Would it be worth opening a Trac bug report or feature request for this? And/or documenting the unexpected behaviour; perhaps here http://haskell.org/haskellwiki/GHC/GUI_programming ? Simon | -----Original Message----- | From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of Duncan | Coutts | Sent: 10 February 2007 11:57 | To: John Ky | Cc: Haskell Cafe | Subject: Re: [Haskell-cafe] GHC throws IOError on Win32 when there is no console | | On Sat, 2007-02-10 at 09:32 +1100, John Ky wrote: | > Hi, | > | > I noticed on Windows that when I use IO functions that write to stdout | > when the process is lacking a console, those functions throw an | > IOError. I'm not sure if this also occurs for stderr because I | > haven't tried it. | > | > Some classes of processes are created without a console because they | > never interact with the user and include System services. Crashing | > with IOError in this case is difficult to diagnose because because the | > only symptom is the process crashes with no visible output. | > | > I believe the most sensible behaviour should be for those functions to | > not throw, but instead do nothing. | | I brought this up some time ago with the GHC developers since it is a | problem for Windows users who use Gtk2Hs and want to hide the console | window. They felt that since this was the default system behaviour that | it's best for GHC not to override that. C programs apparently suffer | from the same problem (possibly depending on the variant of the C lib). | | The situation is much improved from when I originally complained about | this. It does now at least display an message box with the error rather | than silently terminating. | | If there is a reliable way to 'fix' the standard handles (as Paul Moore | suggests) when running without a console then I could include that code | into the Gtk2Hs startup and then make -optl-mwindows the default for | progs compiled with Gtk2Hs. | | Duncan | | _______________________________________________ | Haskell-Cafe mailing list | Haskell-Cafe@haskell.org | http://www.haskell.org/mailman/listinfo/haskell-cafe