gstream-set_max_input_length (3) - Linux Man Pages
DESCRIPTIONThis sets the maximum number of characters that the inputter will accept from the user at the next, and only the next, input, i.e. if you call this function with 5
abcde|he won't be able to enter anymore characters before at least one of them has been deleted. If the three middle characters are deleted
a|ethen it is possible to enter three new characters wherever the user want. For example
1a2e3|Note that it is possible to set a default string which is longer than this supplied value; in that case the user will have to delete some characters if he wants to enter any himself.
Also note that this function only affects the next input, not the inputs after that.