Malloc thread safe and compiler versions

[Ian Lance Taylor]

"Brian D. McGrew" <brian@visionpro.com> writes:

> I just read on stackoverflow that if we compile with -pthreads, malloc is
> thread safe on x86 and x86_64 hardware.  Is this true???
>
> If so, what version of gcc/g++ is that implemented in?
>
> We're using CentOS 5.3_x86-64 and gcc-4.1.2-20080704 and about 90% of our
> projects are compiled with g++ using -g -O2.  Functionally speaking, is
> there any reason I should upgrade gcc --- other than just to have the latest
> version?

It's not true, at least not for GNU/Linux.  malloc is thread safe on
GNU/Linux regardless of whether you use -pthread or not.  In any case,
it's really a function of your version of glibc rather than a function
of your gcc.  That is, you should be asking which version of glibc
provides a thread-safe malloc, not which version of gcc.  And the answer
in your case is that the version of glibc you are using has a
thread-safe malloc.

Ian