Re: function attributes on function pointers

[Ian Lance Taylor <iant at google dot com>]

Tim Blechmann <tim@klingt.org> writes:

> is there a way to use function attributes on function pointers?
>
> my program uses a function table for a plugin interface, which includes a 
> function to allocate memory:
>
> void* (*myAlloc)(Host * myHost, size_t size);
>
> is it possible to use the malloc attribute for this to help the optimizer? i was 
> trying something like:
> void* __attribute__ ((malloc))(*myAlloc)(Host * myHost, size_t size);
>
> ... but the attribute will be ignored ...

In general, you can use function attributes on function pointers like
this:

void * (* __attribute__ ((malloc)) my_malloc) (size_t) = malloc;

Unfortunately, this is only supported for some attributes.  It will only
work if the attribute can be attached to a function type rather than to
a specific function declaration.  The malloc attribute is not
implemented in that way, so this does not work for the malloc attribute.

I don't think it would be very difficult to implement this if you are
interested in trying.

Ian