怎么处理异常？(50分)

function GetIPFromName(Name: string): string;
var
WSAData: TWSAData;
HostEnt: PHostEnt;
begin
WSAStartup(2, WSAData);
HostEnt := gethostbyname(PChar(Name));
with HostEnt^ do
** Result := Format('%d.%d.%d.%d', [Byte(h_addr^[0]),Byte(h_addr^[1]), Byte(h_addr^[2]), Byte(h_addr^[3])]);
WSACleanup;
end;
end;


这个过程是通过局域网中的计算机名来找计算机IP地址的。
当给出的计算机名并不存在的时候"**"行就会出错。
我怎样做才能让出错时，Result为"invalid" ?
try finally 怎么用？ 谢谢

function GetIPFromName(Name: string): string;
var
WSAData: TWSAData;
HostEnt: PHostEnt;
begin
try
WSAStartup(2, WSAData);
HostEnt := gethostbyname(PChar(Name));
with HostEnt^ do
Result := Format('%d.%d.%d.%d', [Byte(h_addr^[0]),Byte(h_addr^[1]), Byte(h_addr^[2]), Byte(h_addr^[3])]);
WSACleanup;
end;
except
Result:='Invalid';
end;
end;

function GetIPFromName(Name: string): string;
var
WSAData: TWSAData;
HostEnt: PHostEnt;
begin
try
WSAStartup(2, WSAData);
try
HostEnt := gethostbyname(PChar(Name));
with HostEnt^ do
Result := Format('%d.%d.%d.%d', [Byte(h_addr^[0]),Byte(h_addr^[1]), Byte(h_addr^[2]), Byte(h_addr^[3])]);
finally
WSACleanup;
end;
end;
except
Result:='Invalid Computer Name';
end;
end;

thanx