https://www.cs.cmu.edu/afs/cs/academic/class/15492-f07/www/pthreads.html
gcc -o join1.o join1.c -lpthread
pthreads tutorial
https://www.cs.cmu.edu/afs/cs/academic/class/15492-f07/www/pthreads.html
gcc -o join1.o join1.c -lpthread
pthreads tutorial