The argument dir corresponds the member .dir. The argument env
corresponds to the member .env.
+`child_process_clear`::
+
+ Release the memory associated with the struct child_process.
+ Most users of the run-command API don't need to call this
+ function explicitly because `start_command` invokes it on
+ failure and `finish_command` calls it automatically already.
+
The functions above do the following:
. If a system call failed, errno is set and -1 is returned. A diagnostic