As value_from creates a value object, users may want to control the way memory is allocated for it. For this reason the function has an optional storage_ptr parameter, that is used to set the memory_resource for the result.

As the conversion result is set via an output parameter of type value&, the intended storage_ptr is correctly propagated. But users still should take care to not create temporaries using the default memory_resource by accident.

For example, consider this alternative implementation of tag_invoke for ip_address from the section Custom Conversions.

This implementation explicitly creates an array rather than relying on assignment from an initializer list. But the array uses default memory_resource, not the one used by jv.

To avoid creating such temporaries with an incorrect memory_resource, using value's member functions value::emplace_array, value::emplace_object, and value::emplace_string can be helpful.