Re: [boost] [function] Placement new warnings from gcc 6

On 2016-04-02 15:45, Peter Dimov wrote:

Andrey Semashev wrote:

...

Thanks. I've made a patch with a similar idea:

https://github.com/boostorg/function/pull/9

This works, although the following alternative:

template<class T> union function_buffer_ { // as before mutable T data; };

size_t const function_buffer_size = sizeof(function_buffer_<char>);

typedef function_buffer_ function_buffer;

seems slightly more maintainable as it doesn't perform the size computation separately.

That instantiates the template twice, maybe it'll affect compile times. Also, I'm a bit cautious about using an array type in template parameters - maybe it'll cause trouble on ancient compilers? I guess, I could extract all members other than 'data' to a separate union and then: union function_buffer { mutable function_buffer_members m; mutable char data[sizeof(function_buffer_members)]; }; This would require more modifications to the code though. (Sigh... if only we could inherit unions...)