Should I Use `std::` or the Global Namespace When Calling C Functions in C ?

C Headers in C : Namespace Considerations

In the realm of C programming, the inclusion of C headers has often presented a semantic question: should functions be called from the std:: namespace or the global namespace?

Background

C is a subset of C , and as a result, many C functions and headers can be utilized in C with minor modifications. For example, stdio.h becomes cstdio, and stdlib.h becomes cstdlib.

The Question

When working with C headers in C , the choice arises between using functions from std:: or the global namespace. For instance, both printf("Hello world!"); and std::printf("Hello world!"); yield the same output.

Answer

According to the C 11 Standard, C standard library headers with "name.h" behave as if their included names are first placed in the std:: namespace. However, it is unspecified if these names are first declared or defined within the global namespace of std:: and then injected into the global namespace scope.

Therefore, it is recommended to include "cname" headers (e.g., ) and utilize the declarations and definitions from the std:: namespace. If "name.h" headers are required, it's advised to use the declarations and definitions from the global namespace.

Conclusions

In summary, for optimal readability and future-proofing, it is preferable to use the std:: namespace when working with C headers in C . The "cname" headers and the std:: namespace provide explicit and clear indications of the scope of included functions, enhancing code organization and clarity.

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