Error: llroundl cannot be interpreted at compile time, because it has no available source code

[mw]

On Monday, 8 June 2020 at 19:05:45 UTC, Steven Schveighoffer 
wrote:
> On 6/8/20 2:53 PM, mw wrote:
>> And with a symbol-to-c-func table, it should be able to just 
>> call that C func.
>
> Consider that the libc available to the compiler might not be 
> the same as the libc for the target (e.g. cross compilation).
>
> Not just that, but this opens the compiler up to a huge hole of 
> unpredictability and security.

I head that.

But, can we take a pragmatic approach, not the "all-or-none" 
approach as I talked about in the other MI thread: 
(https://forum.dlang.org/post/lsnhqdoyatkzbzqbsrbb@forum.dlang.org)

We can have an approved list of C funcs that allowed to be called 
during CTFE? e.g. math funcs about numbers, but not network or 
string C funcs.

Most people define static const for some numerical values, allow 
C math func at CTFE may solve a large part of the problems 
(80-90%? just my guess).