[Haskell-cafe] invalid character encoding

Duncan Coutts duncan.coutts at worc.ox.ac.uk
Wed Mar 16 08:16:13 EST 2005

On Wed, 2005-03-16 at 13:09 +0000, Duncan Coutts wrote:
> On Wed, 2005-03-16 at 11:55 +0000, Ross Paterson wrote:

> > It doesn't affect functions added by the hierarchical libraries, i.e.
> > those functions are safe only with the ASCII subset.  (There is a vague
> > plan to make Foreign.C.String conform to the FFI spec, which mandates
> > locale-based encoding, and thus would change all those, but it's still
> > up in the air.)
> Hmm. I'm not convinced that automatically converting to the current
> locale is the ideal behaviour (it'd certianly break all my programs!).
> Certainly a function for converting into the encoding of the current
> locale would be useful for may users but it's important to be able to
> know the encoding with certainty. For example some libraries (eg Gtk+)
> take all strings in UTF-8 irrespective of the current locale (it does
> locale-dependent conversions on IO etc but the internal representation
> is always UTF8). We do the conversion to UTF8 on the Haskell side and so
> produce a byte string which we marshal using the FFI CString functions. 

Silly me! There are C marshaling functions that are specified to do just
this but I never noticed them before!

withCAString and similar functions treat haskell Strings as byte


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