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.\" @(#)getsubopt.3 8.1 (Berkeley) 6/9/93
.Nd get sub options from an argument
.Vt extern char *suboptarg
.Fn getsubopt "char **optionp" "char * const *tokens" "char **valuep"
parses a string containing tokens delimited by one or more tab, space or
It is intended for use in parsing groups of option arguments provided
as part of a utility command line.
is a pointer to a pointer to the string.
array of pointers to strings.
returns the zero-based offset of the pointer in the
array referencing a string which matches the first token
in the string, or, \-1 if the string contains no tokens or
does not contain a matching string.
If the token is of the form ``name=value'', the location referenced by
will be set to point to the start of the ``value'' portion of the token.
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.
will be set to point to the start of the current token, or
will be set to point to the ``value'' portion of the token, or
if no ``value'' portion was present.
extern char *optarg, *suboptarg;
while ((ch = getopt(argc, argv, "ab:")) != \-1) {
/* process ``a'' option */
switch(getsubopt(&options, tokens, &value)) {
/* process ``one'' sub option */
/* process ``two'' sub option */
error("no value for two");
error("illegal sub option %s",
error("missing sub option");
function first appeared in 4.4BSD.