[Python-Dev] Raise OSError or RuntimeError in the OS module?

[Victor Stinner]

Hi,

I introduced recently the signal.pthread_sigmask() function (issue #8407). 
pthread_sigmask() (the C function) returns an error code using errno codes. I 
choosed to raise a RuntimeError using this error code, but I am not sure that 
RuntimeError is the best choice. It is more an OS error than a runtime error: 
should signal.pthread_sigmask() raise an OSError instead?

signal.signal() raises a RuntimeError if setting the signal handler failed. 
signal.siginterrupt() raises also a RuntimeError on error.

signal.setitimer() and signal.getitimer() have their own exception class: 
signal.ItimerError, raised on setimer() and getitimer() error.

Victor