diazona / pwait Goto Github PK

Relying on periodic polling is a bad idea in general for a number of reasons:

• With time interval too short, you continuously chew up the system's resources (CPU and RAM) as process constantly wakes up and can not be paged-out even on a busy system
• With time interval too long, there may be a significant delay before you notice the process is gone

What makes this particular example especially dangerous is that, once in a while, a new process may appear with the same PID during the 5 seconds between the checks, and your easy_pwait will never realize it.

The C-code you have does not have any of these problems -- do not devalue it :-)

Modern Linux kernels support pidfd_open() which will result in very simple and very stable implementation if available.

For details, see https://man7.org/linux/man-pages/man2/pidfd_open.2.html

I cannot compile anymore.... there's no such file as sys/capability.h and linux/capability.h doesn't seem to be correct... ?