我从Unity网站下载了一个文件
#pragma once
// Standard base includes, defines that indicate our current platform, etc.
#include <stddef.h>
// Which platform we are on?
// UNITY_WIN - Windows (regular win32)
// UNITY_OSX - Mac OS X
// UNITY_LINUX - Linux
// UNITY_IOS - iOS
// UNITY_TVOS - tvOS
// UNITY_ANDROID - Android
// UNITY_METRO - WSA or UWP
// UNITY_WEBGL - WebGL
#if _MSC_VER
#define UNITY_WIN 1
#elif defined(__APPLE__)
#if TARGET_OS_TV //'TARGET_OS_TV' is not defined, evaluates to 0
#define UNITY_TVOS 1
#elif TARGET_OS_IOS //'TARGET_OS_IOS' is not defined, evaluates to 0
#define UNITY_IOS 1
#else
#define UNITY_OSX 1 //'UNITY_OSX' macro redefined
#endif
#elif defined(__ANDROID__)
#define UNITY_ANDROID 1
#elif defined(UNITY_METRO) || defined(UNITY_LINUX) || defined(UNITY_WEBGL)
// these are defined externally
#elif defined(__EMSCRIPTEN__)
// this is already defined in Unity 5.6
#define UNITY_WEBGL 1
#else
#error "Unknown platform!"
#endif
...
问题是，当我试图将该文件包含在我的XCode项目中时，我收到了一个警告(将它们放在注释中(
...
#if TARGET_OS_TV //'TARGET_OS_TV' is not defined, evaluates to 0
#define UNITY_TVOS 1
#elif TARGET_OS_IOS //'TARGET_OS_IOS' is not defined, evaluates to 0
#define UNITY_IOS 1
#else
#define UNITY_OSX 1 //'UNITY_OSX' macro redefined
#endif
...
我尝试使用#pragma warning(suppress: 4101)和一些类似的方法，但它对没有帮助
UPD
...
#ifdef TARGET_OS_TV
#define UNITY_TVOS 1
#elif TARGET_OS_IOS //'TARGET_OS_IOS' is not defined, evaluates to 0
#define UNITY_IOS 1
#else
#define UNITY_OSX 1
#endif
...
使用ifdef有助于消除第一个警告，但第二个警告仍然存在
UPD2
...
#ifdef TARGET_OS_TV
#define UNITY_TVOS 1
#elifdef TARGET_OS_IOS //Invalid preprocessing directive
#define UNITY_IOS 1
#else
#define UNITY_OSX 1
#endif
...
您不应该使用#if来测试未定义的宏。该警告意味着您应该使用#ifdef。
您不能定义以前定义的宏。你可以先定义旧的定义，但这不是一个好主意。
使用ifdef有助于消除第一个警告，但第二个警告仍然存在
在c++23中，您将能够使用#elifdef。
否则，您可以使用#elif defined(the_macro)。