主要是根据CC_TARGET_PLATFORM宏的值来判断是哪个平台。
以下是CCPlatformConfig.h的内容
#ifndef __BASE_CC_PLATFORM_CONFIG_H__
#define __BASE_CC_PLATFORM_CONFIG_H__
/// @cond DO_NOT_SHOW
/**
Config of cocos2d-x project, per target platform.
THIS FILE MUST NOT INCLUDE ANY OTHER FILE
*/
//////////////////////////////////////////////////////////////////////////
// pre configure
//////////////////////////////////////////////////////////////////////////
// define supported target platform macro which CC uses.
#define CC_PLATFORM_UNKNOWN 0
#define CC_PLATFORM_IOS 1
#define CC_PLATFORM_ANDROID 2
#define CC_PLATFORM_WIN32 3
#define CC_PLATFORM_MARMALADE 4
#define CC_PLATFORM_LINUX 5
#define CC_PLATFORM_BADA 6
#define CC_PLATFORM_BLACKBERRY 7
#define CC_PLATFORM_MAC 8
#define CC_PLATFORM_NACL 9
#define CC_PLATFORM_EMSCRIPTEN 10
#define CC_PLATFORM_TIZEN 11
#define CC_PLATFORM_QT5 12
#define CC_PLATFORM_WINRT 13
// Determine target platform by compile environment macro.
#define CC_TARGET_PLATFORM CC_PLATFORM_UNKNOWN
// mac
#if defined(CC_TARGET_OS_MAC) || defined(__APPLE__)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_MAC
#endif
// iphone
#if defined(CC_TARGET_OS_IPHONE)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_IOS
#endif
// android
#if defined(ANDROID)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_ANDROID
#endif
// win32
#if defined(_WIN32) && defined(_WINDOWS)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_WIN32
#endif
// linux
#if defined(LINUX) && !defined(__APPLE__)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_LINUX
#endif
// marmalade
#if defined(MARMALADE)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_MARMALADE
#endif
// bada
#if defined(SHP)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_BADA
#endif
// qnx
#if defined(__QNX__)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_BLACKBERRY
#endif
// native client
#if defined(__native_client__)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_NACL
#endif
// Emscripten
#if defined(EMSCRIPTEN)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_EMSCRIPTEN
#endif
// tizen
#if defined(TIZEN)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_TIZEN
#endif
// qt5
#if defined(CC_TARGET_QT5)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_QT5
#endif
// WinRT (Windows 8.1 Store/Phone App)
#if defined(WINRT)
#undef CC_TARGET_PLATFORM
#define CC_TARGET_PLATFORM CC_PLATFORM_WINRT
#endif
//////////////////////////////////////////////////////////////////////////
// post configure
//////////////////////////////////////////////////////////////////////////
// check user set platform
#if ! CC_TARGET_PLATFORM
#error "Cannot recognize the target platform; are you targeting an unsupported platform?"
#endif
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WIN32)
#ifndef __MINGW32__
#pragma warning (disable:4127)
#endif
#endif // CC_PLATFORM_WIN32
/// @endcond
#endif // __BASE_CC_PLATFORM_CONFIG_H__