is libstdc++ reentrant library?

I am using libstdc++ on MAC for developing extensions for firefox. I am getting crashes inside libstdc+ library when I am referring to it across multiple firefox exte开发者_高级运维nsions. I was thinking whether libstdc++ for XCode compiler is reentrant or not. If not, is there any version of libstdc++ is available with is reentrant ?

See the HOWTO at http://www.cs.huji.ac.il/~etsman/Docs/gcc-3.4-base/libstdc++/html/17_intro/howto.html , specifically the section entitled "The Standard C++ library and multithreading".