Call a Function from another bas file in FreeBASIC

Question

how do i call a function where it is declared in another bas file? For example i have 2 bas files.

sum.bas

Declare Function sum( As Integer, As Integer ) As Integer

Function sum( a As Integer, b As Integer ) As Integer
Return a + b
End Function

main.bas

Dim a As Integer
a = sum(1, 2)
Print a
Sleep

I set main.bas as the main module but i cannot call sum function....

Answer 1

The solution is the Declare statement to be written in main.bas

sum.bas

Function sum( a As Integer, b As Integer ) As Integer
Return a + b
End Function

main.bas

Declare Function sum( As Integer, As Integer ) As Integer
Dim a As Integer
a = sum(1, 2)
Print a
Sleep

Answer 2

In FreeBASIC like other languages it is possible to separate the code into multiple files, where the main file must include the child files that contain other pieces of code using #include "filename.bas"

sum.bas

Declare Function sum( As Integer, As Integer ) As Integer

Function sum( a As Integer, b As Integer ) As Integer
Return a + b
End Function

main.bas

#include "sum.bas"
'with "INCLUDE" it is as if the code contained in another file was written 
'at that point.

Dim a As Integer
a = sum(1, 2)
Print a
Sleep