getrlimit, setrlimit

[Stephen Weeks]

> I guess I don't see any big advantage of hiding the datatype.  I suppose it
> is slightly more opaque, which is good.

Yeah, that's about it.  It also means we don't have to convert from the datatype
to the int.

> On a style question, what is the argument for the
> 	type t = word
> Note, it is NOT true that this structure is about operations on type t.  If
> any thing, it is about operations on type { hart: t, sort: t}, or of type
> resource. 

Agreed.

> I would like this much better if you just use word instead of t.
> Doesn't this make it more readable?

How about the following?

signature MLTON_RLIMIT =
   sig
      structure Rlim:
	 sig
	    type t = word
	       
	    val infinity: t
	 end

      structure Resource:
	 sig
	    type t
	       
	    val cpuTime: t              (* CPU     CPU time in seconds *)
	    val coreFileSize: t         (* CORE    max core file size *)
	    val dataSize: t             (* DATA    max data size *)
	    val fileSize: t             (* FSIZE   Maximum filesize *)
	    val lockedInMemorySize: t   (* MEMLOCK max locked-in-memory address space *)
	    val numFiles: t             (* NOFILE  max number of open files *)  
	    val numProcesses: t         (* NPROC   max number of processes *)
	    val residentSetSize: t      (* RSS     max resident set size *)
	    val stackSize: t            (* STACK   max stack size *)
	    val virtualMemorySize: t    (* AS      address space (virtual memory) limit *)
	 end
      
      type t = {hard: Rlim.t,
		soft: Rlim.t}

      val get: Resource.t -> t
      val set: t * Resource.t -> unit
   end