I have a pthreads program. I have to compile it with gcc -pthread in Linux (-pthreads is unrecognized option) and gcc -pthreads in Sun (-pthread is unrecognized option). Why the difference, since it's the same compiler? However, -lpthread works on both, but I heard this isn't always sufficient.
The Solaris -pthreads and Linux -pthread options do equivalent things. Apparently, gcc-4.x series accepts -pthread for Solaris as well.
You do want the -pthread/-pthreads option while compiling because it adds multithreading support in the preprocessor and the linker.