table of contents
other versions
- wheezy 3.44-1
- jessie 3.74-1
- jessie-backports 4.10-2~bpo8+1
- testing 4.10-2
- unstable 4.10-2
GETSUBOPT(3) | Linux Programmer's Manual | GETSUBOPT(3) |
NAME¶
getsubopt - parse suboption arguments from a stringSYNOPSIS¶
#include <stdlib.h>Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
|| /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
DESCRIPTION¶
getsubopt() parses the list of comma-separated suboptions provided in optionp. (Such a suboption list is typically produced when getopt(3) is used to parse a command line; see for example the -o option of mount(8).) Each suboption may include an associated value, which is separated from the suboption name by an equal sign. The following is an example of the kind of string that might be passed in optionp:ro,name=xyz
RETURN VALUE¶
If the first suboption in optionp is recognized, getsubopt() returns the index of the matching suboption element in tokens. Otherwise, -1 is returned and *valuep is the entire name[=value] string.CONFORMING TO¶
POSIX.1-2001.NOTES¶
Since getsubopt() overwrites any commas it finds in the string *optionp, that string must be writable; it cannot be a string constant.EXAMPLE¶
The following program expects suboptions following a "-o" option.#define _XOPEN_SOURCE 500 #include <stdlib.h> #include <assert.h> #include <stdio.h> int main(int argc, char **argv) { enum { RO_OPT = 0, RW_OPT, NAME_OPT }; char *const token[] = { [RO_OPT] = "ro", [RW_OPT] = "rw", [NAME_OPT] = "name", NULL }; char *subopts; char *value; int opt; int readonly = 0; int readwrite = 0; char *name = NULL; int errfnd = 0; while ((opt = getopt(argc, argv, "o:")) != -1) { switch (opt) { case 'o': subopts = optarg; while (*subopts != '\0' && !errfnd) { switch (getsubopt(&subopts, token, &value)) { case RO_OPT: readonly = 1; break; case RW_OPT: readwrite = 1; break; case NAME_OPT: if (value == NULL) { fprintf(stderr, "Missing value for " "suboption '%s'\n", token[NAME_OPT]); errfnd = 1; continue; } name = value; break; default: fprintf(stderr, "No match found " "for token: /%s/\n", value); errfnd = 1; break; } } if (readwrite && readonly) { fprintf(stderr, "Only one of '%s' and '%s' can be " "specified\n", token[RO_OPT], token[RW_OPT]); errfnd = 1; } break; default: errfnd = 1; } } if (errfnd || argc == 1) { fprintf(stderr, "\nUsage: %s -o <suboptstring>\n", argv[0]); fprintf(stderr, "suboptions are 'ro', 'rw', " "and 'name=<value>'\n"); exit(EXIT_FAILURE); } /* Remainder of program... */ exit(EXIT_SUCCESS); }
SEE ALSO¶
getopt(3)COLOPHON¶
This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.2010-09-26 | GNU |