chiark / gitweb /
Only make necessary system calls.
[mLib] / fdflags.c
CommitLineData
aab9ab9f 1/* -*-c-*-
2 *
17119f58 3 * $Id$
aab9ab9f 4 *
5 * Manipulates flags on file descriptors
6 *
7 * (c) 1999 Straylight/Edgeware
8 */
9
10/*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of the mLib utilities library.
13 *
14 * mLib is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
18 *
19 * mLib is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
25 * License along with mLib; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
27 * MA 02111-1307, USA.
28 */
29
aab9ab9f 30/*----- Header files ------------------------------------------------------*/
31
32#include <stdio.h>
33#include <stdlib.h>
34#include <string.h>
35
36#include <fcntl.h>
37
38#include "fdflags.h"
39
40/*----- Main code ---------------------------------------------------------*/
41
42/* --- @fdflags@ --- *
43 *
44 * Arguments: @int fd@ = file descriptor to fiddle with
45 * @unsigned fbic, fxor@ = file flags to set and clear
46 * @unsigned fdbic, fdxor@ = descriptor flags to set and clear
47 *
48 * Returns: Zero if successful, @-1@ if not.
49 *
50 * Use: Sets file descriptor flags in what is, I hope, an obvious
51 * way.
52 */
53
54int fdflags(int fd, unsigned fbic, unsigned fxor,
55 unsigned fdbic, unsigned fdxor)
56{
17119f58 57 int f, ff;
aab9ab9f 58
17119f58 59 if (fbic || fxor) {
60 if ((f = fcntl(fd, F_GETFL)) == -1)
61 return (-1);
62 ff = (f & fbic) ^ fxor;
63 if (f != ff && fcntl(fd, F_SETFL, ff) == -1)
64 return (-1);
65 }
66 if (fdbic || fdxor) {
67 if ((f = fcntl(fd, F_GETFD)) == -1)
68 return (-1);
69 ff = (f & fdbic) ^ fdxor;
70 if (f != ff && fcntl(fd, F_SETFD, ff) == -1)
71 return (-1);
72 }
aab9ab9f 73 return (0);
74}
75
76/*----- That's all, folks -------------------------------------------------*/