From: "Robert B. Clark" <rclark AT iquest DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: My program's a machine killer!
Organization: ClarkWehyr Enterprises
Message-ID: <0paj9sgcf064paiv56h1tb5aei3r0bncpk@4ax.com>
References: <2d1m4.294$oU2 DOT 94919 AT tw12 DOT nn DOT bcandid DOT com>
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Date: Thu, 03 Feb 2000 11:30:06 -0500
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

"Brian" <none AT noemail DOT com> wrote:

>When I run the short little program below, my PC reboots. I don't have VESA
>so I set my graphics mode to VGA 320x200. I don't know if this is a problem.

I must preface this with the assertion that I am not familiar with
Allegro.  That being said, I do have a few comments on your code.

>char *listbox_getter(int index, int *list_size)
>{
>    static char *strings[] =
>    {
>        "Entry 1", "Entry 2", "Entry 3"
>    };
>
>    if (index < 0)
>    {
>        *list_size = 3;
>        return NULL;
>    }

You might want to also check for index > 2 here.  Try this alternative:

	#define NUM_ENTRIES		3

	char *listbox_getter(int index, int *list_size)
	{
		static char *strings[NUM_ENTRIES] = 
		{
			"Entry1", "Entry2", "Entry3"
		};

		if (index < 0 || index >= NUM_ENTRIES)
		{
			*list_size = NUM_ENTRIES;
			return NULL;
		}
		else
			return strings[index];
	}

As a matter of fact (if it makes sense to the rest of your code), you
might want to consider making index and list_size unsigned ints or
size_t values, just to avoid having to check for the negative condition.

>#define LISTBOX_OBJECT      3
>
>int main(int argc)

This is an incorrect declaration.  Either use

	int main(void)

if you do not need the command line arguments, or

	int main(int argc, char *argv[])	/* or equivalent */

if you do.

-- 
Robert B. Clark
Visit ClarkWehyr Enterprises On-Line at http://www.iquest.net/~rclark/ClarkWehyr.html