extension module, thread safety?

[Torsten Mohr]

Hi,

i write an extension module in C at the moment.  This
module does some work on some own data types that
consist of some values.
The functions that can change the data are written in C.

The question came up if this is by itself thread safe,
if some two or more threads try to change these data types,
are the C functions by themselves are "atomic" or can they
be interrupted be the perl interpreter and then (data types
are in some inconsistent half-changed state) another function
that works on these data is called?


Thanks for hints,
Torsten.