(), UI_dup_verify_string(), UI_add_input_boolean(), UI_dup_input_boolean(), UI_add_info_string(), UI_dup_info_string(), UI_add_error_string() and UI_dup_error_string() return a positive number on success or a value which is less than or equal to 0 otherwise.</p>

<p>UI_construct_prompt() returns a string or NULL if an error occurred.</p>

<p>UI_dup_user_data() returns 0 on success or -1 on error.</p>

<p>UI_get0_result() returns a string or NULL on error.</p>

<p>UI_get_result_length() returns a positive in