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freopen.c
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1993-06-28
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2KB
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80 lines
/* This is file FREOPEN.C */
/* This file may have been modified by DJ Delorie (Jan 1991). If so,
** these modifications are Coyright (C) 1993 DJ Delorie, 24 Kirsten Ave,
** Rochester NH, 03867-2954, USA.
*/
/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)freopen.c 5.2 (Berkeley) 3/9/86";
#endif LIBC_SCCS and not lint
#include <sys/types.h>
#include <sys/file.h>
#include <stdio.h>
FILE *
freopen(file, mode, iop)
const char *file;
register const char *mode;
register FILE *iop;
{
register f, rw, oflags;
char tbchar;
rw = (mode[1] == '+');
fclose(iop);
switch (*mode) {
case 'a':
oflags = O_CREAT | (rw ? O_RDWR : O_WRONLY);
break;
case 'r':
oflags = rw ? O_RDWR : O_RDONLY;
break;
case 'w':
oflags = O_TRUNC | O_CREAT | (rw ? O_RDWR : O_WRONLY);
break;
default:
return (NULL);
}
if (mode[1] == '+')
tbchar = mode[2];
else
tbchar = mode[1];
if (tbchar == 't')
oflags |= O_TEXT;
else if (tbchar == 'b')
oflags |= O_BINARY;
else
oflags |= (_fmode & (O_TEXT|O_BINARY));
f = open(file, oflags, 0666);
if (f < 0)
return (NULL);
if (*mode == 'a')
lseek(f, (off_t)0, L_XTND);
iop->_cnt = 0;
iop->_file = f;
iop->_bufsiz = 0;
if (rw)
iop->_flag = _IORW;
else if (*mode == 'r')
iop->_flag = _IOREAD;
else
iop->_flag = _IOWRT;
if (oflags & O_TEXT)
iop->_flag |= _IOTEXT;
iop->_base = iop->_ptr = NULL;
return (iop);
}