1/* Retrieve information about a FILE stream.
2   Copyright (C) 2007 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/* Don't use glibc's __freading function in glibc < 2.7, see
23   <http://sourceware.org/bugzilla/show_bug.cgi?id=4359>  */
24#if !(HAVE___FREADING && (!defined __GLIBC__ || __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7)))
25
26bool
27freading (FILE *fp)
28{
29  /* Most systems provide FILE as a struct and the necessary bitmask in
30     <stdio.h>, because they need it for implementing getc() and putc() as
31     fast macros.  */
32#if defined _IO_ferror_unlocked     /* GNU libc, BeOS */
33  return ((fp->_flags & _IO_NO_WRITES) != 0
34	  || ((fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) == 0
35	      && fp->_IO_read_base != NULL));
36#elif defined __sferror             /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */
37  return (fp->_flags & __SRD) != 0;
38#elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, mingw */
39  return (fp->_flag & _IOREAD) != 0;
40#elif defined __UCLIBC__            /* uClibc */
41  return (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) != 0;
42#elif defined __QNX__               /* QNX */
43  return ((fp->_Mode & 0x2 /* _MOPENW */) == 0
44	  || (fp->_Mode & 0x1000 /* _MREAD */) != 0);
45#else
46 #error "Please port gnulib freading.c to your platform!"
47#endif
48}
49
50#endif
51