buffer: add advance(unsigned) back #11993
Conversation
| advance(static_cast<ssize_t>(o)); | ||
| } | ||
|
|
||
| template<bool is_const> |
There was a problem hiding this comment.
I think we have to make the [s]size_t variants advance2. IIRC @jdurgin told me that adding an overloaded function name changes the ABI even for the original call...
There was a problem hiding this comment.
@liewegas i doubt it, because when C++ mangles the method signature it takes its arguments into consideration. let's see if the test passes.
There was a problem hiding this comment.
The issue would be if a user integrated w/ bufferlist in such a way where they are attempting to take the address of the function so that they could invoke it via function pointer -- by adding an overload it now becomes ambiguous and breaks the compilation until it is resolved. Of course, this overloaded parameter change is also ambiguous just by invoking it and would break the compilation of anyone using bufferlist::advance (but linked apps would still work).
There was a problem hiding this comment.
There was a problem hiding this comment.
@dillaman yes and yes.
but is the address of a method really a part of ABI? and i think we should force the user to use the new version, under most circumstances, "the ambiguity" is a bad thing, but in this very case, i think it is helpful.
There was a problem hiding this comment.
okay, the layout changes with this fix. i will revert 053bfa6 then.
quote from https://community.kde.org/Policies/Binary_Compatibility_Issues_With_C%2B%2B#The_Do.27s_and_Don.27ts
add an overload (BC, but not SC: makes &func ambiguous), adding overloads to already overloaded functions is ok (any use of &func already needed a cast).
okay then. seems we need to keep source compatibility. i didn't even take this into consideration actually.
This reverts commit 3caafc4. Fixes: http://tracker.ceph.com/issues/17809 Signed-off-by: Kefu Chai <kchai@redhat.com>
advance(unsigned) and seek(int) were replaced with advance(size_t> and seek(ssize_t) in 053bfa6. this change broke the backward compatibility of librados/librbd's ABI. - deprecates advance(unsigned) and seek(int) - update the callers to use the prefered versions. Fixes: http://tracker.ceph.com/issues/17809 Signed-off-by: Kefu Chai <kchai@redhat.com>
advance(unsigned) and seek(int) were replaced with advance(size_t> and
seek(ssize_t) in 053bfa6. this change broke the backward compatibility
of librados/librbd's ABI.
Fixes: http://tracker.ceph.com/issues/17809
Signed-off-by: Kefu Chai kchai@redhat.com