how do you like the name "lifetimebound" instead?

Jul 22, 2025 8:16:03 PM Frederick Virchanza Gotham via Std-Proposals <std-proposals_at_[hidden]>:

> On Tue, Jul 22, 2025 at 1:38 PM Jan Schultke wrote:
>>
>> Another way to use the c_str() member function you've mentioned,
>> without involving a variable would be:
>>
>>> void f(const char*);
>>> wxString mystr( wxS("Hello I'm a monkey") );
>>> f(mystr.c_str());
>
>
> We want an attribute to express the following:
>
> "The object returned from this function can generate handles that
> become invalid when the object is destroyed (i.e. the generated handle
> does not out-live the object). Therefore, if you use the returned
> object to generate a handle, then you must ensure that the object is
> still in existence when the handle is used. To ensure this, either (a)
> store the object in a local variable, or (b) use any generated handles
> before the full expression is evaluated.".
>
> I think we would need a pair of attributes to make this work. For
> instance 'wxString' would need a method marked as 'must_store':
>
> struct wxString {
> [[must_store]] wxCStr c_str(void) const;
> };
>
> And the the class 'wxCStr' would need to mark a method to indicate
> that it generates a handle that does not out-live the object:
>
> struct wxCStr {
> [[generates_temporary_handle]] operator wchar_t const *(void) const;
> };
>
> Actually on second thought, if "wxCStr::operator wchar_t*" is marked
> as [[generates_temporary_handle]], then maybe "wxString::c_str"
> doesn't need to be marked at all. Actually I think the marking in the
> 'wxCStr' class is enough.
>
> So forget about [[must_store]]. Instead I'd like to propose
> [[generates_temporary_handle]].
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