1 /* Retrieve information about a FILE stream.
2 Copyright (C) 2007-2018 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 <https://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 <https://sourceware.org/bugzilla/show_bug.cgi?id=4359> */
26 #if !(HAVE___FREADING && (!defined __GLIBC__ || defined __UCLIBC__ || __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7)))
27
28 bool
freading(FILE * fp)29 freading (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_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
35 /* GNU libc, BeOS, Haiku, Linux libc5 */
36 return ((fp->_flags & _IO_NO_WRITES) != 0
37 || ((fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) == 0
38 && fp->_IO_read_base != NULL));
39 # elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
40 /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
41 return (fp_->_flags & __SRD) != 0;
42 # elif defined __EMX__ /* emx+gcc */
43 return (fp->_flags & _IOREAD) != 0;
44 # elif defined __minix /* Minix */
45 return (fp->_flags & _IOREADING) != 0;
46 # elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw, MSVC, NonStop Kernel, OpenVMS */
47 # if defined __sun /* Solaris */
48 return (fp_->_flag & _IOREAD) != 0 && (fp_->_flag & _IOWRT) == 0;
49 # else
50 return (fp_->_flag & _IOREAD) != 0;
51 # endif
52 # elif defined __UCLIBC__ /* uClibc */
53 return (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) != 0;
54 # elif defined __QNX__ /* QNX */
55 return ((fp->_Mode & 0x2 /* _MOPENW */) == 0
56 || (fp->_Mode & 0x1000 /* _MREAD */) != 0);
57 # elif defined __MINT__ /* Atari FreeMiNT */
58 if (!fp->__mode.__write)
59 return 1;
60 if (!fp->__mode.__read)
61 return 0;
62 # ifdef _IO_CURRENTLY_GETTING /* Flag added on 2009-02-28 */
63 return (fp->__flags & _IO_CURRENTLY_GETTING) != 0;
64 # else
65 return (fp->__buffer < fp->__get_limit /*|| fp->__bufp == fp->__put_limit ??*/);
66 # endif
67 # elif defined EPLAN9 /* Plan9 */
68 if (fp->state == 0 /* CLOSED */ || fp->state == 4 /* WR */)
69 return 0;
70 return (fp->state == 3 /* RD */ && (fp->bufl == 0 || fp->rp < fp->wp));
71 # else
72 # error "Please port gnulib freading.c to your platform!"
73 # endif
74 }
75
76 #endif
77