Mega Code Archive
Determine your local ip
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Another piece of code to determine your machine's local IP number -
the function GetLocalIP returns it as a string.
Note:
If you run through NAT (network address translation) then your public address can only be told by someone else like:
http://www.myip.dk/
function LWToIP(LW: LongWord): string;
begin
Result := IntToStr(LW and $FF);
LW := LW shr 8;
Result := Result + '.' + IntToStr(LW and $FF);
LW := LW shr 8;
Result := Result + '.' + IntToStr(LW and $FF);
LW := LW shr 8;
Result := Result + '.' + IntToStr(LW and $FF);
end;
function TForm1.GetLocalIP: string;
var
name, A: PChar;
h: hostent;
I: Integer;
begin
GetMem(name,255);
try
I := GetHostName(name,255);
if I <> 0 then
I := wsagetlastError;
if I <> 0 then
StatusBar1.Panels[0].Text := 'Error: ' + IntToStr(I)
else
begin
h := GetHostByName(name)^;
if h.h_length <> 4 then Result := ''
else
begin
A := h.h_addr_list^;
I := 0;
while (A^ <> #0) and (CompareStr(A,h.h_name) <> 0) do
begin
inc(I,4);
Inc(A,4)
end;
if I < 4 then
begin
Result := h.h_name
end
else
begin
while I >= 4 do
begin
Dec(A,4);
Dec(I,4);
Result := Result + LWToIP(PLongWord(A)^) + ', ';
end;
Delete(Result,Length(Result)-1,2);
end
end
end
finally
FreeMem(name)
end
end;
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