prog.c: In function ‘job’:
prog.c:19: warning: implicit declaration of function ‘sleep’
prog.c: In function ‘main’:
prog.c:32: warning: control reaches end of non-void function
/home/outB8N/ccWyCt1j.o: In function `main':
prog.c:(.text+0x2e): undefined reference to `sem_init'
prog.c:(.text+0x56): undefined reference to `pthread_create'
/home/outB8N/ccWyCt1j.o: In function `job':
prog.c:(.text+0xa8): undefined reference to `sem_wait'
prog.c:(.text+0xe4): undefined reference to `sem_post'
collect2: ld returned 1 exit status