/* c99array.c
 * example of using variable array parameters to functions.
 * Jon Mayo - PUBLIC DOMAIN - September 11, 2006
 */
/* compile with:
 * gcc t4.c -o t4 -std=c99 -Wall
 *
 * works correctly on:
 * gcc 4.0.3
 */
#include <stdio.h>
#include <stdlib.h>
void xorpattern(unsigned width, unsigned height, unsigned char data[][width]) {
	unsigned x, y;
	printf("data = %d bytes\n", sizeof *data); /* it's a pointer */
	printf("bytes per cell = %d\n", sizeof **data);
	printf("bytes per line = %d\n", sizeof *data);
	for(y=0; y<height; y++) for(x=0; x<width; x++) data[y][x]=y^x;
}

int main() {
	unsigned width=320, height=240;
	unsigned char data[height][width];
	unsigned x, y;

	xorpattern(320, 240, data);

	/* verify */
	for(y=0; y<height; y++) 
		for(x=0; x<width; x++) 
			if(data[y][x]!=(unsigned char)(y^x)) {
				printf("failed at %d,%d\n", x, y);
				return EXIT_FAILURE;
			}

	return 0;
}