Maximum PID in Linux

c linux pid
Alexander Stolz picture Alexander Stolz · Jun 9, 2011 · Viewed 64k times · Source

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

Exos picture Exos · Jun 9, 2011

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)

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