[m-dev.] Socket Library

[Julien Fischer]

On Wed, 20 Oct 2010, Peter Ross wrote:

> Alternatively if you just want to throw an exception from the C code
> directly, write some Mercury code with throws the exception that you
> want and then :- pragma foreign_export it to make it accessible to you
> C code.  Then just call the exported name directly.  eg
>
> :- pred throw_exception(string::in) is erroneous.
> :- pragma foreign_export("C", throw_exception(in), "c_throw_exception").
>
> throw_exception(Msg) :- throw(some_exception_type(Msg)).
>
> Now you can use c_throw_exception("xxx") directly in your C code.

I don't recommmend doing that -- throwing exceptions across the C
interface like that is undefined for the low-level C backend.  (It will
work for the high-level C backend however.)

Julien.
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