Am 05.05.2016 um 01:55 hat Eric Blake geschrieben: > I was thrown by the fact that the public type BlockRequest had > an anonymous union, but no obvious discriminator. Turns out > that the only client of the second branch of the union was code > internal to io.c, and that with a slight abuse of QEMUIOVector* > to pass a void* pointer, we can make the public interface less > confusing. > > (Yes, I know that strict C doesn't guarantee that you can cast > void* to the wrong type and then back to void* - it only > guarantees the reverse direction of the original pointer to > void* and back to the original type - but we already have other > assumptions throughout the qemu code base that assume that all > pointers are interchangeable in representation). > > Signed-off-by: Eric Blake <[email protected]>
Do you really think abusing fields makes things clearer than using a union? We could just add comments instead that tell which branch is used for what. And after my patch "block: Remove bdrv_aio_multiwrite()", I think the struct isn't part of a public interface any more anyway. Kevin
