1 /* Retrieve information about a FILE stream. 2 Copyright (C) 2007, 2009-2021 Free Software Foundation, Inc. 3 4 This file is free software: you can redistribute it and/or modify 5 it under the terms of the GNU Lesser General Public License as 6 published by the Free Software Foundation; either version 3 of the 7 License, or (at your option) any later version. 8 9 This file 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 Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public License 15 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 16 17 #include <stdbool.h> 18 #include <stdio.h> 19 20 /* Return true if the stream STREAM is opened write-only or 21 append-only, or if the last operation on the stream was a write 22 operation. Return false if the stream is opened read-only, or if 23 it supports reading and there is no current write operation (such 24 as fputc). 25 26 freading and fwriting will never both be true. If STREAM supports 27 both reads and writes, then: 28 - both freading and fwriting might be false when the stream is first 29 opened, after read encounters EOF, or after fflush, 30 - freading might be false or true and fwriting might be false 31 after repositioning (such as fseek, fsetpos, or rewind), 32 depending on the underlying implementation. 33 34 STREAM must not be wide-character oriented. */ 35 36 #if HAVE___FWRITING 37 /* glibc >= 2.2, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.34, Android API >= 29, musl libc */ 38 39 # if HAVE_STDIO_EXT_H 40 # include <stdio_ext.h> 41 # endif 42 # define fwriting(stream) (__fwriting (stream) != 0) 43 44 #else 45 46 # ifdef __cplusplus 47 extern "C" { 48 # endif 49 50 extern bool fwriting (FILE *stream) _GL_ATTRIBUTE_PURE; 51 52 # ifdef __cplusplus 53 } 54 # endif 55 56 #endif