C++ Primer Plus

Namespaces and the Future

As programmers become more familiar with namespaces, common programming idioms will emerge. Here are some current guidelines:

• Use variables in a named namespace instead of using external global variables.

• Use variables in an unnamed namespace instead of using static global variables.

• If you develop a library of functions or classes, place them in a namespace. Indeed, C++ currently already calls for placing standard library functions in a namespace called std. This extends to functions brought in from C. For example, the math.c header file, which is C-compatible, doesn’t use namespaces, but the C++ cmath header file should place the various math library functions in the std namespace.

• Use the using directive only ...