Spawn is a small library exposing only one function:
Spawn.spawn. Its purpose is to start command in the
background. Spawn aims to provide a few missing features of
Unix.create_process such as providing a working directory as well as
improving error reporting and performance.
Errors such as directory or program not found are properly reported as
Unix.Unix_error exceptions, on both Unix and Windows.
On Unix, Spawn uses vfork by default as it is often a lot faster
than fork. There is a benchmark comparing Spawn.spawn to
Unix.create_process in spawn-lib/bench. If you don't trust
vfork, you can set the environment variable SPAWN_USE_FORK to make
Spawn use fork instead.