how to use WaitForSingleobject
- by Tyzak
hello in order to try out how to programm with the win32 api i wrote a programm that creates a process.
then i want to check if my proccess waits for the new created process, close the handle and then check waitforsingle obj. again. (the seconde process is sleeping for 700 ms)
first process:
#include <iostream>
#include <windows.h>
#include <string>
using namespace std;
void main()
{
bool ret;
bool retwait;
STARTUPINFO startupinfo;
GetStartupInfo (&startupinfo);
PROCESS_INFORMATION pro2info;
wchar_t wcsCommandLine[] = L"D:\\betriebssystemePRA1PRO2.exe";
ret = CreateProcess(NULL, wcsCommandLine, NULL, NULL, false, CREATE_NEW_CONSOLE, NULL,
NULL, &startupinfo, &pro2info);
cout<<"hProcess: "<<pro2info.hProcess<<endl;
cout<<"dwProcessId: "<<pro2info.dwProcessId <<endl;
if (retwait= WaitForSingleObject (pro2info.hProcess, INFINITE)==true)
cout<<"waitprocess:true"<<endl; //prozess ist fertig
else
cout<<"waitprocess:false"<<endl;
CloseHandle (pro2info.hProcess);//prozesshandle schließen, "verliert connection"
if (retwait= WaitForSingleObject (pro2info.hProcess, INFINITE)==true)//wenn der prozess fertig ist
cout<<"waitprocess:true"<<endl;
else
cout<<"waitprocess:false"<<endl;
//cout<<GetLastError()<<endl; //gibt den letzten fehler aus
ExitProcess(0);
}
seconde process:
#include <iostream>
#include <windows.h>
#include <string>
using namespace std;
void main()
{
int b;
b=GetCurrentProcessId();
cout<<b<<endl;
cout<<"Druecken Sie Enter zum Beenden"<<endl;
cin.get();
//warten bis Benutzer bestätigt
Sleep (700);
ExitProcess(0);
cout<<"test";
}
the first process prints false, false ; but it should print true, false.
instead of the if-else statement is used this:
//switch(WaitForSingleObject (pro2info.hProcess, INFINITE)){
// case WAIT_OBJECT_0: cout << "ja";
// break;
// case WAIT_FAILED:cout << "nein";
// break;
// case WAIT_TIMEOUT:
// break;
//}
// cout<<"waitprocess:true"<<endl;//prozess ist fertig
//else
// cout<<"waitprocess:false"<<endl;
and this seems to work.
what did i wrong with my if-else statement?
thanks in advance
