#2480: error function is not lazy
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Reporter: NeilMitchell | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 6.8.3 | Severity: normal
Keywords: | Testcase:
Architecture: Unknown | Os: Windows
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{{{
C:\Neil\Temp>type Test.hs
main = error $ cycle "Hello\n"
C:\Neil\Temp>ghc --make Test.hs
[1 of 1] Compiling Main ( Test.hs, Test.o )
Linking Test.exe ...
C:\Neil\Temp>test
-- hangs forever
}}}
The error message seems to get buffered, which means long/infinite
messages are never displayed. GHCi does evaluate error lazily. The error
function is particularly useful for debugging, which is where I
encountered this problem.
It appears trace has a similar issue of buffering in GHC compiled
programs, but I am not certain.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2480>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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