fltk/examples/howto-parse-args.cxx
engelsman 0cbfd64a28 examples/howto-parse-args.cxx: now with added comments and svn:keywords
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@7728 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
2010-10-23 14:10:26 +00:00

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3.3 KiB
C++

//
// "$Id$"
//
// How to parse command line arguments - Duncan Gibson 2010-10-23
// First posted in http://www.fltk.org/newsgroups.php?gfltk.general+v:31449
//
// Shows how to decode additional command line arguments using Fl::args()
// on top of the "standard" options used by the toolkit itself.
//
// Note that this only handles "option separateValue" rather than the
// usual *nix idiom of "option=value", and provides no validation nor
// conversion of the paramter string into ints or floats.
//
// Copyright 1998-2010 by Bill Spitzak and others.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems on the following page:
//
// http://www.fltk.org/str.php
//
#include <stdio.h>
#include <string.h>
#include <FL/Fl.H>
#include <FL/Fl_Box.H>
#include <FL/Fl_Window.H>
int helpFlag = 0;
char *optionString = 0;
/*
* callback function passed to Fl::args() to parse individual argument.
* If there is a match, 'i' must be incremented by 2 or 1 as appropriate.
* If there is no match, Fl::args() will then call Fl::arg() as fallback
* to try to match the "standard" FLTK parameters.
*
* Returns 2 if argv[i] matches with required parameter in argv[i+1],
* returns 1 if argv[i] matches on its own,
* returns 0 if argv[i] does not match.
*/
int arg(int argc, char **argv, int &i)
{
if (strcmp("-h", argv[i]) == 0 || strcmp("--help", argv[i]) == 0) {
helpFlag = 1;
i += 1;
return 1;
}
if (strcmp("-o", argv[i]) == 0 || strcmp("--option", argv[i]) == 0) {
if (i < argc-1 && argv[i+1] != 0) {
optionString = argv[i+1];
i += 2;
return 2;
}
}
return 0;
}
int main(int argc, char** argv)
{
int i = 1;
if (Fl::args(argc, argv, i, arg) < argc)
// note the concatenated strings to give a single format string!
Fl::fatal("error: unknown option: %s\n"
"usage: %s [options]\n"
" -h | --help : print extended help message\n"
" -o | --option # : example option with parameter\n"
" plus standard fltk options\n",
argv[i], argv[0]);
if (helpFlag)
Fl::fatal("usage: %s [options]\n"
" -h | --help : print extended help message\n"
" -o | --option # : example option with parameter\n"
" plus standard fltk options:\n"
"%s\n",
argv[0], Fl::help);
Fl_Window* mainWin = new Fl_Window(300, 200);
Fl_Box* textBox = new Fl_Box(0, 0, 300, 200);
if (optionString != 0)
textBox->label(optionString);
else
textBox->label("re-run with [-o|--option] text");
mainWin->show(argc, argv);
return Fl::run();
}
//
// End of "$Id$".
//