| <html lang="en"> |
| <head> |
| <title>Suboptions Example - The GNU C Library</title> |
| <meta http-equiv="Content-Type" content="text/html"> |
| <meta name="description" content="The GNU C Library"> |
| <meta name="generator" content="makeinfo 4.13"> |
| <link title="Top" rel="start" href="index.html#Top"> |
| <link rel="up" href="Parsing-Program-Arguments.html#Parsing-Program-Arguments" title="Parsing Program Arguments"> |
| <link rel="prev" href="Suboptions.html#Suboptions" title="Suboptions"> |
| <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> |
| <!-- |
| This file documents the GNU C library. |
| |
| This is Edition 0.12, last updated 2007-10-27, |
| of `The GNU C Library Reference Manual', for version |
| 2.8 (Sourcery G++ Lite 2011.03-41). |
| |
| Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002, |
| 2003, 2007, 2008, 2010 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being ``Free Software Needs Free Documentation'' |
| and ``GNU Lesser General Public License'', the Front-Cover texts being |
| ``A GNU Manual'', and with the Back-Cover Texts as in (a) below. A |
| copy of the license is included in the section entitled "GNU Free |
| Documentation License". |
| |
| (a) The FSF's Back-Cover Text is: ``You have the freedom to |
| copy and modify this GNU manual. Buying copies from the FSF |
| supports it in developing GNU and promoting software freedom.''--> |
| <meta http-equiv="Content-Style-Type" content="text/css"> |
| <style type="text/css"><!-- |
| pre.display { font-family:inherit } |
| pre.format { font-family:inherit } |
| pre.smalldisplay { font-family:inherit; font-size:smaller } |
| pre.smallformat { font-family:inherit; font-size:smaller } |
| pre.smallexample { font-size:smaller } |
| pre.smalllisp { font-size:smaller } |
| span.sc { font-variant:small-caps } |
| span.roman { font-family:serif; font-weight:normal; } |
| span.sansserif { font-family:sans-serif; font-weight:normal; } |
| --></style> |
| <link rel="stylesheet" type="text/css" href="../cs.css"> |
| </head> |
| <body> |
| <div class="node"> |
| <a name="Suboptions-Example"></a> |
| <p> |
| Previous: <a rel="previous" accesskey="p" href="Suboptions.html#Suboptions">Suboptions</a>, |
| Up: <a rel="up" accesskey="u" href="Parsing-Program-Arguments.html#Parsing-Program-Arguments">Parsing Program Arguments</a> |
| <hr> |
| </div> |
| |
| <h4 class="subsection">25.3.13 Parsing of Suboptions Example</h4> |
| |
| <p>The code which might appear in the <code>mount</code>(8) program is a perfect |
| example of the use of <code>getsubopt</code>: |
| |
| <pre class="smallexample"> #include <stdio.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| |
| int do_all; |
| const char *type; |
| int read_size; |
| int write_size; |
| int read_only; |
| |
| enum |
| { |
| RO_OPTION = 0, |
| RW_OPTION, |
| READ_SIZE_OPTION, |
| WRITE_SIZE_OPTION, |
| THE_END |
| }; |
| |
| const char *mount_opts[] = |
| { |
| [RO_OPTION] = "ro", |
| [RW_OPTION] = "rw", |
| [READ_SIZE_OPTION] = "rsize", |
| [WRITE_SIZE_OPTION] = "wsize", |
| [THE_END] = NULL |
| }; |
| |
| int |
| main (int argc, char *argv[]) |
| { |
| char *subopts, *value; |
| int opt; |
| |
| while ((opt = getopt (argc, argv, "at:o:")) != -1) |
| switch (opt) |
| { |
| case 'a': |
| do_all = 1; |
| break; |
| case 't': |
| type = optarg; |
| break; |
| case 'o': |
| subopts = optarg; |
| while (*subopts != '\0') |
| switch (getsubopt (&subopts, mount_opts, &value)) |
| { |
| case RO_OPTION: |
| read_only = 1; |
| break; |
| case RW_OPTION: |
| read_only = 0; |
| break; |
| case READ_SIZE_OPTION: |
| if (value == NULL) |
| abort (); |
| read_size = atoi (value); |
| break; |
| case WRITE_SIZE_OPTION: |
| if (value == NULL) |
| abort (); |
| write_size = atoi (value); |
| break; |
| default: |
| /* <span class="roman">Unknown suboption.</span> */ |
| printf ("Unknown suboption `%s'\n", value); |
| break; |
| } |
| break; |
| default: |
| abort (); |
| } |
| |
| /* <span class="roman">Do the real work.</span> */ |
| |
| return 0; |
| } |
| </pre> |
| </body></html> |
| |
