Skip to content

Do not define an unnamed namespace in a header file (DCL59-CPP) #552

Description

@nlohmann

The SEI CERT C++ Coding Standard states in DCL59-CPP:

Do not define an unnamed namespace in a header file. When an unnamed namespace is defined in a header file, it can lead to surprising results. Due to default internal linkage, each translation unit will define its own unique instance of members of the unnamed namespace that are ODR-used within that translation unit. This can cause unexpected results, bloat the resulting executable, or inadvertently trigger undefined behavior due to one-definition rule (ODR) violations.

The code currently has one unnamed namespace:

/// namespace to hold default `to_json` / `from_json` functions
namespace
{
constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value;
constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value;
}

I am not sure whether the above problem exists. Maybe @theodelrieu has an idea why we need that namespace in the first place.

Activity

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions