support/xmemstream.h

   1 /* Error-checking wrappers for memstream functions.
   2    Copyright (C) 2016-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef SUPPORT_XMEMSTREAM_H
  20 #define SUPPORT_XMEMSTREAM_H
  21
  22 #include <stdio.h>
  23 #include <sys/cdefs.h>
  24
  25 __BEGIN_DECLS
  26
  27 /* Wrappers for other libc functions.  */
  28 struct xmemstream
  29 {
  30   FILE *out;
  31   char *buffer;
  32   size_t length;
  33 };
  34
  35 /* Create a new in-memory stream.  Initializes *STREAM.  After this
  36    function returns, STREAM->out is a file descriptor open for
  37    writing.  errno is preserved, so that the %m format specifier can
  38    be used for writing to STREAM->out.  */
  39 void xopen_memstream (struct xmemstream *stream);
  40
  41 /* Closes STREAM->OUT.  After this function returns, STREAM->buffer
  42    and STREAM->length denote a memory range which contains the bytes
  43    written to the output stream.  The caller should free
  44    STREAM->buffer.  */
  45 void xfclose_memstream (struct xmemstream *stream);
  46
  47 __END_DECLS
  48
  49 #endif /* SUPPORT_XMEMSTREAM_H */