lib/freadahead.h

   1 /* Retrieve information about a FILE stream.
   2    Copyright (C) 2007-2024 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 2.1 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 /* This file uses _GL_ATTRIBUTE_PURE, HAVE___FREADAHEAD.  */
  18 #if !_GL_CONFIG_H_INCLUDED
  19  #error "Please include config.h first."
  20 #endif
  21
  22 #include <stddef.h>
  23 #include <stdio.h>
  24
  25 /* Assuming the stream STREAM is open for reading:
  26    Return the number of bytes waiting in the input buffer of STREAM.
  27    This includes both the bytes that have been read from the underlying input
  28    source and the bytes that have been pushed back through 'ungetc'.
  29
  30    If this number is 0 and the stream is not currently writing,
  31    fflush (STREAM) is known to be a no-op.
  32
  33    STREAM must not be wide-character oriented.  */
  34
  35 #if HAVE___FREADAHEAD /* musl libc, Android API level ≥ 33 */
  36
  37 # include <stdio_ext.h>
  38 # define freadahead(stream) __freadahead (stream)
  39
  40 #else
  41
  42 # ifdef __cplusplus
  43 extern "C" {
  44 # endif
  45
  46 extern size_t freadahead (FILE *stream) _GL_ATTRIBUTE_PURE;
  47
  48 # ifdef __cplusplus
  49 }
  50 # endif
  51
  52 #endif