Thread: multi proceses

hi,

I want to ask that how 2 processes run in linux. In windows, i preapare a .exe file called prog1.exe (win32 console application), then i create a new .exe called prog2. In prog2 i call(CreateProcess()) prog1.exe as a process. Then when i click prog2.exe, a new window is open and prog2.exe runs in the different window. I want to do the same thing in linux(ubuntu). But in linux i can only run my executable through the terminal. I cd to the directory of my prog1 executable and write ./prog1. If i call prog2 inside of prog1 does it create a new terminal window and runs there? How can i achieve that i call a executable from another executable and a new window appears and both of them run together?

Originally Posted by hkullana

I want to ask that how 2 processes run in linux. In windows, i preapare a .exe file called prog1.exe (win32 console application), then i create a new .exe called prog2. In prog2 i call(CreateProcess()) prog1.exe as a process. Then when i click prog2.exe, a new window is open and prog2.exe runs in the different window. I want to do the same thing in linux(ubuntu). But in linux i can only run my executable through the terminal. I cd to the directory of my prog1 executable and write ./prog1. If i call prog2 inside of prog1 does it create a new terminal window and runs there? How can i achieve that i call a executable from another executable and a new window appears and both of them run together?

Instead of running prog2 directly, you can run it through xterm. This will open a new terminal window with the program running in it:

Code:

system("xterm -e ./prog2 &");

Or if you want, do the fork()/exec() thing instead of using system().

Originally Posted by matsp

Really? I didn't think so... However, I do think that system() waits for the created process to finish before the the owning process gets to run again, so it's not exactly running multiple processes in parallel.

system() goes through the shell. Putting '&' at the end of the command will background it and let system() return.

here is my program

Code:

int main()
{
int pid = fork();

if(pid != 0)
{
cout << "i am the main process" << endl;
}

else
{
cout << "i am the child process" << endl;
}
}

when i cd to the program directory (say my application is "prog"). I write "./prog" without quotes. The it writes:

"i am the main process"
"i am the child process"

in the same terminal. Why does not it opens a new terminal for the child process? how can i achieve that?

Originally Posted by matsp

Yes, if you want a new window, you'll have to start a new xterm, with your "prog2" running inside it.

--
Mats

ok lets say my prog2 is that:

Code:

int main()
{
cout <<"i am the child proccess"<< endl;
return 0;
}

Then my prog1 should call prog2 in new window:

Code:

int main()
{
cout << "i am the parent proccess"<< endl;
....
return 0;
}

can you please fill the empty part in the prog1 source?

or did i get the idea wrong? Should i add something inside of prog2?

thanks,
hkullana

so, is it possible to use semaphores with this type of process calling?

Code:

system("xterm prog2");