[MLton] Some issues with MLton on MinGW
fluet at tti-c.org
Sat Mar 3 11:00:44 PST 2007
> I am trying to port a large application from SML/NJ to MLton.
> The final product needs to be a standalone application on Windows,
> which is why we need to use the MinGW (not Cygwin) port of MLton.
> Stephen Weeks had been working on porting this for some time and
> gotten quite far and I am picking up where he left and trying to
> complete the job. All in all this is progressing quite well
> although there were some problems along the way which I would like
> to share so that they maybe can get fixed.
If you have additional changes that you've made for use under MinGW, it
would be great if we could put them into the repository. Then everyone
is on the same page with regards to changes.
> - When trying to compile MLton on MinGW, I ran into the following
> Error: ..\lib\mlton\basic\vector.sml 10.29.
> Variable type in structure disagrees with argument signature.
> variable: unfoldi
> structure: _ -> [ 'a t ]
> signature: _ -> [ 'a t * 'b ]
> I was able to work around this issue by Hand-propagating changes
> to unfoldi in Vector and Array structures as suggested in
I think, though, that this is a general problem with changes since the
last release. We should add an upgrade-basis check to handle old
versions of MLton.Vector.unfoldi.
> - The program I am trying to compile is rather large. During
> compilation (on Linux nad MinGW) I ran into the following errors:
> "numPeeks overflow" and "numLinks overflow".
> I was able to work around these by commenting out the lines in
> lib/mlton/basic/property-list.fun that increase the numPeeks and
> numLinks values (a suggestion by Stephen Weeks)
Large indeed. I think Vesa is correct that Overflow sometimes signals a
compiler bug. It would be useful to verify that such is not the case in
> - OS.FileSys.tmpName() returns a unix-style filename (e.g. /tmp/abcde)
> which on Windows most likely is not a good temporary filename
> (unless the user by chance has a \tmp directory on the current drive)
> The return value really should be one in a native Windows temporary
It seems like we can just implement tmpName with a case on the platform
using C:\TEMP\* for windows systems.
> - INetSock.any() and INetSock.toAddr() produce a
> "SysErr: Invalid argument [inval]" error when called.
> After trying the modifications suggested in
> the conversion still does not work. The htons function seems to
> not be called correctly (as suggested in
> http://mlton.org/cgi-bin/viewsvn.cgi?rev=4333&view=rev )
Yes, as those notes say, I'm not at all sure that the endian changes are
being applied at the right time or to the right values. It would be
really useful for someone with more network programming experience to
look through the implementation.
> - After working around the INetSock.toAddr() issue, I found that
> neither function Socket.acceptNB() (to check whether a connection
> is requested without blocking) nor Socket.select() (to wait until
> a connection request arrives or a timeout expires) appear to
> be currently implemented. Without either of the two I don't see
> any way to accept a connection without blocking the whole
> application for an indefinite amount of time. Does anybody know
> a workaround for this?
> - On the other end, Socket.connect does not appear to work either.
> Calling it results in an
> "unhandled exception: SysErr: No error [<UNKNOWN>]"
> Although this might just be a problem of trying to connect to the
> wrong port due to the htons function problem. Although the
> server listening on the other end is just a SML program compiled
> with the same MLton as the client, so the port number mangling
> should be the same in both cases. Note that all of this is on
> MinGW under Windows -- it might work fine on Unix/Linux.
I don't have any immediate suggestions.
It would be nice to know if things do work fine on Unix/Linux; if it
does not, then we'd at least know that it is a pervasive problem with
the Basis Library implementation, rather than just a platform
Also, since your application works under SML/NJ, it wouldn't be a bad
idea to look at the SML/NJ sources to see how they implement these
functions on Windows. (Though, I believe that they avoid MinGW altogether.)
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