glibc/manual/examples/memstrm.c

/* open_memstream example.
   Copyright (C) 1991-2021 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 2
   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 <stdio.h>

int
main (void)
{
  char *bp;
  size_t size;
  FILE *stream;

  stream = open_memstream (&bp, &size);
  fprintf (stream, "hello");
  fflush (stream);
  printf ("buf = `%s', size = %zu\n", bp, size);
  fprintf (stream, ", world");
  fclose (stream);
  printf ("buf = `%s', size = %zu\n", bp, size);

  return 0;
}