[Haskell-cafe] readFile and closing a file

Henning Thielemann lemming at henning-thielemann.de
Thu Sep 18 11:38:51 EDT 2008

On Wed, 17 Sep 2008, Mitchell, Neil wrote:

> Hi Henning,
> I tend to use openFile, hGetContents, hClose - your initial readFile
> like call should be openFile/hGetContents, which gives you a lazy
> stream, and on a parse error call hClose.

Yes, this seems to be the right way. This weakness should be mentioned in 
the docs of readFile. In production code, you cannot rely on a garbage 
collector to close the file, because you might want to open a file for 
writing after you have processed it with readFile, and there is warranty 
that the file is already closed then.

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