Gcc extension: have a semicolon after a function definition ??

["Michael Gong" <mwgong@xxxxxxxxxxxxxx>]

Hi,

I am wondering why following program is compiled successfully by gcc ? 
Please notice there is a ";" after the function definition.

Is there a gcc extension for it ?

/* foo.c */
int main() {
   printf("hello world\n");
} ;

Thanks.

Michael