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GETOPT.C
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C/C++ Source or Header
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1993-07-02
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2KB
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74 lines
/* optarg - parse command-line arguments */
/* Author: AT&T */
#include <stdio.h>
#define ERR(s, c) if(opterr){\
char errbuf[2];\
errbuf[0] = c; errbuf[1] = '\n';\
fwrite(argv[0], 1, (unsigned)strlen(argv[0]),stderr);\
fwrite(s, 1, (unsigned)strlen(s),stderr);\
fwrite(errbuf, 1, 2, stderr);}
extern int strcmp();
extern char *strchr();
extern int strlen();
int opterr = 1; /* getopt prints errors if this is on */
int optind = 1; /* token pointer */
int optopt; /* option character passed back to user */
char *optarg; /* flag argument (or value) */
int /* return option character, EOF if no more or ? if problem */
getopt(argc, argv, opts)
int argc;
char **argv;
char *opts; /* option string */
{
static int sp = 1; /* character index in current token */
register char *cp; /* pointer into current token */
if(sp == 1)
/* check for more flag-like tokens */
if(optind >= argc ||
argv[optind][0] != '-' || argv[optind][1] == '\0')
return(EOF);
else if(strcmp(argv[optind], "--") == 0) {
optind++;
return(EOF);
}
optopt = argv[optind][sp];
if(optopt == ':' || (cp=strchr(opts, optopt)) == 0) {
ERR(": illegal option -- ", optopt);
/* if no chars left in this token, move to next token */
if(argv[optind][++sp] == '\0') {
optind++;
sp = 1;
}
return('?');
}
if(*++cp == ':') { /* if a value is expected, get it */
if(argv[optind][sp+1] != '\0')
/* flag value is rest of current token */
optarg = &argv[optind++][sp+1];
else if(++optind >= argc) {
ERR(": option requires an argument -- ", optopt);
sp = 1;
return('?');
} else
/* flag value is next token */
optarg = argv[optind++];
sp = 1;
} else {
/* set up to look at next char in token, next time */
if(argv[optind][++sp] == '\0') {
/* no more in current token, so setup next token */
sp = 1;
optind++;
}
optarg = 0;
}
return(optopt);/* return the current flag character found */
}