1  /* Retrieve information about a FILE stream.
       2     Copyright (C) 2007-2021 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 <stddef.h>
      18  #include <stdio.h>
      19  
      20  /* Assuming the stream STREAM is open for reading:
      21     Return the number of bytes waiting in the input buffer of STREAM.
      22     This includes both the bytes that have been read from the underlying input
      23     source and the bytes that have been pushed back through 'ungetc'.
      24  
      25     If this number is 0 and the stream is not currently writing,
      26     fflush (STREAM) is known to be a no-op.
      27  
      28     STREAM must not be wide-character oriented.  */
      29  
      30  #if HAVE___FREADAHEAD /* musl libc */
      31  
      32  # include <stdio_ext.h>
      33  # define freadahead(stream) __freadahead (stream)
      34  
      35  #else
      36  
      37  # ifdef __cplusplus
      38  extern "C" {
      39  # endif
      40  
      41  extern size_t freadahead (FILE *stream) _GL_ATTRIBUTE_PURE;
      42  
      43  # ifdef __cplusplus
      44  }
      45  # endif
      46  
      47  #endif