output formats is likely to be
outright wrong because such languages do not support badly nested
blocks at all.
Typical examples of badly nested blocks are
.Qq Ic \&Ao \&Bo \&Ac \&Bc
and
.Qq Ic \&Ao \&Bq \&Ac .
In these examples,
.Ic \&Ac
breaks
.Ic \&Bo
and
.Ic \&Bq ,
respectively.
.It Sy "nested displays are not portable"
.Pq mdoc
A
.Ic \&Bd ,
.Ic \&D1 ,
or
.Ic \&Dl
display occurs nested inside another
.Ic \&Bd
display.
This works with
.Nm ,
but fails with most other implementations.
.It Sy "moving content out of list"
.Pq mdoc
A
.Ic \&Bl
list block contains text or macros before the first
.Ic \&It
macro.
The offending children are moved before the beginning of the list.
.It Sy "first macro on line"
Inside a
.Ic \&Bl Fl column
list, a
.Ic \&Ta
macro occurs as the first macro on a line, which is not portable.
.It Sy "line scope broken"
.Pq man
While parsing the next-line scope of the previous macro,
another macro is found that prematurely terminates the previous one.
The previous, interrupted macro is deleted from the parse tree.
.El
.Ss "Warnings related to missing arguments"
.Bl -ohang
.It Sy "skipping empty request"
.Pq roff , eqn
The macro name is missing from a macro definition request,
or an
.Xr eqn 7
control statement or operation keyword lacks its required argument.
.It Sy "conditional request controls empty scope"
.Pq roff
A conditional request is only useful if any of the following
follows it on the same logical input line:
.Bl -dash -compact
.It
The
.Sq \e{
keyword to open a multi-line scope.
.It
A request or macro or some text, resulting in a single-line scope.
.It
The immediate end of the logical line without any intervening whitespace,
resulting in next-line scope.
.El
Here, a conditional request is followed by trailing whitespace only,
and there is no other content on its logical input line.
Note that it doesn't matter whether the logical input line is split
across multiple physical input lines using
.Sq \e
line continuation characters.
This is one of the rare cases
where trailing whitespace is syntactically significant.
The conditional request controls a scope containing whitespace only,
so it is unlikely to have a significant effect,
except that it may control a following
.Ic \&el
clause.
.It Sy "skipping empty macro"
.Pq mdoc
The indicated macro has no arguments and hence no effect.
.It Sy "empty block"
.Pq mdoc , man
A
.Ic \&Bd ,
.Ic \&Bk ,
.Ic \&Bl ,
.Ic \&D1 ,
.Ic \&Dl ,
or
.Ic \&RS
block contains nothing in its body and will produce no output.
.It Sy "empty argument, using 0n"
.Pq mdoc
The required width is missing after
.Ic \&Bd
or
.Ic \&Bl
.Fl offset
or
.Fl width .
.It Sy "missing display type, using -ragged"
.Pq mdoc
The
.Ic \&Bd
macro is invoked without the required display type.
.It Sy "list type is not the first argument"
.Pq mdoc
In a
.Ic \&Bl
macro, at least one other argument precedes the type argument.
The
.Nm
utility copes with any argument order, but some other
.Xr mdoc 7
implementations do not.
.It Sy "missing -width in -tag list, using 8n"
.Pq mdoc
Every
.Ic \&Bl
macro having the
.Fl tag
argument requires
.Fl width ,
too.
.It Sy "missing utility name, using \(dq\(dq"
.Pq mdoc
The
.Ic \&Ex Fl std
macro is called without an argument before
.Ic \&Nm
has first been called with an argument.
.It Sy "missing function name, using \(dq\(dq"
.Pq mdoc
The
.Ic \&Fo
macro is called without an argument.
No function name is printed.
.It Sy "empty head in list item"
.Pq mdoc
In a
.Ic \&Bl
.Fl diag ,
.Fl hang ,
.Fl inset ,
.Fl ohang ,
or
.Fl tag
list, an
.Ic \&It
macro lacks the required argument.
The item head is left empty.
.It Sy "empty list item"
.Pq mdoc
In a
.Ic \&Bl
.Fl bullet ,
.Fl dash ,
.Fl enum ,
or
.Fl hyphen
list, an
.Ic \&It
block is empty.
An empty list item is shown.
.It Sy "missing argument, using next line"
.Pq mdoc
An
.Ic \&It
macro in a
.Ic \&Bd Fl column
list has no arguments.
While
.Nm
uses the text or macros of the following line, if any, for the cell,
other formatters may misformat the list.
.It Sy "missing font type, using \efR"
.Pq mdoc
A
.Ic \&Bf
macro has no argument.
It switches to the default font.
.It Sy "unknown font type, using \efR"
.Pq mdoc
The
.Ic \&Bf
argument is invalid.
The default font is used instead.
.It Sy "nothing follows prefix"
.Pq mdoc
A
.Ic \&Pf
macro has no argument, or only one argument and no macro follows
on the same input line.
This defeats its purpose; in particular, spacing is not suppressed
before the text or macros following on the next input line.
.It Sy "empty reference block"
.Pq mdoc
An
.Ic \&Rs
macro is immediately followed by an
.Ic \&Re
macro on the next input line.
Such an empty block does not produce any output.
.It Sy "missing section argument"
.Pq mdoc
An
.Ic \&Xr
macro lacks its second, section number argument.
The first argument, i.e. the name, is printed, but without subsequent
parentheses.
.It Sy "missing -std argument, adding it"
.Pq mdoc
An
.Ic \&Ex
or
.Ic \&Rv
macro lacks the required
.Fl std
argument.
The
.Nm
utility assumes
.Fl std
even when it is not specified, but other implementations may not.
.It Sy "missing option string, using \(dq\(dq"
.Pq man
The
.Ic \&OP
macro is invoked without any argument.
An empty pair of square brackets is shown.
.It Sy "missing resource identifier, using \(dq\(dq"
.Pq man
The
.Ic \&MT
or
.Ic \&UR
macro is invoked without any argument.
An empty pair of angle brackets is shown.
.It Sy "missing eqn box, using \(dq\(dq"
.Pq eqn
A diacritic mark or a binary operator is found,
but there is nothing to the left of it.
An empty box is inserted.
.El
.Ss "Warnings related to bad macro arguments"
.Bl -ohang
.It Sy "duplicate argument"
.Pq mdoc
A
.Ic \&Bd
or
.Ic \&Bl
macro has more than one
.Fl compact ,
more than one
.Fl offset ,
or more than one
.Fl width
argument.
All but the last instances of these arguments are ignored.
.It Sy "skipping duplicate argument"
.Pq mdoc
An
.Ic \&An
macro has more than one
.Fl split
or
.Fl nosplit
argument.
All but the first of these arguments are ignored.
.It Sy "skipping duplicate display type"
.Pq mdoc
A
.Ic \&Bd
macro has more than one type argument; the first one is used.
.It Sy "skipping duplicate list type"
.Pq mdoc
A
.Ic \&Bl
macro has more than one type argument; the first one is used.
.It Sy "skipping -width argument"
.Pq mdoc
A
.Ic \&Bl
.Fl column ,
.Fl diag ,
.Fl ohang ,
.Fl inset ,
or
.Fl item
list has a
.Fl width
argument.
That has no effect.
.It Sy "wrong number of cells"
In a line of a
.Ic \&Bl Fl column
list, the number of tabs or
.Ic \&Ta
macros is less than the number expected from the list header line
or exceeds the expected number by more than one.
Missing cells remain empty, and all cells exceeding the number of
columns are joined into one single cell.
.It Sy "unknown AT&T UNIX version"
.Pq mdoc
An
.Ic \&At
macro has an invalid argument.
It is used verbatim, with
.Qq "AT&T UNIX "
prefixed to it.
.It Sy "comma in function argument"
.Pq mdoc
An argument of an
.Ic \&Fa
or
.Ic \&Fn
macro contains a comma; it should probably be split into two arguments.
.It Sy "parenthesis in function name"
.Pq mdoc
The first argument of an
.Ic \&Fc
or
.Ic \&Fn
macro contains an opening or closing parenthesis; that's probably wrong,
parentheses are added automatically.
.It Sy "unknown library name"
.Pq mdoc, not on Ox
An
.Ic \&Lb
macro has an unknown name argument and will be rendered as
.Qq library Dq Ar name .
.It Sy "invalid content in Rs block"
.Pq mdoc
An
.Ic \&Rs
block contains plain text or non-% macros.
The bogus content is left in the syntax tree.
Formatting may be poor.
.It Sy "invalid Boolean argument"
.Pq mdoc
An
.Ic \&Sm
macro has an argument other than
.Cm on
or
.Cm off .
The invalid argument is moved out of the macro, which leaves the macro
empty, causing it to toggle the spacing mode.
.It Sy "argument contains two font escapes"
.Pq roff
The second argument of a
.Ic char
request contains more than one font escape sequence.
A wrong font may remain active after using the character.
.It Sy "unknown font, skipping request"
.Pq man , tbl
A
.Xr roff 7
.Ic \&ft
request or a
.Xr tbl 7
.Ic \&f
layout modifier has an unknown
.Ar font
argument.
.It Sy "ignoring distance argument"
.Pq roff
In addition to the margin character, an
.Ic \&mc
request has a second argument supposed to represent a distance, but the
.Nm
implementation of
.Ic \&mc
always ignores the second argument.
.It Sy "odd number of characters in request"
.Pq roff
A
.Ic \&tr
request contains an odd number of characters.
The last character is mapped to the blank character.
.El
.Ss "Warnings related to plain text"
.Bl -ohang
.It Sy "blank line in fill mode, using .sp"
.Pq mdoc
The meaning of blank input lines is only well-defined in non-fill mode:
In fill mode, line breaks of text input lines are not supposed to be
significant.
However, for compatibility with groff, blank lines in fill mode
are formatted like
.Ic \&sp
requests.
To request a paragraph break, use
.Ic \&Pp
instead of a blank line.
.It Sy "tab in filled text"
.Pq mdoc , man
The meaning of tab characters is only well-defined in non-fill mode:
In fill mode, whitespace is not supposed to be significant
on text input lines.
As an implementation dependent choice, tab characters on text lines
are passed through to the formatters in any case.
Given that the text before the tab character will be filled,
it is hard to predict which tab stop position the tab will advance to.
.It Sy "new sentence, new line"
.Pq mdoc
A new sentence starts in the middle of a text line.
Start it on a new input line to help formatters produce correct spacing.
.It Sy "invalid escape sequence argument"
.Pq roff
The argument of an escape sequence is of an invalid form.
Invalid escape sequences are ignored.
.It Sy "undefined escape, printing literally"
.Pq roff
In an escape sequence, the first character
right after the leading backslash is invalid.
That character is printed literally,
which is equivalent to ignoring the backslash.
.It Sy "undefined string, using \(dq\(dq"
.Pq roff
If a string is used without being defined before,
its value is implicitly set to the empty string.
However, defining strings explicitly before use
keeps the code more readable.
.El
.Ss "Warnings related to tables"
.Bl -ohang
.It Sy "tbl line starts with span"
.Pq tbl
The first cell in a table layout line is a horizontal span
.Pq Sq Cm s .
Data provided for this cell is ignored, and nothing is printed in the cell.
.It Sy "tbl column starts with span"
.Pq tbl
The first line of a table layout specification
requests a vertical span
.Pq Sq Cm ^ .
Data provided for this cell is ignored, and nothing is printed in the cell.
.It Sy "skipping vertical bar in tbl layout"
.Pq tbl
A table layout specification contains more than two consecutive vertical bars.
A double bar is printed, all additional bars are discarded.
.El
.Ss "Errors related to tables"
.Bl -ohang
.It Sy "non-alphabetic character in tbl options"
.Pq tbl
The table options line contains a character other than a letter,
blank, or comma where the beginning of an option name is expected.
The character is ignored.
.It Sy "skipping unknown tbl option"
.Pq tbl
The table options line contains a string of letters that does not
match any known option name.
The word is ignored.
.It Sy "missing tbl option argument"
.Pq tbl
A table option that requires an argument is not followed by an
opening parenthesis, or the opening parenthesis is immediately
followed by a closing parenthesis.
The option is ignored.
.It Sy "wrong tbl option argument size"
.Pq tbl
A table option argument contains an invalid number of characters.
Both the option and the argument are ignored.
.It Sy "empty tbl layout"
.Pq tbl
A table layout specification is completely empty,
specifying zero lines and zero columns.
As a fallback, a single left-justified column is used.
.It Sy "invalid character in tbl layout"
.Pq tbl
A table layout specification contains a character that can neither
be interpreted as a layout key character nor as a layout modifier,
or a modifier precedes the first key.
The invalid character is discarded.
.It Sy "unmatched parenthesis in tbl layout"
.Pq tbl
A table layout specification contains an opening parenthesis,
but no matching closing parenthesis.
The rest of the input line, starting from the parenthesis, has no effect.
.It Sy "ignoring excessive spacing in tbl layout"
.Pq tbl
A spacing modifier in a table layout is unreasonably large.
The default spacing of 3n is used instead.
.It Sy "tbl without any data cells"
.Pq tbl
A table does not contain any data cells.
It will probably produce no output.
.It Sy "ignoring data in spanned tbl cell"
.Pq tbl
A table cell is marked as a horizontal span
.Pq Sq Cm s
or vertical span
.Pq Sq Cm ^
in the table layout, but it contains data.
The data is ignored.
.It Sy "ignoring extra tbl data cells"
.Pq tbl
A data line contains more cells than the corresponding layout line.
The data in the extra cells is ignored.
.It Sy "data block open at end of tbl"
.Pq tbl
A data block is opened with
.Cm T{ ,
but never closed with a matching
.Cm T} .
The remaining data lines of the table are all put into one cell,
and any remaining cells stay empty.
.El
.Ss "Errors related to roff, mdoc, and man code"
.Bl -ohang
.It Sy "duplicate prologue macro"
.Pq mdoc
One of the prologue macros occurs more than once.
The last instance overrides all previous ones.
.It Sy "skipping late title macro"
.Pq mdoc
The
.Ic \&Dt
macro appears after the first non-prologue macro.
Traditional formatters cannot handle this because
they write the page header before parsing the document body.
Even though this technical restriction does not apply to
.Nm ,
traditional semantics is preserved.
The late macro is discarded including its arguments.
.It Sy "input stack limit exceeded, infinite loop?"
.Pq roff
Explicit recursion limits are implemented for the following features,
in order to prevent infinite loops:
.Bl -dash -compact
.It
expansion of nested escape sequences
including expansion of strings and number registers,
.It
expansion of nested user-defined macros,
.It
and
.Ic \&so
file inclusion.
.El
When a limit is hit, the output is incorrect, typically losing
some content, but the parser can continue.
.It Sy "skipping bad character"
.Pq mdoc , man , roff
The input file contains a byte that is not a printable
.Xr ascii 7
character.
The message mentions the character number.
The offending byte is replaced with a question mark
.Pq Sq \&? .
Consider editing the input file to replace the byte with an ASCII
transliteration of the intended character.
.It Sy "skipping unknown macro"
.Pq mdoc , man , roff
The first identifier on a request or macro line is neither recognized as a
.Xr roff 7
request, nor as a user-defined macro, nor, respectively, as an
.Xr mdoc 7
or
.Xr man 7
macro.
It may be mistyped or unsupported.
The request or macro is discarded including its arguments.
.It Sy "skipping request outside macro"
.Pq roff
A
.Ic shift
or
.Ic return
request occurs outside any macro definition and has no effect.
.It Sy "skipping insecure request"
.Pq roff
An input file attempted to run a shell command
or to read or write an external file.
Such attempts are denied for security reasons.
.It Sy "skipping item outside list"
.Pq mdoc , eqn
An
.Ic \&It
macro occurs outside any
.Ic \&Bl
list, or an
.Xr eqn 7
.Ic above
delimiter occurs outside any pile.
It is discarded including its arguments.
.It Sy "skipping column outside column list"
.Pq mdoc
A
.Ic \&Ta
macro occurs outside any
.Ic \&Bl Fl column
block.
It is discarded including its arguments.
.It Sy "skipping end of block that is not open"
.Pq mdoc , man , eqn , tbl , roff
Various syntax elements can only be used to explicitly close blocks
that have previously been opened.
An
.Xr mdoc 7
block closing macro, a
.Xr man 7
.Ic \&ME , \&RE
or
.Ic \&UE
macro, an
.Xr eqn 7
right delimiter or closing brace, or the end of an equation, table, or
.Xr roff 7
conditional request is encountered but no matching block is open.
The offending request or macro is discarded.
.It Sy "fewer RS blocks open, skipping"
.Pq man
The
.Ic \&RE
macro is invoked with an argument, but less than the specified number of
.Ic \&RS
blocks is open.
The
.Ic \&RE
macro is discarded.
.It Sy "inserting missing end of block"
.Pq mdoc , tbl
Various
.Xr mdoc 7
macros as well as tables require explicit closing by dedicated macros.
A block that doesn't support bad nesting
ends before all of its children are properly closed.
The open child nodes are closed implicitly.
.It Sy "appending missing end of block"
.Pq mdoc , man , eqn , tbl , roff
At the end of the document, an explicit
.Xr mdoc 7
block, a
.Xr man 7
next-line scope or
.Ic \&MT , \&RS
or
.Ic \&UR
block, an equation, table, or
.Xr roff 7
conditional or ignore block is still open.
The open block is closed implicitly.
.It Sy "escaped character not allowed in a name"
.Pq roff
Macro, string and register identifiers consist of printable,
non-whitespace ASCII characters.
Escape sequences and characters and strings expressed in terms of them
cannot form part of a name.
The first argument of an
.Ic \&am ,
.Ic \&as ,
.Ic \&de ,
.Ic \&ds ,
.Ic \&nr ,
or
.Ic \&rr
request, or any argument of an
.Ic \&rm
request, or the name of a request or user defined macro being called,
is terminated by an escape sequence.
In the cases of
.Ic \&as ,
.Ic \&ds ,
and
.Ic \&nr ,
the request has no effect at all.
In the cases of
.Ic \&am ,
.Ic \&de ,
.Ic \&rr ,
and
.Ic \&rm ,
what was parsed up to this point is used as the arguments to the request,
and the rest of the input line is discarded including the escape sequence.
When parsing for a request or a user-defined macro name to be called,
only the escape sequence is discarded.
The characters preceding it are used as the request or macro name,
the characters following it are used as the arguments to the request or macro.
.It Sy "using macro argument outside macro"
.Pq roff
The escape sequence \e$ occurs outside any macro definition
and expands to the empty string.
.It Sy "argument number is not numeric"
.Pq roff
The argument of the escape sequence \e$ is not a digit;
the escape sequence expands to the empty string.
.It Sy "negative argument, using 0"
.Pq roff
A
.Ic \&shift
request has a negative argument
or an argument that is negative due to integer overflow.
Macro argument numbering remains unchanged.
.It Sy "NOT IMPLEMENTED: Bd -file"
.Pq mdoc
For security reasons, the
.Ic \&Bd
macro does not support the
.Fl file
argument.
By requesting the inclusion of a sensitive file, a malicious document
might otherwise trick a privileged user into inadvertently displaying
the file on the screen, revealing the file content to bystanders.
The argument is ignored including the file name following it.
.It Sy "skipping display without arguments"
.Pq mdoc
A
.Ic \&Bd
block macro does not have any arguments.
The block is discarded, and the block content is displayed in
whatever mode was active before the block.
.It Sy "missing list type, using -item"
.Pq mdoc
A
.Ic \&Bl
macro fails to specify the list type.
.It Sy "argument is not numeric, using 1"
.Pq roff
The argument of a
.Ic \&ce
request is not a number.
.It Sy "argument is not a character"
.Pq roff
The first argument of a
.Ic char
request is neither a single ASCII character
nor a single character escape sequence.
The request is ignored including all its arguments.
.It Sy "skipping unusable escape sequence"
.Pq roff
The first argument of an
.Ic mc
request is neither a single ASCII character
nor a single character escape sequence.
All arguments are ignored and printing of a margin character is disabled.
.It Sy "missing manual name, using \(dq\(dq"
.Pq mdoc
The first call to
.Ic \&Nm ,
or any call in the NAME section, lacks the required argument.
.It Sy "uname(3) system call failed, using UNKNOWN"
.Pq mdoc
The
.Ic \&Os
macro is called without arguments, and the
.Xr uname 3
system call failed.
As a workaround,
.Nm
can be compiled with
.Sm off
.Fl D Cm OSNAME=\(dq\e\(dq Ar string Cm \e\(dq\(dq .
.Sm on
.It Sy "unknown standard specifier"
.Pq mdoc
An
.Ic \&St
macro has an unknown argument and is discarded.
.It Sy "skipping request without numeric argument"
.Pq roff , eqn
An
.Ic \&it
request or an
.Xr eqn 7
.Ic \&size
or
.Ic \&gsize
statement has a non-numeric or negative argument or no argument at all.
The invalid request or statement is ignored.
.It Sy "excessive shift"
.Pq roff
The argument of a
.Ic shift
request is larger than the number of arguments of the macro that is
currently being executed.
All macro arguments are deleted and \en(.$ is set to zero.
.It Sy "NOT IMPLEMENTED: .so with absolute path or \(dq..\(dq"
.Pq roff
For security reasons,
.Nm
allows
.Ic \&so
file inclusion requests only with relative paths
and only without ascending to any parent directory.
By requesting the inclusion of a sensitive file, a malicious document
might otherwise trick a privileged user into inadvertently displaying
the file on the screen, revealing the file content to bystanders.
.Nm
only shows the path as it appears behind
.Ic \&so .
.It Sy ".so request failed"
.Pq roff
Servicing a
.Ic \&so
request requires reading an external file, but the file could not be
opened.
.Nm
only shows the path as it appears behind
.Ic \&so .
.It Sy "skipping all arguments"
.Pq mdoc , man , eqn , roff
An
.Xr mdoc 7
.Ic \&Bt ,
.Ic \&Ed ,
.Ic \&Ef ,
.Ic \&Ek ,
.Ic \&El ,
.Ic \&Lp ,
.Ic \&Pp ,
.Ic \&Re ,
.Ic \&Rs ,
or
.Ic \&Ud
macro, an
.Ic \&It
macro in a list that don't support item heads, a
.Xr man 7
.Ic \&LP ,
.Ic \&P ,
or
.Ic \&PP
macro, an
.Xr eqn 7
.Ic \&EQ
or
.Ic \&EN
macro, or a
.Xr roff 7
.Ic \&br ,
.Ic \&fi ,
or
.Ic \&nf
request or
.Sq \&..
block closing request is invoked with at least one argument.
All arguments are ignored.
.It Sy "skipping excess arguments"
.Pq mdoc , man , roff
A macro or request is invoked with too many arguments:
.Bl -dash -offset 2n -width 2n -compact
.It
.Ic \&Fo ,
.Ic \&MT ,
.Ic \&PD ,
.Ic \&RS ,
.Ic \&UR ,
.Ic \&ft ,
or
.Ic \&sp
with more than one argument
.It
.Ic \&An
with another argument after
.Fl split
or
.Fl nosplit
.It
.Ic \&RE
with more than one argument or with a non-integer argument
.It
.Ic \&OP
or a request of the
.Ic \&de
family with more than two arguments
.It
.Ic \&Dt
with more than three arguments
.It
.Ic \&TH
with more than five arguments
.It
.Ic \&Bd ,
.Ic \&Bk ,
or
.Ic \&Bl
with invalid arguments
.El
The excess arguments are ignored.
.El
.Ss "Errors related to escape sequences"
.Bl -ohang
.It Sy "incomplete escape sequence"
.Pq roff
The end of the input line is encountered
while parsing the argument of an escape sequence.
In this case,
.Ic \e*
and
.Ic \en
expand to an empty string,
.Ic \eB
to the digit
.Sq 0 ,
and
.Ic \ew
to the length of the incomplete argument.
All other incomplete escape sequences are ignored.
.It Sy "invalid special character"
.Pq roff
A special character escape sequence is invalid,
for example a Unicode sequence pointing to a surrogate
or beyond the Unicode range, a \e[char...] escape sequence
representing a control character or pointing beyond the
.Vt unsigned char
range, or an invalid variable-length form
of a single-byte character escape sequence, for example writing
.Qq \e[e]
or
.Qq \e[~]
instead of
.Qq \ee
or
.Qq \e~ ,
respectively.
The escape sequence is ignored.
.It Sy "unknown special character"
.Pq roff
The name given in a special character escape sequence is not known to
.Nm .
The escape sequence is ignored.
.It Sy "invalid escape argument delimiter"
.Pq roff
An escape sequence that expects a numerical argument
attempts to employ one of the characters
.Qq " %&()*+-./0123456789:<=>"
as an argument delimiter.
The escape sequence is ignored including the invalid opening delimiter
and the rest of the argument may appear as output text.
While various characters can be used as argument delimiters,
using the apostrophe-quote character
.Pq Sq \(aq
is recommended for readability and robustness.
.El
.Ss Unsupported features
.Bl -ohang
.It Sy "input too large"
.Pq mdoc , man
Currently,
.Nm
cannot handle input files larger than its arbitrary size limit
of 2^31 bytes (2 Gigabytes).
Since useful manuals are always small, this is not a problem in practice.
Parsing is aborted as soon as the condition is detected.
.It Sy "unsupported control character"
.Pq roff
An ASCII control character supported by other
.Xr roff 7
implementations but not by
.Nm
was found in an input file.
It is replaced by a question mark.
.It Sy "unsupported escape sequence"
.Pq roff
An input file contains an escape sequence supported by GNU troff
or Heirloom troff but not by
.Nm ,
and it is likely that this will cause information loss
or considerable misformatting.
.It Sy "unsupported roff request"
.Pq roff
An input file contains a
.Xr roff 7
request supported by GNU troff or Heirloom troff but not by
.Nm ,
and it is likely that this will cause information loss
or considerable misformatting.
.It Sy "eqn delim option in tbl"
.Pq eqn , tbl
The options line of a table defines equation delimiters.
Any equation source code contained in the table will be printed unformatted.
.It Sy "unsupported table layout modifier"
.Pq tbl
A table layout specification contains an
.Sq Cm m
modifier.
The modifier is discarded.
.It Sy "ignoring macro in table"
.Pq tbl , mdoc , man
A table contains an invocation of an
.Xr mdoc 7
or
.Xr man 7
macro or of an undefined macro.
The macro is ignored, and its arguments are handled
as if they were a text line.
.It Sy "skipping tbl in -Tman mode"
.Pq mdoc , tbl
An input file contains the
.Ic \&TS
macro.
This message is only generated in
.Fl T Cm man
output mode, where
.Xr tbl 7
input is not supported.
.It Sy "skipping eqn in -Tman mode"
.Pq mdoc , eqn
An input file contains the
.Ic \&EQ
macro.
This message is only generated in
.Fl T Cm man
output mode, where
.Xr eqn 7
input is not supported.
.El
.Ss Bad command line arguments
.Bl -ohang
.It Sy "bad command line argument"
The argument following one of the
.Fl IKMmOTW
command line options is invalid, or a
.Ar file
given as a command line argument cannot be opened.
.It Sy "duplicate command line argument"
The
.Fl I
command line option was specified twice.
.It Sy "option has a superfluous value"
An argument to the
.Fl O
option has a value but does not accept one.
.It Sy "missing option value"
An argument to the
.Fl O
option has no argument but requires one.
.It Sy "bad option value"
An argument to the
.Fl O
.Cm indent
or
.Cm width
option has an invalid value.
.It Sy "duplicate option value"
The same
.Fl O
option is specified more than once.
.It Sy "no such tag"
The
.Fl O Cm tag
option was specified but the tag was not found in any of the displayed
manual pages.
.It Sy "\-Tmarkdown unsupported for man(7) input"
.Pq man
The
.Fl T Cm markdown
option was specified but an input file uses the
.Xr man 7
language.
No output is produced for that input file.
.El
.Sh SEE ALSO
.Xr apropos 1 ,
.Xr man 1 ,
.Xr eqn 7 ,
.Xr man 7 ,
.Xr mandoc_char 7 ,
.Xr mdoc 7 ,
.Xr roff 7 ,
.Xr tbl 7
.Sh HISTORY
The
.Nm
utility first appeared in
.Ox 4.8 .
The option
.Fl I
appeared in
.Ox 5.2 ,
and
.Fl aCcfhKklMSsw
in
.Ox 5.7 .
.Sh AUTHORS
.An -nosplit
The
.Nm
utility was written by
.An Kristaps Dzonsons Aq Mt kristaps@bsd.lv
and is maintained by
.An Ingo Schwarze Aq Mt schwarze@openbsd.org .