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_PROCESS structure returned by the QueryServiceStatusEx function to track the progress of the service.

The function requires a handle to a service control manager database. For more information, see Opening an SCManager Database.

#include <windows.h>#include <stdio.h>BOOL StartSampleService(SC_HANDLE schSCManager) {     SC_HANDLE schService;    SERVICE_STATUS_PROCESS ssStatus;     DWORD dwOldCheckPoint;     DWORD dwStartTickCount;    DWORD dwWaitTime;    DWORD dwBytesNeeded;     schService = OpenService(         schSCManager,          // SCM database         "Sample_Srv",          // service name        SERVICE_ALL_ACCESS);      if (schService == NULL)     {         return 0;     }     if (!StartService(            schService,  // handle to service             0,           // number of arguments             NULL) )      // no arguments     {        return 0;     }    else     {        printf("Service start pending./n");     }     // Check the status until the service is no longer start pending.      if (!QueryServiceStatusEx(             schService,             // handle to service             SC_STATUS_PROCESS_INFO, // info level            &ssStatus,              // address of structure            sizeof(SERVICE_STATUS_PROCESS), // size of structure            &dwBytesNeeded ) )              // if buffer too small    {        return 0;     }     // 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 (!QueryServiceStatusEx(             schService,             // handle to service             SC_STATUS_PROCESS_INFO, // info level            &ssStatus,              // address of structure            sizeof(SERVICE_STATUS_PROCESS), // size of structure            &dwBytesNeeded ) )              // if buffer too small            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;            }        }    }     CloseServiceHandle(schService);     if (ssStatus.dwCurrentState == SERVICE_RUNNING)     {        printf("StartService SUCCESS./n");         return 1;    }    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);         return 0;    } }