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root/usr/lib/libc/stdio/wsetup.c

DEFINITIONS

1. __swsetup

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include "local.h"
  38 /*
  39  * Various output routines call wsetup to be sure it is safe to write,
  40  * because either _flags does not include __SWR, or _buf is NULL.
  41  * _wsetup returns 0 if OK to write, nonzero otherwise.
  42  */
  43 int
__swsetup(fp)
FILE *fp;
  46 {
  47         /* make sure stdio is set up */
  48         if (!__sdidinit)
__sinit();
  51         /*
  52          * If we are not writing, we had better be reading and writing.
  53          */
  54         if ((fp->_flags & __SWR) == 0) {
  55                 if ((fp->_flags & __SRW) == 0)
  56                         return (EOF);
  57                 if (fp->_flags & __SRD) {
  58                         /* clobber any ungetc data */
  59                         if (HASUB(fp))
FREEUB(fp);
fp->_flags &= ~(__SRD|__SEOF);
fp->_r = 0;
fp->_p = fp->_bf._base;
  64                 }
fp->_flags |= __SWR;
  66         }
  68         /*
  69          * Make a buffer if necessary, then set _w.
  70          */
  71         if (fp->_bf._base == NULL)
__smakebuf(fp);
fp->_w = fp->_flags & (__SNBF|__SLBF) ? 0 : fp->_bf._size;
  75         return (0);
  76 }