system()-oputput into a variable

Hello,

I execute a system(..) command and this returns a value which I want to save in a variable.

Code:

---

err = system("rsh -l root 172.16.100.144 pidof tcpdump");

---

I want to save the PID of tcpdump into a variable to use this PID later in my C programme. Is there a possibility to do this?
I know an indirect way with redirecting the output into a file and read this file later. But this is no acceptable solution.

Use popen() instead of system().

Thank you, it works.