Example 1 demonstrates how to wrap your library's APIs in a C++ namespace :

// Contents of library.h

namespace library_name
{
    int my_api() { return 42; }
    // ...
}

// Contents of main.cpp

#include <iostream>

int main(void)
{
    using namespace library_name;

    std::cout << "The answer is: " << my_api() << '
';
    return 0;
}

As shown in the preceding example, the contents of the library are wrapped in a namespace and stored in the header (this example demonstrates a header-only library, which is an extremely useful design approach as the end user doesn't have to compile libraries, install them on his/her system, and then link against them). The library user simply includes the library header file and uses the using namespace library_name statement to unwrap the library's APIs. If the user has more than one library with the same API names, this statement can be omitted to remove any ambiguity.