OGG Vorbis：已定义，但未使用 - 如何抑制？

Question

我在学校有一个小组项目（3D FPS 游戏），我使用 C++ 中的 OpenAL 和 OGG Vorbis 编写音频。我们的编译器设置为警告我们已定义但未使用的变量，这被证明是 Vorbis 的一个问题。当我编译我们的应用程序时，我得到了这个：

[  8%] Building CXX object CMakeFiles/fps.dir/src/audio/Sound.cpp.o
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:82:21: warning: ‘OV_CALLBACKS_NOCLOSE’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:89:21: warning: ‘OV_CALLBACKS_STREAMONLY’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:96:21: warning: ‘OV_CALLBACKS_STREAMONLY_NOCLOSE’ defined but not used [-Wunused-variable]
[  9%] Building CXX object CMakeFiles/fps.dir/src/audio/MenuAudioController.cpp.o
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:75:21: warning: ‘OV_CALLBACKS_DEFAULT’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:82:21: warning: ‘OV_CALLBACKS_NOCLOSE’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:89:21: warning: ‘OV_CALLBACKS_STREAMONLY’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:96:21: warning: ‘OV_CALLBACKS_STREAMONLY_NOCLOSE’ defined but not used [-Wunused-variable]
[ 10%] Building CXX object CMakeFiles/fps.dir/src/audio/GameAudioController.cpp.o
In file included from /home/berzeger/FPS/FPS/trunk/game/src/audio/GameAudioController.cpp:1:0:
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:75:21: warning: ‘OV_CALLBACKS_DEFAULT’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:82:21: warning: ‘OV_CALLBACKS_NOCLOSE’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:89:21: warning: ‘OV_CALLBACKS_STREAMONLY’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:96:21: warning: ‘OV_CALLBACKS_STREAMONLY_NOCLOSE’ defined but not used [-Wunused-variable]
[ 11%] Building CXX object CMakeFiles/fps.dir/src/audio/AudioController.cpp.o
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:75:21: warning: ‘OV_CALLBACKS_DEFAULT’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:82:21: warning: ‘OV_CALLBACKS_NOCLOSE’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:89:21: warning: ‘OV_CALLBACKS_STREAMONLY’ defined but not used [-Wunused-variable]
/home/berzeger/FPS/FPS/trunk/game/src/audio/../../include/vorbis/vorbisfile.h:96:21: warning: ‘OV_CALLBACKS_STREAMONLY_NOCLOSE’ defined but not used [-Wunused-variable]

等等。你可以看到这是一团糟，重要的东西很容易丢失。

我似乎无法找到一种方法来抑制 vorbis 未使用的变量。我试过了

#define OV_EXCLUDE_STATIC_CALLBACKS

但这会禁用所有 vorbis 定义，这不是我想要的。

有人可以帮忙吗？提前致谢！

Answer 1

我个人会修改我的构建脚本以过滤掉那些特定的警告，但如果你不喜欢这样做......

您可以创建一个包装头文件，包含包装文件而不是 vorbis 头文件，并在包装​​头文件中使用问题变量，这样警告就会消失。假设它们是整数常量，这样就足够了。

//File: myvorbisfile.h
#include "vorbisfile.h"

// Dummy function in the anonymous namespace 
// to suppress the unused variables
namespace
{
   int hide_unused_variables()
   {
     return 0
      + OV_CALLBACKS_NOCLOSE
      + OV_CALLBACKS_DEFAULT
      ... Fill in the rest ...
    }
}

Answer 2

好的，我想我现在找到了解决方案。我们将头文件复制到我们的应用程序目录中，所以我以这种方式包含 vorbisfile.h：

#include "../../include/vorbis/vorbisfile.h"

当我将这一行更改为：

#include <vorbis/vorbisfile.h>

警告消失了。不知道为什么。