GETSUBOPT(3) Library Functions Manual GETSUBOPT(3)

getsubopt — get sub options from an argument

Standard C Library (libc, -lc)

#include <stdlib.h>

extern char *suboptarg;

int
getsubopt(char **optionp, char *const *keylistp, char **valuep);

The () function parses a string containing tokens that are delimited by one or more tab, space, or comma (‘,’) characters. It is intended for use in parsing groups of option arguments that are provided as part of a utility command line.

The argument optionp is a pointer to a pointer to the string. The argument keylistp is a pointer to a NULL-terminated array of pointers to strings.

The () function returns the zero-based offset of the pointer in the keylistp array, referencing a string which matches the first token in the string
or -1 if the string contains no tokens or keylistp does not contain a matching string.

If the token is of the form ``name=value'', the location referenced by valuep will be set to point to the start of the ``value'' portion of the token.

On return from (), optionp will be set to point to the start of the next token in the string, or the null at the end of the string if no more tokens are present. The external variable suboptarg will be set to point to the start of the current token, or NULL if no tokens were present. The argument valuep will be set to point to the ``value'' portion of the token, or NULL if no ``value'' portion was present.

char *keylistp[] = {
	#define	ONE	0
		"one",
	#define	TWO	1
		"two",
	NULL
};

...

extern char *optarg, *suboptarg;
char *options, *value;

while ((ch = getopt(argc, argv, "ab:")) != -1) {
	switch(ch) {
	case 'a':
		/* process ``a'' option */
		break;
	case 'b':
		options = optarg;
		while (*options) {
			switch(getsubopt(&options, keylistp, &value)) {
			case ONE:
				/* process ``one'' sub option */
				break;
			case TWO:
				/* process ``two'' sub option */
				if (!value)
					error("no value for two");
				i = atoi(value);
				break;
			case -1:
				if (suboptarg)
					error("illegal sub option %s",
					  suboptarg);
				else
					error("missing sub option");
				break;
		}
		break;
	}

getopt(3), strsep(3)

The getsubopt() function first appeared in 4.4BSD.

June 9, 1993 macOS 15.2