GetExitCodeThread函數是獲得線程的退出碼，
函數：
GetExitCodeThread()
功能：獲取一個結束線程的返回值
函數原形：
BOOL GetExitCodeThread( HANDLE hThread, LPDWORD lpExitCode);
參數：
hThread 指向欲獲取返回值的線程對象的句柄
lpExitCode 用于存儲線程的返回值
返回值：函數執行成功則返回非0值，否則返回
0（FALSE）
第一個參數是線程句柄，用
CreateThread 創建線程時獲得到。
第二個參數是一個 DWORD的指針，用戶應該使用一個 DWORD 類型的變量去接收數據，返回的數據是線程的退出碼，
通過線程退出碼可以判斷線程是否正在運行，還是已經退出。或者可以判斷線程是否是正常退出還是異常退出。
執行成功時，存放線程的狀態碼，如果是線程的返回值，表示線程執行完， 如果線程沒執行完，返回STILL_ACTIVE,如果線程的返回值就是STILL_ACTIVE，就無法判斷 .
MSDN解釋:GetExitCodeThread Function
Retrieves the termination status of the specified thread.
BOOL WINAPI GetExitCodeThread( __in HANDLE hThread, __out LPDWORD lpExitCode );
Parameters
- hThread
-
A handle to the thread.
The handle must have the THREAD_QUERY_INFORMATION access right. For more information, see Thread Security and Access Rights.
- lpExitCode
-
A pointer to a variable to receive the thread termination status. If the specified thread has not terminated and the function succeeds, the termination status returned is STILL_ACTIVE.
Return Value
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
Remarks
If the thread has terminated and the function succeeds, the termination status returned may be one of the following:
- The exit value specified in the ExitThread or TerminateThread function.
- The return value from the thread function.
- The exit value of the thread's process.
Warning If a thread happens to return STILL_ACTIVE (259) as an error code, applications that test for this value could end up in an infinite loop.
參考例子：
1 int main()
2 {
3 DWORD exitCode1 = 0;
4 DWORD exitCode2 = 0;
5 DWORD threadId;
6
7 HANDLE hThrd1 = CreateThread(NULL, 0, ThreadFunc1, 0, 0, &threadId );
9 if (hThrd1)
10 printf("Thread 1 launched\n");
11
13 HANDLE hThrd2 = CreateThread(NULL, 0, ThreadFunc2, 0, 0, &threadId );
14 if (hThrd2)
15 printf("Thread 2 launched\n");
16
18 for (;;)
19 {
20 printf("Press any key to exit..\n");
21 getch();
22 GetExitCodeThread(hThrd1, &exitCode1);
23 GetExitCodeThread(hThrd2, &exitCode2);
24 if ( exitCode1 == STILL_ACTIVE )
25 puts("Thread 1 is still running!");
26
27 if ( exitCode2 == STILL_ACTIVE )
28 puts("Thread 2 is still running!");
29 if ( exitCode1 != STILL_ACTIVE && exitCode2 != STILL_ACTIVE )
30 break;
31 }
32
33 CloseHandle(hThrd1);
34 CloseHandle(hThrd2);
35
36 printf("Thread 1 returned %d\n", exitCode1);
37 printf("Thread 2 returned %d\n", exitCode2);
38 return EXIT_SUCCESS;
39 }
40
41 DWORD WINAPI ThreadFunc1(LPVOID n)
42 {
43 Sleep((DWORD)n*1000*2);
44 return (DWORD)n * 10;
45 }
46
48 DWORD WINAPI ThreadFunc2(LPVOID n)
49 {
50 Sleep((DWORD)n*1000*2);
51 return (DWORD)n * 10;
52 }
posted on 2013-07-31 11:37
王海光 閱讀(5817)
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