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what is wring with code get IP & TCP Installed installation

Posted on 2010-08-13
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Last Modified: 2012-05-10
I#m using these little function to get IP Number and information if TCP is avail. since a long time.

It has been OK since 5 years and inside a test application it also works fine, but in the target application i'm calling that 2 function a get a access violation inside ws2_32.dll  while doing a gethostname call

why ?

do not net any other solution code  eg. with INDY ......
function GetIPAddress: string;
var    phoste  : PHostEnt;
       Buffer  : PAnsiChar;
       WSAData : TWSADATA;
begin
  // result := '';
  if WSAStartup($0101, WSAData) <> 0 then exit;
  GetHostName(Buffer, SizeOf(Buffer));
  phoste :=GetHostByName(buffer);
  if phoste = nil then result := '127.0.0.1' else
  result := StrPas(inet_ntoa(PInAddr(phoste^.h_addr_list^)^));
  WSACleanup;
end;



function IsTCPIP: boolean;
var wsaData: TWSAData;
begin
   result := true;
   case Winsock.WSAStartup($0101, wsaData) of
    WSAEINVAL, WSASYSNOTREADY, WSAVERNOTSUPPORTED: result := false;
   else
    Winsock.WSACleanup
   end;
end;

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Question by:BdLm
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6 Comments
 
LVL 14

Expert Comment

by:systan
ID: 33435634
.
function GetIPAddress: string;
var    phoste  : PHostEnt;
       Buffer  : PAnsiChar;
       WSAData : TWSADATA;
begin
  result := '127.0.0.1';
  if WSAStartup($0101, WSAData) <> 0 then exit;
  GetHostName(Buffer, SizeOf(Buffer));
  phoste :=GetHostByName(buffer);
  if phoste = nil then result := '127.0.0.1' else
  result := StrPas(inet_ntoa(PInAddr(phoste^.h_addr_list^)^));
  WSACleanup;
end;



function IsTCPIP: boolean;
var wsaData: TWSAData;
begin
   case Winsock.WSAStartup($0101, wsaData) of
   WSAEINVAL, WSASYSNOTREADY, WSAVERNOTSUPPORTED:
   result := false;
   else
   result := true;
   end;
   Winsock.WSACleanup
end;

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LVL 8

Author Comment

by:BdLm
ID: 33435637
can you understand the errpor mechanism ? 

must a PAnsichar always have a value assigend before calling  function hostname ? 

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LVL 37

Expert Comment

by:Geert Gruwez
ID: 33436313
solution with indy is very easy:


var
  IdIPWatch1: TIdIPWatch;

  IdIPWatch1.Active := True;
  ShowMessage(IdIPWatch1.CurrentIP);
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LVL 8

Author Comment

by:BdLm
ID: 33439716
the AV is gone with the new line of code , but still the buffer seem to be nil, a working reference code I found at the net, pretty similiar but working compared to mine.

Can't get a idea why this code works but my code doee not ....  


function GetIPFromHost
(var HostName, IPaddr, WSAErr: string): Boolean; 
type 
  Name = array[0..100] of Char; 
  PName = ^Name; 
var 
  HEnt: pHostEnt; 
  HName: PName; 
  WSAData: TWSAData; 
  i: Integer; 
begin 
  Result := False;     
  if WSAStartup($0101, WSAData) <> 0 then begin 
    WSAErr := 'Winsock is not responding."'; 
    Exit; 
  end; 
  IPaddr := ''; 
  New(HName); 
  if GetHostName(HName^, SizeOf(Name)) = 0 then
  begin 
    HostName := StrPas(HName^); 
    HEnt := GetHostByName(HName^); 
    for i := 0 to HEnt^.h_length - 1 do 
     IPaddr :=
      Concat(IPaddr,
      IntToStr(Ord(HEnt^.h_addr_list^[i])) + '.'); 
    SetLength(IPaddr, Length(IPaddr) - 1); 
    Result := True; 
  end
  else begin 
   case WSAGetLastError of
    WSANOTINITIALISED:WSAErr:='WSANotInitialised'; 
    WSAENETDOWN      :WSAErr:='WSAENetDown'; 
    WSAEINPROGRESS   :WSAErr:='WSAEInProgress'; 
   end; 
  end; 
  Dispose(HName); 
  WSACleanup;
end;

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LVL 14

Accepted Solution

by:
systan earned 500 total points
ID: 33440152
Are you trying to get your own ip address? or from any host?
Here is the code if you want it;
Just create a new form with
  Label1: TLabel;
  Edit1: TEdit;
  Button1: TButton;

  ListBox1: TListBox;
  ListBox2: TListBox;
  Label2: TLabel;

Double click the form, double click the button, erase all the default codes inside, then copy and paste the code below.

unit Unit1;

interface

uses winsock,
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)

    Label1: TLabel;
    Edit1: TEdit;
    Button1: TButton;

    ListBox1: TListBox;
    ListBox2: TListBox;
    Label2: TLabel;

    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure ListBox1DblClick(Sender: TObject);

  private
    { Private declarations }
    function NetCheck(const networkfoldertosave:string): boolean;
    procedure netSave(const netcpufoldername:string);

  public
    { Public declarations }

  end;

var
  Form1: TForm1;

implementation
 uses ShellApi;
{$R *.dfm}

function GetRemoteIPAddress(ComputerName : string) : string;
var
  wsdata : TWSAData;
  he : PHostEnt;
  ss : pchar;
  ip : TInAddr;
begin
  WSAStartup(MakeWord(1, 1), wsdata);
  he := gethostbyname(pchar(ComputerName));
  if he<>nil then begin
    ip.S_addr := integer(pointer(he^. h_addr_list^)^);
    ss := inet_ntoa(ip);
    Result := string(ss);
  end;
  WSACleanup();
end;

procedure EnumRemoteDrives(Items: TStringlist);
function EnumerateFunc(lpnr: PNetResource; Items: TStringList; DrillDepth: Integer): Boolean;
var
lpnrLocal: PNetResource;
hEnum:THandle;
dwResult, dwResultEnum, cbBuffer, cEntries: DWORD;
i: Integer;
p1:PChar;
p2:PnetResource;
s, t: string;
begin
dwResult := WNetOpenEnum(RESOURCE_GLOBALNET,RESOURCETYPE_DISK, 0, lpnr, hEnum);
if dwResult <> NO_ERROR then begin EnumerateFunc := False;
exit;
end;
cbBuffer := 32768;
cEntries := $FFFFFFFF;
lpnrLocal := PNetResource(GlobalAlloc(GPTR,cbBuffer));
repeat
dwResultEnum := WNetEnumResource(hEnum,cEntries, lpnrLocal, cbBuffer);
if dwResultEnum = NO_ERROR then begin
for i := 0 to cEntries - 1 do begin
p1 := PChar(lpnrLocal) + i *
SizeOf(TNetResource);
p2 := PNetResource(p1);
s := StrPas(p2^.lpRemoteName);
if Length(s) > 2 then
if (s[1] = '\') and
(s[2] = '\') then begin
t := Copy(s,
3, Length(s) - 2);
if Pos('\', t)
<> 0 then
items.Add(s);
end;
if (p2.dwUsage and RESOURCEUSAGE_CONTAINER) = RESOURCEUSAGE_CONTAINER then
if DrillDepth < 3 then
EnumerateFunc(p2, Items, DrillDepth + 1);
end;
end;
until dwResultEnum = ERROR_NO_MORE_ITEMS;
GlobalFree(HGLOBAL(lpnrLocal));
dwResult := WNetCloseEnum(hEnum);
if dwResult <> NO_ERROR then begin EnumerateFunc := False;
 exit;
  end;
EnumerateFunc := True;
end;
begin
EnumerateFunc(nil, Items, 0);
end;

function Tform1.NetCheck(const networkfoldertosave:string): boolean;
var
netx: string;
i: byte;
sl,nx : tstringlist;
p,q:integer;
begin
result:=false;
sl := tstringlist.create;
nx := tstringlist.create;
nx.Duplicates := dupIgnore;

EnumRemoteDrives(sl);
for i:= 0 to sl.Count-1 do
begin
netx:=sl[i];
listbox1.items.add(netx);
if uppercase(netx) = uppercase(networkfoldertosave) then result:=true;

q:=0;
p:=0;
repeat
inc(q);
p:=AnsiPos('\',netx);
netx:=copy(netx,p+1,length(netx));
until q=2;
p:=AnsiPos('\',netx);
delete(netx,p,length(netx));
if nx.IndexOf(netx)= -1 then nx.Add(netx);
end;

for q:= 0 to nx.Count-1 do listbox2.items.add(nx[q] + ' is ' +  GetRemoteIPAddress(nx[q]) );
sl.free;
nx.Free;
end;


procedure TForm1.netSave(const netcpufoldername:string);
begin
if netCheck(netcpufoldername) = true then
begin
//add your code the way you want it here
showmessage(netcpufoldername + ' is Active and ready to save files,  copying files now........');
end
else
begin
showmessage(netcpufoldername + ' is NOT Active and NOT ready to save files');
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
Form1.Caption := 'WorkGroup Computers';
Label1.Caption := 'Find Sample:  \\COMPUTERNAME\FOLDERNAME';
Label2.Caption := 'Double click to open shared network';
Button1.Caption := 'Viewit';
Button1.Hint := 'Just hit me';
Edit1.Text := 'anyshared';
end;


procedure TForm1.Button1Click(Sender: TObject);
begin
Listbox1.Clear;
Listbox2.Clear;
netSave(Edit1.text);
//close;
end;


procedure TForm1.ListBox1DblClick(Sender: TObject);
begin
ShellExecute(Handle,'open', Pchar(listbox1.items[listbox1.itemINdex]), nil, nil, SW_SHOWNORMAL) ;
end;


end.

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LVL 8

Expert Comment

by:GeneralTackett
ID: 33468559
other solution could be that you are referencing an old dll.. you could include this old dll in your program directory which would be searched first and all would be well as you have used it for years..  
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