1/* Retrieve information about a FILE stream.
2   Copyright (C) 2007-2010 Free Software Foundation, Inc.
3
4   This program is free software: you can redistribute it and/or modify
5   it under the terms of the GNU General Public License as published by
6   the Free Software Foundation; either version 3 of the License, or
7   (at your option) any later version.
8
9   This program is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   GNU General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
16
17#include <config.h>
18
19/* Specification.  */
20#include "freading.h"
21
22#include "stdio-impl.h"
23
24/* Don't use glibc's __freading function in glibc < 2.7, see
25   <http://sourceware.org/bugzilla/show_bug.cgi?id=4359>  */
26#if !(HAVE___FREADING && (!defined __GLIBC__ || __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7)))
27
28bool
29freading (FILE *fp)
30{
31  /* Most systems provide FILE as a struct and the necessary bitmask in
32     <stdio.h>, because they need it for implementing getc() and putc() as
33     fast macros.  */
34#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
35  return ((fp->_flags & _IO_NO_WRITES) != 0
36          || ((fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) == 0
37              && fp->_IO_read_base != NULL));
38#elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */
39  return (fp_->_flags & __SRD) != 0;
40#elif defined __EMX__               /* emx+gcc */
41  return (fp->_flags & _IOREAD) != 0;
42#elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw */
43  return (fp->_flag & _IOREAD) != 0;
44#elif defined __UCLIBC__            /* uClibc */
45  return (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) != 0;
46#elif defined __QNX__               /* QNX */
47  return ((fp->_Mode & 0x2 /* _MOPENW */) == 0
48          || (fp->_Mode & 0x1000 /* _MREAD */) != 0);
49#elif defined __MINT__              /* Atari FreeMiNT */
50  if (!fp->__mode.__write)
51    return 1;
52  if (!fp->__mode.__read)
53    return 0;
54# ifdef _IO_CURRENTLY_GETTING /* Flag added on 2009-02-28 */
55  return (fp->__flags & _IO_CURRENTLY_GETTING) != 0;
56# else
57  return (fp->__buffer < fp->__get_limit /*|| fp->__bufp == fp->__put_limit ??*/);
58# endif
59#else
60 #error "Please port gnulib freading.c to your platform!"
61#endif
62}
63
64#endif
65