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getopt.c
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C/C++ Source or Header
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2001-12-12
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2KB
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61 lines
/*
* getopt.c -- get command-line options.
*/
#include "../h/gsupport.h"
#ifndef SysOpt
extern char* progname;
/*
* Based on a public domain implementation of System V
* getopt(3) by Keith Bostic (keith@seismo), Aug 24, 1984.
*/
#define BadCh (int)'?'
#define EMSG ""
#define tell(m) fprintf(stderr,"%s: %s -- %c\n",progname,m,optopt);return BadCh;
int optind = 1; /* index into parent argv vector */
int optopt; /* character checked for validity */
char *optarg; /* argument associated with option */
int getopt(int nargc, char *const nargv[], const char *ostr)
{
static char *place = EMSG; /* option letter processing */
register char *oli; /* option letter list index */
if(!*place) { /* update scanning pointer */
if(optind >= nargc || *(place = nargv[optind]) != '-' || !*++place)
return EOF;
if (*place == '-') { /* found "--" */
++optind;
return EOF;
}
} /* option letter okay? */
if (((optopt=(int)*place++) == (int)':') || (oli=strchr(ostr,optopt)) == 0) {
if(!*place) ++optind;
tell("illegal option");
}
if (*++oli != ':') { /* don't need argument */
optarg = NULL;
if (!*place) ++optind;
}
else { /* need an argument */
if (*place) optarg = place; /* no white space */
else if (nargc <= ++optind) { /* no arg */
place = EMSG;
tell("option requires an argument");
}
else optarg = nargv[optind]; /* white space */
place = EMSG;
++optind;
}
return optopt; /* dump back option letter */
}
#else /* SysOpt */
static char junk; /* prevent empty file */
#endif /* SysOpt */