https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120806
Bug ID: 120806
Summary: std::out_ptr is not conforming to the standard
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: xyb at lotx dot org
Target Milestone: ---
The following code will output the wrong result when using gcc:
```
#include <memory>
#include <print>
int f(int** raw) {
*raw = new int;
return 0;
}
int main() {
std::unique_ptr<int> p;
if (f(std::out_ptr(p)) || !p) {
std::println("p is empty");
} else {
std::println("p is not-empty");
}
}
```
`clang++ -std=c++23 -stdlib=libc++` will output "p is empty".
`cl /std:c++latest` will output "p is empty".
`g++ -std=c++23` will output "p is not empty".
In standard, the adapted smart pointer object will be reset with the result
when the temporary `std::out_ptr_t` is destroyed. In the above code, when `!p`
is evaluated, the temporary object hasn't been destroyed, so the value of `p`
is still empty. The output should be "p is empty".
