Manual Pages for UNIX Operating System command usage for man getsubopt
Standard C Library Functions getsubopt(3C)
NAME
getsubopt - parse suboption arguments from a string
SYNOPSIS
#include
int getsubopt(char **optionp, char * const *keylistp, char **valuep);
DESCRIPTION
The getsubopt() function parses suboption arguments in a
flag argument. Such options often result from the use of
getopt(3C).
The getsubopt() argument optionp is a pointer to a pointer
to the option argument string. The suboption arguments are
separated by commas and each can consist of either a single
token or a token-value pair separated by an equal sign.
The keylistp argument is a pointer to a vector of strings.
The end of the vector is identified by a null pointer. Each
entry in the vector is one of the possible tokens that might
be found in *optionp. Since commas delimit suboption argu-
ments in optionp, they should not appear in any of the
strings pointed to by keylistp. Similarly, because an equal
sign separates a token from its value, the application
should not include an equal sign in any of the strings
pointed to by keylistp.
The valuep argument is the address of a value string
pointer.
If a comma appears in optionp, it is interpreted as a subop-
tion separator. After commas have been processed, if there
are one or more equal signs in a suboption string, the first
equal sign in any suboption string is interpreted as a
separator between a token and a value. Subsequent equal
signs in a suboption string are interpreted as part of the
value.
If the string at *optionp contains only one suboption argu-
ment (equivalently, no commas), getsubopt() updates *optionp
to point to the null character at the end of the string.
Otherwise, it isolates the suboption argument by replacing
the comma separator with a null character and updates
*optionp to point to the start of the next suboption argu-
ment. If the suboption argument has an associated value
SunOS 5.11 Last change: 29 Sep 2005 1
Standard C Library Functions getsubopt(3C)
(equivalently, contains an equal sign), getsubopt() updates
*valuep to point to the value's first character. Otherwise,
it sets *valuep to a null pointer. The calling application
can use this information to determine whether the presence
or absence of a value for the suboption is an error.
Additionally, when getsubopt() fails to match the suboption
with a token in the keylistp array, the calling application
should decide if this is an error or if the unrecognized
option should be processed in another way.
RETURN VALUES
The getsubopt() function returns the index of the matched
token string or -1 if no token strings were matched.
ERRORS
No errors are defined.
EXAMPLES
Example 1 Use getsubopt() to process options.
The following example demonstrates the processing of options
to the mount(1M) utility using getsubopt().
#include
char *myopts[] = {
#define READONLY 0
"ro",
#define READWRITE 1
"rw",
#define WRITESIZE 2
"wsize",
#define READSIZE 3
"rsize",
NULL};
main(argc, argv)
int argc;
char **argv;
{
int sc, c, errflag;
char *options, *value;
extern char *optarg;
extern int optind;
.
.
.
while((c = getopt(argc, argv, "abf:o:")) != -1) {
SunOS 5.11 Last change: 29 Sep 2005 2
Standard C Library Functions getsubopt(3C)
switch (c) {
case 'a': /* process a option */
break;
case 'b': /* process b option */
break;
case 'f':
ofile = optarg;
break;
case '?':
errflag++;
break;
case 'o':
options = optarg;
while (*options != '\0') {
switch(getsubopt(&options,myopts,&value)){
case READONLY : /* process ro option */
break;
case READWRITE : /* process rw option */
break;
case WRITESIZE : /* process wsize option */
if (value == NULL) {
error_no_arg();
errflag++;
} else
write_size = atoi(value);
break;
case READSIZE : /* process rsize option */
if (value == NULL) {
error_no_arg();
errflag++;
} else
read_size = atoi(value);
break;
default :
/* process unknown token */
error_bad_token(value);
errflag++;
break;
}
}
break;
}
}
if (errflag) {
/* print usage instructions etc. */
}
for (; optindSunOS 5.11 Last change: 29 Sep 2005 3
Standard C Library Functions getsubopt(3C)
}
Example 2 Parse suboptions.
The following example uses the getsubopt() function to parse
a value argument in the optarg external variable returned by
a call to getopt(3C).
#include
...
char *tokens[] = {"HOME", "PATH", "LOGNAME", (char *) NULL };
char *value;
int opt, index;
while ((opt = getopt(argc, argv, "e:")) != -1) {
switch(opt) {
case 'e' :
while ((index = getsubopt(&optarg, tokens, &value)) != -1) {
switch(index) {
...
}
break;
...
}
}
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Interface Stability | Committed |
|_____________________________|_____________________________|
| MT-Level | MT-Safe |
|_____________________________|_____________________________|
| Standard | See standards(5). |
|_____________________________|_____________________________|
SEE ALSO
mount(1M), getopt(3C), attributes(5), standards(5)
SunOS 5.11 Last change: 29 Sep 2005 4