public enum InputPurpose
Describes primary purpose of the input widget.
This information is useful for on-screen keyboards and similar input methods to decide which keys should be presented to the user.
Note that the purpose is not meant to impose a totally strict rule about allowed characters, and does not replace input validation. It is fine for an on-screen keyboard to let the user override the character set restriction that is expressed by the purpose. The application is expected to validate the entry contents, even if it specified a purpose.
The difference between gtk_input_purpose_digits and gtk_input_purpose_number is that the former accepts only digits while the latter also some punctuation (like commas or points, plus, minus) and “e” or “E” as in 3.14E+000.
This enumeration may be extended in the future; input methods should interpret unknown values as “free form”.