Re: [boost] Formal Review of Proposed Boost.Histogram Library Starts TODAY

Subject: Re: [boost] Formal Review of Proposed Boost.Histogram Library Starts TODAY
From: Gavin Lambert (boost_at_[hidden])
Date: 2018-09-19 01:20:24

On 19/09/2018 11:26, Steven Watanabe wrote:
> On 09/18/2018 05:17 PM, Gavin Lambert wrote:
>> Steven's already addressed this as well, which seems to agree.  Although
>> I must admit a little surprise; I thought I remembered that even though
>> the actual initialisation of members occurs in the defined order,
>> evaluation of arguments to the initialisers might not be.  Perhaps this
>> was something tightened in C++11?
> 
> It was always that way:
> 
> "There is a sequence point (1.9) after the initialization
> of each base and member. The expression-list of a
> mem-initializer is evaluated as part of the initialization
> of the corresponding base or member." [C++03]

Correct me if I'm wrong, but that text does not appear in C++98.  So 
it's not quite "always". :)

Although C++98 does still require that base constructors are called 
first [class.base.init#5] and that it is legal to call instance methods 
in the initialisers for members (but not legal in the base constructor 
call itself) [class.base.init#8].  So that part has probably always been 
safe.