引自MSDN:
VOID ExitProcess(
UINT uExitCode // exit code for all threads
);
Parameters
uExitCode
Specifies the exit code for the process, and for all threads that are terminated as a result of this call. Use the GetExitCodeProcess function to retrieve the process's exit value. Use the GetExitCodeThread function to retrieve a thread's exit value.
这个uExitCode一般是自己人工终止程序的时候给出的一个信号量,表明什么原因退出进程,这个标志可以人为的约定好的。