What difference "--enable-threads=posix" can make

[Muhammad Ali]

Hi All,

I am building gnu 3.1 on mips-sgi-irix-6.5 . I would like to know what the
difference can be if i use the flag "--enable-threads=posix" while running
configure for making gnu. And if I do not use it what is the difference. Can
it make some built in features of C++ like streams and string classes thread
unsafe. If I do not use this. 

Thanks
Muhammad Ali