Sets the contents of the selection from a UTF-8 encoded string. The string is converted to the form determined by @selection_data->target.
a UTF-8 string
the length of @str, or -1 if @str is nul-terminated.
%TRUE if the selection was successfully set, otherwise %FALSE.
See Implementation
Sets the contents of the selection from a UTF-8 encoded string. The string is converted to the form determined by @selection_data->target.