/* nonblock_fcntl.c -- Set nonblocking mode using fcntl()
 $Id: nonblock_fcntl.c,v 1.3 2000/12/08 03:26:23 jackson Exp $
 
 * Copyright (c) 1998-2000 Carnegie Mellon University.  All rights reserved.
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 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any other legal
 *    details, please contact  
 *      Office of Technology Transfer
 *      Carnegie Mellon University
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 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
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#include <config.h>
#include <sys/types.h>
#include <sys/file.h>
#include <fcntl.h>

#include "xmalloc.h"
#include "exitcodes.h"
#include "nonblock.h"

#ifndef	FNDELAY
#define FNDELAY		O_NDELAY
#endif

#ifdef O_NONBLOCK
#define NON_BLOCKING_MODE O_NONBLOCK
#else
#define NON_BLOCKING_MODE FNDELAY
#endif

/*
 * Modifies the non-blocking mode on the file descriptor 'fd'.  If
 * 'mode' is nonzero, sets non-blocking mode, if 'mode' is zero
 * clears non-blocking mode.
 */
void
nonblock(fd, mode)
int fd;
int mode;
{
    int flags;

    flags = fcntl(fd, F_GETFL, 0);
    if (flags < 0) fatal("Internal error: fcntl F_GETFL failed", EC_IOERR);
    if (mode) {
	flags |= NON_BLOCKING_MODE;
    }
    else {
	flags &= ~NON_BLOCKING_MODE;
    }
    fcntl(fd, F_SETFL, flags);
}
