不同操作系统相关的宏

1. win32或者win64

_WIN32 Defined as 1 when the compilation target is 32-bit ARM, 64-bit ARM, x86, or x64. Otherwise, undefined.

_WIN64 Defined as 1 when the compilation target is 64-bit ARM or x64. Otherwise, undefined.

#if defined(_WIN32)
#define OS_WINDOWS
#endif

2. linux

#if defined(__linux__)
#define OS_LINUX
#endif

3. macOS

#if defined(__APPLE__)
#define OS_LINUX // macOS does not differ that much from linux
#define OS_MACOS
#endif

4. QNX

__QNX__
The target is a QNX operating system (QNX 4, QNX Neutrino, or BlackBerry PlayBook OS).
__QNXNTO__
The target is the QNX Neutrino RTOS or BlackBerry PlayBook OS.

#if defined(__QNX__)
   /* QNX-specific (any flavor) code here */

   #if defined(__QNXNTO__)
      /* QNX Neutrino-specific code here */
   #else
      /* QNX 4-specific code here */
   #endif
#endif