[Haskell] GHC writes to stderr

Simon Marlow simonmar at microsoft.com
Thu Aug 19 06:31:49 EDT 2004

[ redirected to glasgow-haskell-users at haskell.org ]

On 19 August 2004 08:32, Georg Martius wrote:

> I am just wondering why ghc writes its output to stderr instead of
> stdout. In case of an error it might be reasonably but all the
> ordinary information about chaising and stuff should go to a buffered
> stream I think.   
> Why do I care?
> I start ghc from emacs in a compile window. The output gets displayed
> and in the case of an unbuffered output the display gets updated for
> every single character. I don't have to tell you how slow that is.  

Yes, at some point we need to clean up GHC's messages and make sure
they're all going to the right place.

One issue is that if you write some messages to stdout and some to
stderr, the order gets permuted randomly, which sometimes isn't what you


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