ExitCode

/*

 * ExitCode.c

 *

 * Sample code for "Multithreading Applications in Win32"

 * This is from Chapter 2, Listing 2-2

 *

 * Start two threads and try to exit

 * when the user presses a key.

 */

#define WIN32_LEAN_AND_MEAN

#include <stdio.h>

#include <stdlib.h>

#include <windows.h>

#include <conio.h>

DWORD WINAPI ThreadFunc(LPVOID);

int main()

{

    HANDLE hThrd1;

    HANDLE hThrd2;

    DWORD exitCode1 = 0;

    DWORD exitCode2 = 0;

    DWORD threadId;

    

    hThrd1 = CreateThread(NULL,

        0,

        ThreadFunc,

        (LPVOID)1,

        0,

        &threadId );

    if (hThrd1)

        printf("Thread 1 launched\n");

    hThrd2 = CreateThread(NULL,

        0,

        ThreadFunc,

        (LPVOID)2,

        0,

        &threadId );

    if (hThrd2)

        printf("Thread 2 launched\n");

    // Keep waiting until both calls to

    // GetExitCodeThread succeed AND

    // neither of them returns STILL_ACTIVE.

    // This method is not optimal - we'll

    // see the correct way in Chapter 3.

    for (;;)

    {

int rc1, rc2;

        printf("Press any key to exit..\n");

        _getch();

        rc1 = GetExitCodeThread(hThrd1, &exitCode1);

        rc2 = GetExitCodeThread(hThrd2, &exitCode2);

        if ( exitCode1 == STILL_ACTIVE )

            puts("Thread 1 is still running!");

        if ( exitCode2 == STILL_ACTIVE )

            puts("Thread 2 is still running!");

        if ( exitCode1 != STILL_ACTIVE

            && exitCode2 != STILL_ACTIVE )

            break;

    }

    CloseHandle(hThrd1);

    CloseHandle(hThrd2);

    printf("Thread 1 returned %d\n", exitCode1);

    printf("Thread 2 returned %d\n", exitCode2);

    return EXIT_SUCCESS;

}

/*

 * Take the startup value, do some simple math on it,

 * and return the calculated value.

 */

DWORD WINAPI ThreadFunc(LPVOID n)

{

    Sleep((DWORD)n*1000*2);

    return (DWORD)n * 10;

}

GetExitCodeThread () 함수가 exitcode를 반환(return)할 때, 

thread결과값을 반환할 때와 STILL_ACTIVE인 상태 모두 함수 반환값은 모두 true 이므로 이를 구분해야 한다.

1. thread 종료하여 결과값을 받음

2. thread ACTIVE 상태임

--- 결과 ---

Thread 1 launched

Thread 2 launched

Press any key to exit..

Thread 1 is still running!

Thread 2 is still running!

Press any key to exit..

Thread 1 is still running!

Thread 2 is still running!

Press any key to exit..

Thread 1 is still running!

Thread 2 is still running!

Press any key to exit..

Thread 1 is still running!

Thread 2 is still running!

Press any key to exit..

Thread 1 is still running!

Thread 2 is still running!

Press any key to exit..

Thread 1 is still running!

Thread 2 is still running!

Press any key to exit..

Thread 1 is still running!

Thread 2 is still running!

Press any key to exit..

Thread 1 is still running!

Thread 2 is still running!

Press any key to exit..

Thread 2 is still running!

Press any key to exit..

Thread 2 is still running!

Press any key to exit..

Thread 2 is still running!

Press any key to exit..

Thread 2 is still running!

Press any key to exit..

Thread 2 is still running!

Press any key to exit..

Thread 2 is still running!

Press any key to exit..

Thread 2 is still running!

Press any key to exit..

Thread 2 is still running!

Press any key to exit..

Thread 2 is still running!

Press any key to exit..

Thread 1 returned 10

Thread 2 returned 20