Sending a message to parent from child process

[maxorator]

I want my child process (created with createprocess) to send a message to my parent process. Parent process is using a window so I would want my child process to get the handle of the parent process and then use something like sendmessage to parent process...

[Iamien]

If i remember correctly. createprocess has a method of returning the address of the new process.
You pass it a struct pointer to a struct PROCESS_INFORMATION
then read the info in that struct to get the handle of the process so you can send your message.



parameter of the createprocess()

pProcessInformation
[out] Pointer to a PROCESS_INFORMATION structure that receives identification information about the new process.

Handles in PROCESS_INFORMATION must be closed with CloseHandle when they are no longer needed.


Some relevant links..
http://msdn.microsoft.com/library/de...ateprocess.asp
http://msdn.microsoft.com/library/de...mation_str.asp

[Tonto]

Example code that was made very shortly ago:

#include <windows.h>
BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam)
{
	DWORD processId;
	GetWindowThreadProcessId(hwnd, &processId);


	if(lParam == processId)
		PostMessage(hwnd, WM_YOURMESSAGE, 0, 0);
	return TRUE;
}
int main(int argc, char *argv[]) {
	STARTUPINFO         siInfo;
	PROCESS_INFORMATION piInfo;

	ZeroMemory(&siInfo, sizeof(siInfo));
	ZeroMemory(&piInfo, sizeof(piInfo));

	CreateProcess
		("C:\\WINDOWS\\Notepad.exe", "", 0, 0, 
		FALSE, CREATE_DEFAULT_ERROR_MODE, 0, 0, 
		&siInfo, &piInfo);

	WaitForSingleObject(piInfo.hProcess, 1000);
	EnumWindows(&EnumWindowsProc, piInfo.dwProcessId);
	return 0;
}