CreateProcess problem

[poda]

Hi Friends, I need to invoke a .exe file and pass a message to that file. Using CreateProcess,I invoked(called) the exe file, FindWindow API to get the invoked exe and SendMessage to send the message. The problem is, there is a time delay in CreateProcess that the FindWindow API cannot find it,if WaitForSingleObject() function is not used. CreateProcess("C:\\Bin\\wfp.exe",NULL,0,0,FALSE,CREATE_NEW_CONSOLE,0,0,&si,&pi); WaitForSingleObject(pi.hThread,500);//delay time 500ms CloseHandle(pi.hProcess); hExeWnd=FindWindow(NULL,"WFP"); if(hExeWnd) { ::SendMessage(hExeWnd,WM_PLOTWAVE,0,0); ShowWindow(hExeWnd,SW_SHOW); } The delay time 500ms may vary from machine to machine in accordance with its performance.If I give it as INFINITE,the program stops there UNTILL the wfp.exe window is CLOSED,which is unacceptable. So how can I make the program to wait untill the CreateProcess() completes its task in executing the exe. NOTE:I tried using ShellExecute API,but there too Sleep() function is needed for the time delay.

[Michael Dunn]

Check out WaitForInputIdle()

--Mike-- Visual C++ MVP :cool: LINKS~! Ericahist | PimpFish | CP SearchBar v3.0 | C++ Forum FAQ

[Naveen]

if both parent application and child is urs, u can implement another technique. Create a named event in both application. The parent application, after calling the createprocess should wait for this event. The child process may set the event to signalled state after initialized.

nave

[poda]

Thanks friends! I cannot use WaitForInputIdle() since it also requires the time delay. I tried using Naveen's idea of creating events. It worked! In the Parent application,I wrote as HANDLE hEvent; hEvent=CreateEvent(NULL,FALSE,FALSE,"WFP_EVENT");//Named Event CreateProcess("C:\\Bin\\wfp.exe",NULL,0,0,FALSE,CREATE_NEW_CONSOLE,0,0,&si,&pi); //Wait till the Event is Signaled from the called child application WaitForSingleObject(hEvent,INFINITE); CloseHandle(pi.hProcess); CloseHandle(hEvent); In the child application(i.e the called Exe) BOOL CWFPDlg::OnInitDialog() { ... HANDLE hEvent; hEvent=CreateEvent(NULL,FALSE,FALSE,"WFP_EVENT"); if(GetLastError()==ERROR_ALREADY_EXISTS) { hEvent=OpenEvent(EVENT_MODIFY_STATE,FALSE,"WFP_EVENT"); SetEvent(hEvent);//Signal the event } ... }

[Naveen]

poda123 wrote:

if(GetLastError()==ERROR_ALREADY_EXISTS) { hEvent=OpenEvent(EVENT_MODIFY_STATE,FALSE,"WFP_EVENT");

why r u openeing the event again. u already have the handle of the event?I think u can skip that line..

nave

[poda]

Hey... WaitForInputIdle() also works,if I specify the delay time as INFINITE. Great! Thanks a lot. Thank you!

[poda]

That's right! Thank you!