如何检查外部调用程序的状态

CreateProcess
The CreateProcess function creates a new process and its primary thread. The new process executes the specified executable file.

BOOL CreateProcess(  LPCTSTR lpApplicationName,// pointer to name of executable module 
        LPTSTR lpCommandLine, // pointer to command line string 
        LPSECURITY_ATTRIBUTES lpProcessAttributes,  // process security attributes 
        LPSECURITY_ATTRIBUTES lpThreadAttributes,  // thread security attributes 
        BOOL bInheritHandles,  // handle inheritance flag 
        DWORD dwCreationFlags, // creation flags 
        LPVOID lpEnvironment,  // pointer to new environment block 
        LPCTSTR lpCurrentDirectory,  // pointer to current directory name 
        LPSTARTUPINFO lpStartupInfo,  // pointer to STARTUPINFO 
        LPPROCESS_INFORMATION lpProcessInformation  // pointer to PROCESS_INFORMATION);

先用这个函数打开程序，再用最后一个参数中的 dwProcessId 作为参数，调用OpenProcess 就可以知道进程是否退出。
typedef struct _PROCESS_INFORMATION {
        // pi   
        HANDLE hProcess;   
        HANDLE hThread;   
        DWORD dwProcessId;   
        DWORD dwThreadId;
} PROCESS_INFORMATION;

另外，CreateProcess 的返回值如下

Return ValuesIf the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call [url=mkMSITStore:C:\Program%20Files\Microsoft%20Visual%20Studio\MSDN98\98VS\2052\winbase.chm::/devdoc/live/pdwbase/errors_3uwi.htm]GetLastError[/url].

当返回值为0的时候，证明函数执行错误，可以使用GetLastError获得更多的信息。