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(3DFPS游戏)，我用C++中的OpenAL和OGG Vorbis编写音频程序。我们的编译器被设置为警告我们已定义的变量，但没有使用变量，这是Vorbis的问题。当我编译我们的应用程序时，我得到这样的结果：

[  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]

诸若此类。你可以看到这是一片混乱，重要的东西很容易丢失。

我似乎找不到一种方法来抑制vorbis未使用的变量。我试过了

#define OV_EXCLUDE_STATIC_CALLBACKS

但这会禁用所有的vorbis定义，这不是我想要的。

有人能帮帮忙吗？提前感谢！

Answer 1

好了，我想我现在找到解决方案了。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了VOUBISFILE.h：

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

当我将此行更改为：

#include <vorbis/vorbisfile.h>

警告消失了。不知道为什么。

Answer 2

就我个人而言，我会修改我的构建脚本来过滤掉那些特定的警告，但是如果你不想这样做的话……

您可以创建一个包装器头文件，包括包装器文件而不是vorbis头文件，并在包装器头中使用问题变量，这样警告就会消失。假设它们是整数常量，这样的东西应该就足够了。

//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 ...
    }
}