Namespace question

[Jonathan Wakely]

On 9 March 2017 at 02:49, Gabriel F. T. Gomes wrote:
> Hi,
>
> While working on a refactoring in glibc's libm, I came across a
> question about namespace for some helper functions in math.h.
>
> Each classification macro in math.h, has a type-specific helper
> function, for instance __fpclassifyf for float.  We would like to
> understand if these functions need to be in a namespace or if, since
> they are helper functions, the namespace requirement does not apply.
>
> For instance, is the namespace code in the examples below correct,
> required, or even incorrect?
>
> namespace __c99 {
> extern int __fpclassifyf (float __value);
> extern int __signbit (double __value);
> extern int __isinff (float __value);
> }
>
> namespace std {
> extern int __isinf (double __value);
> }

Libstdc++ doesn't use any of these functions. You can use whatever
private namespaces you want for internal glibc functions.

I would recommend against adding any non-standard functions to
namespace std in the C library headers. The C++ library owns that
namespace and littering it with non-standard names defined outside the
C++ library doesn't seem wise.