| tronayne |
02-21-2008 08:56 AM |
The standard changed (I think) -- you can't define a void main() in C++ but you can (or could, I'm not completely clear on this) in C; there's a lot of discussion about this all over the place. You can tell GCC to shut up about it, and you can define your main as void and it'll work just fine (Sun C, for example, doesn't give a hoot if you define main as void). One of the things you should do in any event is exit (status), rather than letting the program fall off the end; here's the template I use to begin C programs with in Linux or Solaris that demonstrates this:
Code:
#ident "$Id$"
/*
* Copyright (C) 2008 Your Name or Organization Goes Here
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General
* Public License as published by the Free Software Foundation.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*
* Name: $Source$
* Purpose: brief description goes here
* Version: $Revision$
* Modified: $Date$
* Author: Your Name Goes Here
* Date: Today's Date
* $Log$
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#ifndef TRUE
# define TRUE 1
#endif
#ifndef FALSE
# define FALSE 0
#endif
void main (int argc, char *argv [])
{
int c; /* general-purpose */
int error = FALSE; /* error flag */
int vopt = FALSE; /* verbose option */
time_t t0 = (time_t) 0; /* start time */
time_t t1 = (time_t) 0; /* finish time */
FILE *in;
/* process the command line arguments */
while ((c = getopt (argc, argv, "?v")) != EOF) {
switch (c) {
case '?':
error = TRUE;
break;
case 'v':
vopt = TRUE;
break;
default:
(void) fprintf (stderr, "getopt() bug\n");
exit (EXIT_FAILURE);
}
}
/* any errors in the arguments, or a '?' entered...*/
if (error) {
(void) fprintf (stderr, "usage: %s [-v] argument...\n",
argv [0]);
exit (EXIT_FAILURE);
}
/* get a start time */
if (time (&t0) < (time_t) 0)
(void) fprintf (stderr,
"%s:\tcan't read system clock\n", argv [0]);
/* now process any arguments supplied... */
while (optind != argc) {
(void) fprintf (stderr, "Processing %s...\n", argv [optind]);
/* open the input file */
if ((in = fopen (argv [optind], "r")) == (FILE *) NULL) {
(void) fprintf (stderr,
"%s:\tcan't open %s\n",
argv [0], argv [optind]);
exit (EXIT_FAILURE);
}
/* your program code goes here */
/* close the input file */
if (fclose (in))
(void) fprintf (stderr,
"%s:\tcan't close %s\n",
argv [0], argv [optind]);
optind++;
}
/* get a finish time */
if (time (&t1) < (time_t) 0)
(void) fprintf (stderr,
"%s:\tcan't read system clock\n", argv [0]);
if (vopt)
(void) fprintf (stderr,
"%s duration %g seconds\n",
argv [0], difftime (t1, t0));
exit (EXIT_SUCCESS);
}
And, yes, I define them as void until I get sick of GCC yammering at me about it.
Hope this helps some. |
