so does posix_spawn, since you can leak file descriptors into parallel spawning threads/processes before the execve (where they are closed if having O_CLEXEC).
>>matu3b+(OP)
Yeah, that is a problem, and it is totally fixable. Checkout `POSIX_SPAWN_CLOEXEC_DEFAULT` on macOS for an example. Again, just because there are API deficiencies doesn't mean that the idea is wrong.