Passing Arguments to Procedure (WMI, FSWbemLocator.ConnectServer,
0x800706BA)
lazarus / 34-Windows

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devers000 · 2017-03-13 20:41

Hi All!
I'm trying to write application to automate remote information
gathering.
I use Lazarus v. 1.6.4 (fpc 3.0.2) and wmi-delphi-code-creator v.
1.9.9.350
Here is the code:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
GetWMI_Info; {$mode objfpc} {$H+} uses  SysUtils,  ActiveX,  ComObj, 
Variants;                procedure
 GetWin32_BaseBoardInfo(WbemComputer, WbemUser, WbemPassword:
string);const  wbemFlagForwardOnly = $00000020;var  FSWbemLocator :
OLEVariant;  FWMIService   : OLEVariant;  FWbemObjectSet: OLEVariant; 
FWbemObject   : OLEVariant;  oEnum         : IEnumvariant;  sValue   
   : string;  i             : LongWord;   begin;  i := 0; 
FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator'); 
FWMIService   := FSWbemLocator.ConnectServer(WbemComputer,
'root\CIMV2', WbemUser, WbemPassword);  FWbemObjectSet:=
FWMIService.ExecQuery('SELECT * FROM
Win32_BaseBoard','WQL',wbemFlagForwardOnly);  oEnum         :=
IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;  while
oEnum.Next(1, FWbemObject, i) = 0 do  begin    sValue:=
FWbemObject.Properties_.Item('Manufacturer').Value;   
Writeln(Format('Manufacturer    %s',[sValue]));   
FWbemObject:=Unassigned;  end;end; begin try   
GetWin32_BaseBoardInfo('PCNAME','user','password'); except    on
E:EOleException do        Writeln(Format('EOleException %s %x',
[E.Message,E.ErrorCode]));              on E:Exception do       
Writeln(E.Classname, ':', E.Message); end; Writeln('Press Enter to
exit'); Readln;    end.
When I run application using this code I have the following error:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
EOleException RPC server is unavailable.  800706BA
But if I change code like this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i FWMIService
  := FSWbemLocator.ConnectServer('PCNAME', 'root\CIMV2', 'user',
'password');Application works without error...
I think that passing arguments to procedure is wrong but I don't
understand why...
Please, help to solve this problem. Any help is appreciated! Thanks

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Thaddy · 2017-03-13 20:45

Try Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
 GetWin32_BaseBoardInfo(WbemComputer, WbemUser, WbemPassword:
widestring);WMI is a widestring API, so pass it widestring or
unicodestring - which is a refcounted 16bit widestring -. sValue
should also be widestring or unicodestring.

I see you have a console program. In that case you can change the mode
to {$MODE DELPHIUNICODE} instead of objfpc. Then all strings are 16bit
unicode by default.
Don't do this is in a Lazarus GUI app. There you should specify the
strings as widestring or unicode string when calling a 16bit string
API like WMI.

So my guess is that your console program works if you change it just a
little:Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
GetWMI_Info; {$mode delphiunicode} {$H+}
wmi-delphi-code-creator is broken for current Lazarus versions because
of the "enlightened" UTF8 string type.
Until Lazarus (and fpc rtl) supports UTF16 fully, you should specify a
16bit string type when doing
Windows API calls, or use mode delphiunicode for console apps like
your example.

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devers000 · 2017-03-14 21:03

Thank you, Thaddy! 
I develop GUI and you're right! I need to use WideString.
Now it's working like a charm!

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JuhaManninen · 2017-03-14 21:41

Quote from: devers000 on March 14, 2017, 10:03:02 pmThank you,
Thaddy! 
I develop GUI and you're right! I need to use WideString.
Actually you should use UnicodeString instead.
A nice bonus with the Lazarus UTF-8 system is that your code is
compatible with Delphi at source level when using UnicodeString for
the API calls despite the encoding differences.
Another thing to remember: you must assign string constants only to
type "string" variables which is also Delphi compatible.