rm_/lib/freading.h
2020-09-02 16:47:03 +08:00

54 lines
1.9 KiB
C

/* Retrieve information about a FILE stream.
Copyright (C) 2007-2020 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <stdbool.h>
#include <stdio.h>
/* Return true if the stream STREAM is opened read-only, or if the
last operation on the stream was a read operation. Return false if
the stream is opened write-only or append-only, or if it supports
writing and there is no current read operation (such as fgetc).
freading and fwriting will never both be true. If STREAM supports
both reads and writes, then:
- both freading and fwriting might be false when the stream is first
opened, after read encounters EOF, or after fflush,
- freading might be false or true and fwriting might be false
after repositioning (such as fseek, fsetpos, or rewind),
depending on the underlying implementation.
STREAM must not be wide-character oriented. */
#if HAVE___FREADING && (!defined __GLIBC__ || defined __UCLIBC__ || __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
/* Solaris >= 7, Android API >= 29, not glibc >= 2.2, but glibc >= 2.7, or musl libc */
# include <stdio_ext.h>
# define freading(stream) (__freading (stream) != 0)
#else
# ifdef __cplusplus
extern "C" {
# endif
extern bool freading (FILE *stream) _GL_ATTRIBUTE_PURE;
# ifdef __cplusplus
}
# endif
#endif