Affected rules

• DCL51-CPP

Description

The rule currently enforces that function names defined in standard library headers are not reused in any namespace. However, a careful re-reading of the C++ standard suggests that's overly specific. [reserved.names] specifically states that the only kinds of name that are reserved are macros, "global names" and "names with external linkage". In [extern.names], the standard says:

Each global function signature declared with external linkage in a header is reserved to the implementation to designate that function signature with external linkage.

So only global function signatures are reserved, and only where they have external linkage. I think we need to do the following:

• Apply only to the global namespace
• Filter list of reserved function names by those that appear in the global namespace and have external linkage (this may already be the case).
• Match function signatures (I believe it is valid to reuse the name as long as the signature is different).

We may also need to review the rules for objects and _ prefixes.

Example

namespace MyNamespace {
  void all_of(); // COMPLIANT
}