Gobligine/etlib/getopt.c
2002-05-14 17:17:12 +00:00

100 lines
1.8 KiB
C

/*
* Standard implementation of getopt(3).
*
* One extension: If the first character of the optionsstring is a ':'
* the error return for 'argument required' is a ':' not a '?'.
* This makes it easier to differentiate between an 'illegal option' and
* an 'argument required' error.
*
* Another extension: the external variable prgname is set from argv[0].
*/
#include "prgname.h"
#define NULL 0
#define EOF (-1)
extern int write();
extern int strlen();
extern int strcmp();
extern char *strchr();
int opterr = 1;
int optind = 1;
int optopt;
char *optarg;
static void
getopt_err(char *argv0, char *str, char opt)
{
if (opterr)
{
char errbuf[2];
char *x;
errbuf[0] = opt;
errbuf[1] = '\n';
while ((x = strchr(argv0, '/')))
argv0 = x + 1;
write(2, argv0, strlen(argv0));
write(2, str, strlen(str));
write(2, errbuf, 2);
}
}
int
getopt(argc, argv, opts)
int argc;
char **argv, *opts;
{
static int sp = 1;
register int c;
register char *cp;
setprgname(argv[0]);
optarg = NULL;
if (sp == 1)
{
if (optind >= argc || argv[optind][0] != '-' || argv[optind][1] == '\0')
return EOF;
else if (strcmp(argv[optind], "--") == NULL)
{
optind++;
return EOF;
}
}
optopt = c = argv[optind][sp];
if (c == ':' || (cp = strchr(opts, c)) == NULL)
{
getopt_err(argv[0], ": illegal option -", (char)c);
cp = "xx"; /* make the next if false */
c = '?';
}
if (*++cp == ':')
{
if (argv[optind][++sp] != '\0')
optarg = &argv[optind++][sp];
else if (++optind < argc)
optarg = argv[optind++];
else
{
getopt_err(argv[0], ": option requires an argument -", (char)c);
c = (*opts == ':') ? ':' : '?';
}
sp = 1;
}
else if (argv[optind][++sp] == '\0')
{
optind++;
sp = 1;
}
return c;
}