1 /* Retrieve information about a FILE stream.
2 Copyright (C) 2007-2021 Free Software Foundation, Inc.
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.
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.
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/>. */
20 /* Return true if the stream STREAM is opened read-only, or if the
21 last operation on the stream was a read operation. Return false if
22 the stream is opened write-only or append-only, or if it supports
23 writing and there is no current read operation (such as fgetc).
25 freading and fwriting will never both be true. If STREAM supports
26 both reads and writes, then:
27 - both freading and fwriting might be false when the stream is first
28 opened, after read encounters EOF, or after fflush,
29 - freading might be false or true and fwriting might be false
30 after repositioning (such as fseek, fsetpos, or rewind),
31 depending on the underlying implementation.
33 STREAM must not be wide-character oriented. */
35 #if HAVE___FREADING && (!defined __GLIBC__ || defined __UCLIBC__ || __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
36 /* Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.34, Android API >= 29, not glibc >= 2.2, but glibc >= 2.7, or musl libc */
39 # include <stdio_ext.h>
41 # define freading(stream) (__freading (stream) != 0)
49 extern bool freading (FILE *stream) _GL_ATTRIBUTE_PURE;