read_input and function clause error

[Dmitrii Dimandt]

I battled unsuccesfully with read_input and then decided to give read_input_string a try. Same problem

read_input is defined in ewgi_api as

read_input(Callback, Length, Ctx) when ?IS_EWGI_CONTEXT(Ctx),
is_function(Callback, 1),
is_integer(Length),
Length >= 0 ->
case read_input(Ctx) of
F when is_function(F, 2) ->
F(Callback, Length);
undefined ->
undefined
end.

When a callback is defined, F is called with F(Callback, Length). This is where the process hangs for a while and then fails with

=ERROR REPORT=
function_clause

I haven't been able to find out why this happens, but it does. I'll try to investigate a bit further tonight.