Re: [Boost-users] const native arrays at compile time

Subject: Re: [Boost-users] const native arrays at compile time
From: MM (finjulhich_at_[hidden])
Date: 2012-07-12 12:26:20

> -----Original Message-----
> From: boost-users-bounces_at_[hidden] [mailto:boost-users-
> bounces_at_[hidden]] On Behalf Of Nat Linden
> Sent: 12 July 2012 14:05
> To: boost-users_at_[hidden]
> Subject: Re: [Boost-users] const native arrays at compile time
> 
> On Thu, Jul 12, 2012 at 3:07 AM, Hicham Mouline <finjulhich_at_[hidden]>
> wrote:
> 
> > I have a number of questions, some of which are boost specific.
> 
> Hmm, haven't yet spotted the Boost questions.
> 
> > 1. const std::string cols[] = { "col1", "col2", "col3" };
> > Is the const native array cols completely a compile-time construct or
> are
> > std::string objects constructed at runtime?
> > I would guess the latter?
> 
> It would surprise me greatly if any compiler would run library runtime
> code at compile time in order to construct static objects.
> 
> > 2. const char const* cols[] = { "col1", "col2", "col3" };
> > This on the other hand would be pure compile time?
> 
> Yes, should work even in classic C.
> 
> > 3.
> > struct S1 {
> > const char const* cols[]  = { "col1", "col2", "col3" };
> > };
> > struct S2 {
> > const char const* cols[]  = { "colx", "coly", "coly" };
> > };
> >
> > template <typename T>  /// T is either S1 or S2
> > struct S {
> >
> >   const char const* col1s[]  = { "othercol", /// elements of T::cols
> };
> > };
> >
> > Is there a way to build col1s at compile time?
> 
> I confess I'm not sure what you're trying to accomplish here. Wouldn't
> it suffice for the methods of S to directly reference T::cols ?
> _______________________________________________

Because col1s is then passed elsewhere, and it would be nice if it didn't
need to be built at runtime

MM,