doc/getopt/README - master - githubmirror/libsmbios

doc/getopt/README
118 строк4 KB
Ivan Sharavuev
Fix misspelling in doc/getopt/README
31 окт 2018, 17:42
31 окт 2018, 17:4226e7363
getopts v0.3.0 {http://www.dragon-ware.com/~steve/projects/getopts}
Written by: Steve Mertz <steve@dragon-ware.com>
License: BSD Style
Development Environment: Slackware 7.1, gcc 2.95.2
Development Environment: Slackware 8.1, gcc 2.95.3
Development Environment: FreeBSD 5.0-CURRENT (20020210)
Known to work on: OpenBSD, Windows, FreeBSD, Linux
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

GetOpts is a command line parser.  It was built because the author couldn't
find a command line parser that he liked.

Easy to use.  

In the file that contains your main()...

/* See included main.c */

#include <stdlib.h>
#include <stdio.h>
#include "getopts.h"

int main(int argc, char **argv)
{
  char *args;
  int c;

  struct options opts[] = 
  {
    { 1, "debug",   "Set the debugging level", "d", 1 },
    { 2, "version", "Display the version info", "V", 0 },
    { 3, NULL,      "Set the config file",      "f", 1 },
    { 4, "test",    "Test getopts_usage",       "t", 0 },
    { 0, NULL,      NULL,                      NULL, 0 }
  };

  while ((c = getopts(argc, argv, opts, args)) != 0)
    {
      switch(c)
        {
          case 1:
            printf("Setting debug level to: %s\n", args);
/*            setDebugLevel(args); */
            break;
          case 2:
            printf("ProgName 0.1.1\n");
            printf("Written by: Steve Mertz\n");
            exit(0);
            break;
          case 3:
            printf("Setting config file to: %s\n", args);
/*            readConfig(args); */
            break;
          case 4:
            /* This is just to test.  "argv[0]" is the program name */
            getopts_usage(argv[0], opts);
            break;
          default:
            break;
        }
/* This free() is required since getopts() automagically allocates space
   for "args" everytime it's called. */
      free(args);
    }
  return 0;
} 


This example program.  Please note there is no -h or --help, as these are
built in to the getopts() function, which is why in the array that is declared,
you enter a description.  It should format everything correctly in the help if
things aren't too long.

Looking at the options struct.  

{ 1, "debug",   "Set the debugging level", "d", 1 },

This first entry here is '1', this is the number that getopts() will return
if it matches any of the command line arguments.  The next entry "debug" is
the long name of the command line argument.  It will be used like "--debug".
The third entry is the description.  This is what will be shown in the event
of using "-h" or "--help".  Or should the arguments not be there and it 
decides to dump out the usage. The fourth entry is the short name or "-d" as
it would be seen on the command line.  The last (fifth) entry '1' is going to
be either a one or a zero.  And it tells if there are any arguments for this 
option.  like "--debug 3" could be used here for setting debug level to '3'.

Either the fullname (entry 2) or the short name (entry 4) can have NULL for
its entry, signifying it should only use one or the other.  But you need 
at least 1 of them.  

-- IGNORE THIS PARAGRAPH --  This is only here for Historical references.
At this current time, you can only have 1 argument for an option (space
delimited). In the next release I may change this so that you can have either
multiple arguments or have quoted arguments.
-------------------------------------------------------------------------------

NEW:
~~~~
20020822 -- Added a new function: getopts_usage()  This is so you can call 
            getopts_usage() from within your own program to get the usage
            should you want to.  Thanks to Tim Tassonis for this idea.

TODO:
~~~~~
o Use proper formatting techniques rather than just tab spacing.
o Write better documentation.
o Have multiple arguments for options.


BUGS (fixed):
~~~~~~~~~~~~~
20020822 -- A seg fault would occur if you didn't use arguments for the options. -- Tim Tassonis
20020719 -- Static buffers for option arguments  -- Tim Tassonis
         -- Memory Leaks (found thanks to Tim!)
         -- Wasted Cycles (took out code that didn't actually do anything.)
20011218 -- Could not use '-' in arguments for options. -- Dirk Eddelbuettel
20010113 -- None as of today that I know of.  -- Steve Mertz