Path: utzoo!attcan!uunet!mcvax!hp4nl!philmds!prle!cst!meulenbr
From: meulenbr@cst.UUCP (Frans Meulenbroeks)
Newsgroups: comp.os.minix
Subject: new and improved freopen.c (I hope)
Message-ID: <260@cst.UUCP>
Date: 11 Nov 88 18:41:04 GMT
Reply-To: meulenbr@cst.UUCP (Frans Meulenbroeks)
Organization: Centre for Software Technology, Philips Eindhoven
Lines: 101

Hi!
The current Minix/ST freopen does not do the job properly.
I've hacked my own which is better (I hope).
Feel free to share or improve it. Flames to /dev/null. 
Use at own risk.
The archive is followed by exit and my signature.

Frans Meulenbroeks.

#	This is a shell archive.
#	Remove everything above and including the cut line.
#	Then run the rest of the file through sh.
-----cut here-----cut here-----cut here-----cut here-----
#!/bin/sh
# shar:	Shell Archiver
#	Run the following text with /bin/sh to create:
#	freopen.c
# This archive created: Fri Nov 11 19:40:10 1988
sed 's/^X//' << \SHAR_EOF > freopen.c
X/* new freopen.c for minix/st
X   hacked together: 11/11/88 by F. Meulenbroeks.
X   Disclaimer: almost all of this code is extracted from fopen.c and
X               fclose.c. Use at own risk.
X
X  The problem with the original freopen was that it did not
X  use the same FILE struct to store its values.
X  This results in problems when using code like
X  FILE *yyin = stdin; 
X  which occurs in flex.
X
X  Also freopen should return the original value of stream.
X  This is not the case in the minix/st freopen.
X
X  The original freopen does not neccesarily return the same entry in _io_table
X  if another file is closed before. This causes problems when reopening
X  stderr after closing stdin or stdout (I think).
X
X  I decided the when doing an freopen, one uses the same buffer and
X  buffering method. ANSI C does not explicitly specify this.
X*/
X
X#include <stdio.h>
X
X#define  PMODE    0644
X
XFILE *freopen(name, mode,fp)
Xchar *name , *mode;
XFILE *fp;
X{
X	register int i;
X	int fd, flags;
X
X	for (i=0; i<NFILES; i++)
X		if (fp == _io_table[i]) {
X			break;
X		}
X	if (i >= NFILES)
X		return((FILE *)EOF);
X	flags = fp->_flags;
X	flags = flags & !WRITEMODE & !READMODE;
X	fflush(fp);
X	close(fp->_fd);
X
X	switch(*mode){
X
X	case 'w':
X		flags |= WRITEMODE;
X		if (( fd = creat (name,PMODE)) < 0)
X			return((FILE *)NULL);
X		break;
X
X	case 'a': 
X		flags |= WRITEMODE;
X		if (( fd = open(name,1)) < 0 )
X			return((FILE *)NULL);
X		lseek(fd,0L,2);
X		break;         
X
X	case 'r':
X		flags |= READMODE;	
X		if (( fd = open (name,0)) < 0 )
X			return((FILE *)NULL);
X		break;
X
X	default:
X		return((FILE *)NULL);
X	}
X
X	fp->_count = 0;
X	fp->_fd = fd;
X	fp->_flags = flags;
X	fp->_ptr = fp->_buf;
X	return(fp);
X}
SHAR_EOF
#	End of shell archive
exit 0
-- 
Frans Meulenbroeks        (meulenbr@cst.prl.philips.nl)
	Centre for Software Technology
	( or try: ...!mcvax!philmds!prle!cst!meulenbr)