Error gcc on Linux OS

undefined reference to pthread_create
http://stackoverflow.com/questions/17264984/undefined-reference-to-pthread-create
http://stackoverflow.com/questions/1217705/compiling-c-program-with-posix-aio-lib-on-linux

http://stackoverflow.com/questions/12975232/g-error-pthread-create-and-pointer-to-member-function

http://stackoverflow.com/questions/12975232/g-error-pthread-create-and-pointer-to-member-function