[Bug libstdc++/86954] redundant nothrow in call of ::operator delete
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86954 --- Comment #4 from frankhb1989 at gmail dot com --- Well, actually I'm not sure if the original implementation has done the right thing, as I don't find that the standard has requirement to specify that the replaced definitions must acknowledge the fact nothrow_t overloads should only be called on the specified condition (... and if so, whether it worth an LWG issue). But that still seems suspicious to me, because symmetry of call between nothrow_t placement ::operator new and ::operator delete does not exist in the language indeed, so that seems like an unintentional use unless it is documented elsewhere. On the other hand, the change here towards to a simpler and undoubtedly conformant way. BTW, I do know the feature is deprecated in C++17 and removed in C++2a. I read the paper of deprecation. It is plausible to be removed from the standard, but not a must - not with a very strong reason. However, I am sure I do need that feature so I have to reinvent my wheels... as done internally by various standard library implementations. (More specifically, I need std::_Temporary_buffer in libstdc++ and MSVC's current implementation, or at least something equivalent to std::__return_temporary_buffer in libc++, but surely I can't rely on them directly.) At least a raw call of allocation function does not always express the intended call site requirements clearly like std::get_temporary_buffer, so users who want to make it clear have to afford the extra layer of an abstraction. Arguably, the removal will bloat work for anyone wants that and discourage clearer expression of intentions.
[Bug libstdc++/86954] redundant nothrow in call of ::operator delete
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86954 Jonathan Wakely changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution|--- |FIXED Target Milestone|--- |9.0 --- Comment #3 from Jonathan Wakely --- On the other hand, with PR 68210 fixed the change is harmless. So fixed on trunk. Not suitable for backports though.
[Bug libstdc++/86954] redundant nothrow in call of ::operator delete
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86954 --- Comment #2 from Jonathan Wakely --- Author: redi Date: Tue Aug 14 20:19:20 2018 New Revision: 263542 URL: https://gcc.gnu.org/viewcvs?rev=263542&root=gcc&view=rev Log: PR libstdc++/86954 use non-placement operator delete As explained in the PR, there's no reason to call the nothrow delete, we can just use the normal one. PR libstdc++/86954 * include/bits/stl_tempbuf.h (return_temporary_buffer): Use non-placement delete. Modified: trunk/libstdc++-v3/ChangeLog trunk/libstdc++-v3/include/bits/stl_tempbuf.h
[Bug libstdc++/86954] redundant nothrow in call of ::operator delete
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86954 --- Comment #1 from Jonathan Wakely --- Arguably this was good defensive programming for C++03. The program could have replaced operator new(size_t) and operator delete(void*) but not replaced operator new(size_t, const nothrow_t&) and operator delete(void*, const nothrow_t&). That would be undefined (C++03 [lib.new.delete.single] p7) but by using the nothrow version of operator delete the library avoids mixing the default version of new with a replaced version of delete. LWG 206 changed the behaviour for C++11, so that combining the nothrow new and normal delete does the right thing, but GCC has only met that requirement since yesterday. I'm not sure it's worth changing anything here now. get_temporary_buffer was deprecated and removed from C++2a anyway.
