native_client_sdk/src/libraries/nacl_io/log.c

   1 /* Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2  * Use of this source code is governed by a BSD-style license that can be
   3  * found in the LICENSE file. */
   4
   5 #include "nacl_io/log.h"
   6
   7 #include "nacl_io/kernel_wrap_real.h"
   8
   9 #include <alloca.h>
  10 #include <stdarg.h>
  11 #include <stdio.h>
  12 #include <string.h>
  13
  14 void nacl_io_log(const char* format, ...) {
  15   va_list args;
  16   size_t wrote;
  17   char* output;
  18
  19 #ifdef _MSC_VER
  20   /* TODO(sbc): vsnprintf on win32 does not return the
  21    * size of the buffer needed.  This can be implemented
  22    * on win32 in terms of _vscprintf; */
  23 #error "not implemented for win32"
  24 #endif
  25
  26   va_start(args, format);
  27   int len = vsnprintf(NULL, 0, format, args);
  28   va_end(args);
  29   output = alloca(len + 1);
  30
  31   va_start(args, format);
  32   vsnprintf(output, len + 1, format, args);
  33   va_end(args);
  34
  35   _real_write(2, output, strlen(output), &wrote);
  36 }