odirect.c

odirect.c (text/plain), 1.74 KB, created by Michael Best on 2002-08-29 17:11:02 UTC

/*****************************************************************************

    odirect - tests O_DIRECT
    Copyright (C) 2002  Wessel Dankers <[e-mail]>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    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

******************************************************************************

    Compile with: gcc -g -O2 -pipe

*****************************************************************************/

#define _GNU_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <malloc.h>

#define BUFSIZE (1<<22)

static int fd;

int main(int argc, char **argv) {
	char *s = 0;
	int i;
	struct stat st;

	if(argc != 2)
		return fprintf(stderr, "Filename expected.\n"), 1;

	fd = open(argv[1], O_WRONLY|O_CREAT|O_TRUNC|O_DIRECT|O_LARGEFILE, 0666);
	if(fd == -1)
		return perror("open()"), 2;

	if(fstat(fd, &st) == -1)
		return perror("stat()"), 2;

	s = memalign(st.st_blksize, BUFSIZE);
	if(!s)
		return perror("memalign()"), 2;

	for(i = 0; i < 128; i++)
		if(write(fd, s, BUFSIZE) != BUFSIZE)
			return perror("write()"), 2;

	if(close(fd))
		return perror("close()"), 2;

	return 0;
}