Starting a Service

To start a service, the following example opens a handle to an installed database and then specifies the handle in a call to the StartService function. It can be used to start either a service or a driver service, but this example assumes that a service is being started. After starting the service, the program uses the members of the SERVICE_STATUS structure returned by the QueryServiceStatus function to track the progress of the service.

DWORD StartSampleService() 
{ 
    SERVICE_STATUS ssStatus; 
    DWORD dwOldCheckPoint; 
    DWORD dwStartTickCount;
    DWORD dwWaitTime;
    DWORD dwStatus;
 
    schService = OpenService( 
        schSCManager,          // SCM database 
        "Sample_Srv",          // service name
        SERVICE_ALL_ACCESS); 
 
    if (schService == NULL) 
    { 
        MyErrorExit("OpenService"); 
    }
 
    if (!StartService(
            schService,  // handle to service 
            0,           // number of arguments 
            NULL) )      // no arguments 
    {
        MyErrorExit("StartService"); 
    }
    else 
    {
        printf("Service start pending.\n"); 
    }
 
    // Check the status until the service is no longer start pending. 
 
    if (!QueryServiceStatus( 
            schService,   // handle to service 
            &ssStatus) )  // address of status information structure
    {
        MyErrorExit("QueryServiceStatus"); 
    }
 
    // Save the tick count and initial checkpoint.

    dwStartTickCount = GetTickCount();
    dwOldCheckPoint = ssStatus.dwCheckPoint;

    while (ssStatus.dwCurrentState == SERVICE_START_PENDING) 
    { 
        // Do not wait longer than the wait hint. A good interval is 
        // one tenth the wait hint, but no less than 1 second and no 
        // more than 10 seconds. 
 
        dwWaitTime = ssStatus.dwWaitHint / 10;

        if( dwWaitTime < 1000 )
            dwWaitTime = 1000;
        else if ( dwWaitTime > 10000 )
            dwWaitTime = 10000;

        Sleep( dwWaitTime );

        // Check the status again. 
 
        if (!QueryServiceStatus( 
                schService,   // handle to service 
                &ssStatus) )  // address of structure
            break; 
 
        if ( ssStatus.dwCheckPoint > dwOldCheckPoint )
        {
            // The service is making progress.

            dwStartTickCount = GetTickCount():
            dwOldCheckPoint = ssStatus.dwCheckPoint;
        }
        else
        {
            if(GetTickCount()-dwStartTickCount > ssStatus.dwWaitHint)
            {
                // No progress made within the wait hint
                break;
            }
        }
    } 

    if (ssStatus.dwCurrentState == SERVICE_RUNNING) 
    {
        printf("StartService SUCCESS.\n"); 
        dwStatus = NO_ERROR;
    }
    else 
    { 
        printf("\nService not started. \n");
        printf("  Current State: %d\n", ssStatus.dwCurrentState); 
        printf("  Exit Code: %d\n", ssStatus.dwWin32ExitCode); 
        printf("  Service Specific Exit Code: %d\n", 
            ssStatus.dwServiceSpecificExitCode); 
        printf("  Check Point: %d\n", ssStatus.dwCheckPoint); 
        printf("  Wait Hint: %d\n", ssStatus.dwWaitHint); 
        dwStatus = GetLastError();
    } 
 
    CloseServiceHandle(schService); 
    return dwStatus;
}