[Swig-user] Error in while building Perl module

[velusamy v. <vel...@gm...>]

Dear All,
   When I execute the given example in the Introduction part, I have
received the following error
swig -perl example.i
example.i:7: Error: Syntax error in input(1).
*** No module name specified using %module or -module.

my example.c
double  My_variable  = 3.0;

/* Compute factorial of n */
int  fact(int n) {
        if (n <= 1) return 1;
        else return n*fact(n-1);
}

/* Compute n mod m */
int my_mod(int n, int m) {
        return(n % m);
}

my example.i file

module example
%{
/* Put headers and other declarations here */
extern double My_variable;
extern int    fact(int);
extern int    my_mod(int n, int m);
%}

extern double My_variable;
extern int    fact(int);
extern int    my_mod(int n, int m);


What is the problem, please any one help me......

Regards,
Velusamy.