порождать процесс (РАСШИРЕННОЕ РЕАЛЬНОЕ ВРЕМЯ) (spawn a process (ADVANCED REALTIME))
Возвращаемое значение (Return value)
Upon successful completion, posix_spawn() and posix_spawnp()
shall return the process ID of the child process to the parent
process, in the variable pointed to by a non-NULL pid argument,
and shall return zero as the function return value. Otherwise,
no child process shall be created, the value stored into the
variable pointed to by a non-NULL pid is unspecified, and an
error number shall be returned as the function return value to
indicate the error. If the pid argument is a null pointer, the
process ID of the child is not returned to the caller.
