On 16 August 2017 at 15:40, Jonathan Wakely wrote: > On 16 August 2017 at 15:27, Oleg Endo wrote: >> On Wed, 2017-08-16 at 13:30 +0200, Paolo Carlini wrote: >>> >>> I didn't understand why we don't already handle the easy case: >>> >>> constexpr int* ptr = nullptr; >>> delete ptr; >>> >> >> What about overriding the global delete operator with some user defined >> implementation? Is there something in the C++ standard that says the >> invocation can be completely omitted, i.e. on which side of the call >> the nullptr check is being done? >> >> One possible use case could be overriding the global delete operator to >> count the number of invocations, incl. for nullptr. Not sure how >> useful that is though. > > Users can replace the deallocation function "operator delete" but this > is the delete operator ... a subtly different thing. > > Anyway, the standard says: > > "If the value of the operand of the delete-expression is a null > pointer value, it is unspecified whether a deallocation function will > be called as described above." > > So it's permitted to omit the call to operator delete.
Before C++11 the call was required: "The delete-expression will call a deallocation function (3.7.3.2)." This was changed by http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#348
