c - Maximum PID in Linux

Question

I am porting an application from Tru64 to Linux and it uses PID_MAX defined in limits.h. Linux doesn't have that define. How do I find PID_MAX in c without reading /proc/sys/kernel/pid_max by hand? Is there a library?

Answer 1

It's 32768 by default, you can read the value on your system in /proc/sys/kernel/pid_max.

And you can set the value higher on 64-bit systems (up to 2²² = 4,194,304) with:

echo 4194304 > /proc/sys/kernel/pid_max

Read more here:

http://www.cs.wisc.edu/condor/condorg/linux_scalability.html (via archive.org)