mdw@git.distorted.org.uk Git - mLib/blob - sys/fdflags.c

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