This API is mainly for Terminal Emulator implementors -- any python program that attempts to determine the printable width of a string on a Terminal. It is certainly possible to use your Operating System's wcwidth() and wcswidth() calls if it is POSIX-conforming, but this would not be possible on non-POSIX platforms, such as Windows, or for alternative Python implementations, such as jython. WWW: https://github.com/jquast/wcwidth