- pex_run. IN, OUT, ERRDES are each a descriptor, from open_read,
- open_write, or pipe, or they are one of STDIN_FILE_NO,
- STDOUT_FILE_NO or STDERR_FILE_NO; if not STD*_FILE_NO, they
- should be closed. The function should handle the
+ pex_run. IN, OUT, ERRDES, TOCLOSE are all descriptors, from
+ open_read, open_write, or pipe, or they are one of STDIN_FILE_NO,
+ STDOUT_FILE_NO or STDERR_FILE_NO; if IN, OUT, and ERRDES are not
+ STD*_FILE_NO, they should be closed. If the descriptor TOCLOSE
+ is not -1, and the system supports pipes, TOCLOSE should be
+ closed in the child process. The function should handle the