"Spawning another process" is a very complicated task. There's tons of process state that you need to set before the child starts: process group, file descripto

"Spawning another process" is a very complicated task. There's tons of process state that you need to set before the child starts: process group, file descriptors, signal mask, foreground status, etc. You can try to bundle it all up into a single API like posix_spawn, but the API becomes large and it's hard to cover everything. posix_spawn sure doesn't. fork is an elegant solution to this problem: you can run code as the child, before the child gets to start. I am not aware of any alternative that's as flexible.