pointerp() - identifies whether a given variable is an array
int pointerp( mixed arg );
Returns 1 if 'arg' is an array, otherwise returns 0.
int is_array = pointerp( ({ 1, 2, 3, 4 }) ); // 1
int is_array = pointerp( "Foo" ); // 0
mapp(3), stringp(3), objectp(3), intp(3), bufferp(3), floatp(3), func‐
tionp(3), nullp(3), undefinedp(3), errorp(3), arrayp(3)