sig
val int_of_file_descr : Unix.file_descr -> int
val file_descr_of_int : int -> Unix.file_descr
external _exit : int -> unit = "unix__exit"
external sysconf_open_max : unit -> int = "unix_sysconf_open_max"
external getpgid : int -> int = "unix_getpgid"
val getpgrp : unit -> int
external setpgid : int -> int -> unit = "unix_setpgid"
val setpgrp : unit -> unit
external tcgetpgrp : Unix.file_descr -> int = "unix_tcgetpgrp"
external tcsetpgrp : Unix.file_descr -> int -> unit = "unix_tcsetpgrp"
external ctermid : unit -> string = "unix_ctermid"
external ttyname : Unix.file_descr -> string = "unix_ttyname"
external getsid : int -> int = "unix_getsid"
external setreuid : int -> int -> unit = "unix_setreuid"
external setregid : int -> int -> unit = "unix_setregid"
end