ptheard
add -lptheard with gcc warning: implicit declaration of function ‘sleep’ [-Wimplicit-function-declaration] sleep(1); http://stackoverflow.com/questions/14818084/what-is-the-proper-include-for-the-function-sleep-in-c according to man page sleep(3) http://linux.die.net/man/3/sleep http://www.gnu.org/software/coreutils/manual/html_node/sleep-invocation.html#sleep-invocation should add #include <unistd.h>
