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From Ben Laurie <...@algroup.co.uk>
Subject Re: [PATCH] optional hook macros
Date Fri, 06 Feb 2004 12:34:22 GMT
Joe Orton wrote:
> On Fri, Feb 06, 2004 at 10:06:14AM +0000, Ben Laurie wrote:
>>Surely the point is that the function and the function pointer actually 
>>_do_ have compatible types, but we hold the pointer in a variable that 
>>doesn't. That is, we cast it to an incompatible type for storage, then 
>>cast it back.
> The issue is the call to apr_dynamic_fn_register, here's how I read it:
> (((void (*)(const char *, APR_OPTIONAL_FN_TYPE(name) *)) 
>                &apr_dynamic_fn_register)(#name,name))
> this takes a function pointer (&apr_dynamic_fn_register), then casts it
> to a different type (void (*)(const blah blah)), then calls the function
> using this type. That has undefined behaviour, since the type of
> apr_dynamic_fn_register is not compatible with the (void (*)(const blah
> blah) type.

I misunderstood, sorry.



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