The input signal can be used to influence the conversion of the users input into a double value.
The signal handler is expected to use get_text to retrieve the text of the entry
and set new_value to the new value.
The default conversion uses g_strtod.
| new_value |
return location for the new value |
|
true for a successful conversion, false if the input was not handled, and gtk_input_error if the conversion failed. |