Is an exception specification needed if the method throws and catchesits own exception?

[elcapitan666]

Is an exception specification need if the method itself throws and
catches its own exception? ie

void foo( ) throw( runtime_error )
{
fstream infile;

try
{
infile.open( "myfile.txt" );

if( !infile )
throw runtime_error( "Error opening file" );
}

catch( runtime_error & err )
{ cout << err.what( ) << endl; }
}

[elcapitan666]

Thank you Alf, much appreciated.