Check Input hook

Use this hook to validate a field. You can use and set the values of the form fields. You can only use this hook to set additional restrictions on a field. The standard validations are also applied.

Example:

function extern void currency.check.input()
{
        if txcomdll0001.is.currency.blocked.for.printing(currency) then
                set.input.error("@" & 
                    sprintf$("You cannot select currency %s; it is blocked",
                            currency))
        endif
}