https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114805
Bug ID: 114805
Summary: placement new doesn't check array length
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pshevchuk at pshevchuk dot com
Target Milestone: ---
Created attachment 58007
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58007&action=edit
Example code but as attachment
#include <new>
#include <cstdio>
int main()
{
int sz = -1;
char buf[9];
char* res = new (buf) char[sz];
std::puts(res == (char*) nullptr? "correct" : "wrong");
}
This program should output "correct", since:
expr.new.9: array bound is erroneous since it's less than zero before
conversion to std::size_t (9.1)
expr.new.9.5.1: the placement new is nothrow, so the result of this operation
must be nullptr. It isn't
Curiously, if you replace the allocated type with an array of ints, it will
incorrectly throw the std::bad_array_new_length exception instead of returning
nullptr
