Autzoo.1269 net.sources utcsrgv!utzoo!henry Mon Jan 11 15:42:39 1982 getopt(3) The following is the source and manual page for a getopt() routine written locally to match the description in a copy of the Unix 3.0 manual that I got to see once. Behavior is believed identical to the Bell one, but this is NOT Bell code and carries no nondisclosure restrictions. Use it on any system you wish. ------------ /* * getopt - get option letter from argv */ #include char *optarg; /* Global argument pointer. */ int optind = 0; /* Global argv index. */ static char *scan = NULL; /* Private scan pointer. */ extern char *index(); int getopt(argc, argv, optstring) int argc; char *argv[]; char *optstring; { register char c; register char *place; optarg = NULL; if (scan == NULL || *scan == '\0') { if (optind == 0) optind++; if (optind >= argc || argv[optind][0] != '-' || argv[optind][1] == '\0') return(EOF); if (strcmp(argv[optind], "--")==0) { optind++; return(EOF); } scan = argv[optind]+1; optind++; } c = *scan++; place = index(optstring, c); if (place == NULL || c == ':') { fprintf(stderr, "%s: unknown option -%c\n", argv[0], c); return('?'); } place++; if (*place == ':') { if (*scan != '\0') { optarg = scan; scan = NULL; } else { optarg = argv[optind]; optind++; } } return(c); } ------------ .TH GETOPT 3 local .DA 28 Oct 1981 .SH NAME getopt \- get option letter from argv .SH SYNOPSIS .ft B int getopt(argc, argv, optstring) .br int argc; .br char **argv; .br char *optstring; .sp extern char *optarg; .br extern int optind; .ft .SH DESCRIPTION .I Getopt returns the next option letter in .I argv that matches a letter in .IR optstring . .I Optstring is a string of recognized option letters; if a letter is followed by a colon, the option is expected to have an argument that may or may not be separated from it by white space. .I Optarg is set to point to the start of the option argument on return from .IR getopt . .PP .I Getopt places in .I optind the .I argv index of the next argument to be processed. Because .I optind is external, it is normally initialized to zero automatically before the first call to .IR getopt . .PP When all options have been processed (i.e., up to the first non-option argument), .I getopt returns .BR EOF . The special option .B \-\- may be used to delimit the end of the options; .B EOF will be returned, and .B \-\- will be skipped. .SH SEE ALSO getopt(1) .SH DIAGNOSTICS .I Getopt prints an error message on .I stderr and returns a question mark .RB ( ? ) when it encounters an option letter not included in .IR optstring . .SH EXAMPLE The following code fragment shows how one might process the arguments for a command that can take the mutually exclusive options .B a and .BR b , and the options .B f and .BR o , both of which require arguments: .PP .RS .nf main(argc, argv) int argc; char **argv; { int c; extern int optind; extern char *optarg; \&. \&. \&. while ((c = getopt(argc, argv, "abf:o:")) != EOF) switch (c) { case 'a': if (bflg) errflg++; else aflg++; break; case 'b': if (aflg) errflg++; else bproc(); break; case 'f': ifile = optarg; break; case 'o': ofile = optarg; break; case '?': errflg++; } if (errflg) { fprintf(stderr, "Usage: ..."); exit(2); } for (; optind
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Return to the Usenet Oldnews Archive index ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.