source: buchla-68k/orig/DOC/GETOPT.TXT@ 7bf3856

Last change on this file since 7bf3856 was 3ae31e9, checked in by Thomas Lopatic <thomas@…>, 7 years ago

Imported original source code.
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4 GETOPT(3) UNIX 5.0 (21 January 1986) GETOPT(3)
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7 NAME
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9 getopt, optarg, optind - get option letter from argv
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11 SYNOPSIS
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13 int getopt(argc, argv, opts)
14 int argc;
15 char **argv;
16 char *opts;
17
18 int
19 getarg(nargc, nargv)
20 int nargc;
21 char *nargv[];
22
23 extern int optind;
24 extern int opterr;
25 extern int optopt;
26 extern char *optarg;
27
28 DESCRIPTION
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30 This is the public domain getopt from AT&T with enhancements.
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32 Getopt returns the next option letter in argv that matches a
33 letter in opts. Opts is a string of recognized option
34 letters; if a letter is followed by a colon, the option is
35 expected to have an argument that may or may not be
36 separated from it by white space. Optarg is set to point to
37 the start of the option argument on return from getopt.
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39 Getopt places in optind the argv index of the next argument
40 to be processed. Optind is external and it is normally
41 initialized to one automatically before the first call to
42 getopt. This is so that the program name will not be processed
43 as an argument if getopt is used to process the command line
44 passed to the main function of a program.
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46 When all options have been processed (i.e., up to the first
47 non-option argument), getopt returns EOF. The special option
48 -- may be used to delimit the end of the options; EOF will
49 be returned, and -- will be skipped.
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51
52 Getarg returns the index of the next argument, or EOF if the
53 argument string is exhausted. Getarg is used to get the file
54 arguments after getopt() is finished. Getarg updates optarg
55 to point at the argument, and increments optind to point
56 at the next argument.
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61 GETOPT(3) UNIX 5.0 (21 January 1986) GETOPT(3)
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63
64 DIAGNOSTICS
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66 Getopt prints an error message on stderr (if opterr is non-
67 zero) and returns a question mark (?) when it encounters an
68 option letter not included in opts. The error message uses
69 argv[0] as the program name. If this is not desireable, set
70 opterr = 0 and issue your own error message when getopt
71 returns '?'.
72
73 EXAMPLE
74
75 The following code fragment shows how one might process the
76 arguments for a command that can take the mutually exclusive
77 options a and b, and the options f and o, both of which
78 require arguments:
79
80 main(argc, argv)
81 int argc;
82 char **argv;
83 {
84 int c;
85 extern int optind;
86 extern char *optarg;
87
88 ...
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93 GETOPT(3) UNIX 5.0 (21 January 1986) GETOPT(3)
94
95
96 while ((c = getopt(argc, argv, "abf:o:")) != EOF)
97 switch (c) {
98
99 case 'a':
100 if (bflg)
101 errflg++;
102 else
103 aflg++;
104 break;
105
106 case 'b':
107 if (aflg)
108 errflg++;
109 else
110 bproc();
111 break;
112
113 case 'f':
114 infile = optarg;
115 break;
116
117 case 'o':
118 ofile = optarg;
119 bufsiza = 512;
120 break;
121
122 case '?':
123 errflg++;
124 }
125
126 if (errflg) {
127 fprintf(stderr, "usage: . . . ");
128 exit(2);
129 }
130
131 for (; optind < argc; optind++) {
132
133 if (access(argv[optind], 4)) {
134
135 ...
136 }
137 }
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