The Microsoft-implemented POSIX function name
getpid is a deprecated alias for the _getpid function. By default, it generates Compiler warning (level 3) C4996. The name is deprecated because it doesn't follow the Standard C rules for implementation-specific names. However, the function is still supported.
This API cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported in Universal Windows Platform apps.