[fpc-devel] LoadLibrary fails if called from a DLL
Mark - WBIsoft.COM
mark at wbisoft.com
Sun Jul 8 21:13:57 CEST 2007
Hi Yury,
have now recompiled the DLL with the latest SVN build using the 2_2 fixes but get the same problem, load library returns the same hex value 0x7c37000 - the actual procedure I have in the DLL is as follows
// ------------ cut code here
function GetModuleHandle(lpModuleName: PCHAR): cardinal; stdcall; external 'kernel32.dll' name 'GetModuleHandleA';
function LoadLibrary(lpLibFileName: PCHAR): cardinal; stdcall; external 'kernel32.dll' name 'LoadLibraryA';
function GetProcAddress(hModule: HMODULE; lpProcName: LPCSTR): FARPROC; stdcall; external 'kernel32.dll' name 'GetProcAddress';
procedure debug(fn, tx : string);
var f : textfile;
begin
assignfile(f,'c:\skelgina.log');
if fileexists('c:\skelgina.log') then
append(f)
else
rewrite(f);
writeln (f,timetostr(now) + ' - ' + fn + ': ' + tx);
writeln (f);
closefile(f);
end;
procedure GetProcedureAddress(var P: Pointer; const ModuleName, ProcName: string); stdcall;
var
ModuleHandle: cardinal;
begin
debug('GetProcedureAddress','Called');
debug('GetProcedureAddress','ModuleName: '+modulename);
debug('GetProcedureAddress','ProcName: '+procname);
if not Assigned(P) then
begin
debug('GetProcedureAddress','P is not assigned');
begin
ModuleHandle := SafeLoadLibrary('MSGINA.DLL');
debug('GetProcedureAddress','LoadLibrary MSGINA.DLL returns $'+inttohex(ModuleHandle,16));
end;
P := Pointer(GetProcAddress(ModuleHandle, PChar(ProcName)));
end
else
debug('GetProcedureAddress','P is already assigned');
debug('GetProcedureAddress','Exits - P assigned '+booltostr(assigned(p)));
end;
// ------------ end code here
Any thoughts on this ? I pulled the GetProcedureAddress function from the Jwa??? components to test incase it was my implementation of the LoadLIbrary code in FPC but obviously it's not !!!
Cheers
Mark
----- Original Message -----
From: Yury Sidorov
To: FPC developers' list
Sent: Sunday, July 08, 2007 6:24 PM
Subject: Re: [fpc-devel] LoadLibrary fails if called from a DLL
Go to sources folder and execute:
make distclean
make all
make install SNAPSHOT=1 INSTALL_PREFIX=C:/some_folder
Yury.
----- Original Message -----
From: Mark - WBIsoft.COM
To: FPC developers' list
Sent: Sunday, July 08, 2007 8:15 PM
Subject: Re: [fpc-devel] LoadLibrary fails if called from a DLL
THanks, one final (i hope) question
I assume I need to grab the entire folder and recompile it - if so I assume I can compile with FPC itself ????
Mark
----- Original Message -----
From: Yury Sidorov
To: FPC developers' list
Sent: Sunday, July 08, 2007 6:12 PM
Subject: Re: [fpc-devel] LoadLibrary fails if called from a DLL
Get sources from svn using this path:
http://svn.freepascal.org/svn/fpc/branches/fixes_2_2
I dont know where snapshots can be found.
Yury.
----- Original Message -----
From: Mark - WBIsoft.COM
To: FPC developers' list
Sent: Sunday, July 08, 2007 8:06 PM
Subject: Re: [fpc-devel] LoadLibrary fails if called from a DLL
Thanks,
can you suggest the best way (ie. the correct url) for me to run with the svn.exe command to get the latest snapshot as I'm unsure where the x86_64 stuff is - esp as it would appear to have vanished from the sourceforge page ?
What's the current x86_64 snapshot version ?
Thanks
Mark
----- Original Message -----
From: Yury Sidorov
To: FPC developers' list
Sent: Sunday, July 08, 2007 6:05 PM
Subject: Re: [fpc-devel] LoadLibrary fails if called from a DLL
Hi,
I fixed DLL related a few weeks ago. You need to get more fresh snapshot and test it.
Yury.
----- Original Message -----
From: Mark - WBIsoft.COM
To: FPC developers' list
Sent: Sunday, July 08, 2007 7:59 PM
Subject: Re: [fpc-devel] LoadLibrary fails if called from a DLL
Hi Yury,
specifically the file was lazarus-0.9.23-fpc-2.1.5-20070531-win64.exe
Hope this helps ?
Mark
----- Original Message -----
From: Yury Sidorov
To: FPC developers' list
Sent: Sunday, July 08, 2007 5:28 PM
Subject: Re: [fpc-devel] LoadLibrary fails if called from a DLL
Hello,
How old is snapshot you are using?
Yury Sidorov.
----- Original Message -----
From: Mark - WBIsoft.COM
To: fpc-devel at lists.freepascal.org
Sent: Saturday, July 07, 2007 11:51 AM
Subject: [fpc-devel] LoadLibrary fails if called from a DLL
Hi,
I'm having a strange issue with the LoadLibrary call in the 64bit beta version of the free pascal compiler (fpc 2.1.5 with lazarus 0.9.23 beta) - standard install from the sourceforge download and installed in the default c:\lazarus directory.
I have written a function in FPC that I have used in Delphi for many many years with out problem. Ok, here's a simple piece of code
function myfunction(a, var b : dword) : boolean;
var dllh : cardinal;
fun : function (a : dword; var b : dword) : boolean; stdcall;
begin
result := false;
dllh := loadlibrary('c:\windows\system32\somelib.dll');
if dllh <> 0 then
begin
fun := nil;
fun := getprocaddress(dllh,'someproc');
if fun <> nil then result := fun(a,b);
end
else
result := false;
end;
Now here's my problem - very simply if I compile this into a standard console application it works fine, however, if I compile it into the DLL I am planing to run it in it fails - the loadlibrary call ALWAYS returns 0x7C370000 which appears to be a memory address rather than a handle - the result is that the getprocaddress returns an invalid address and fails.
So, why is the loadlibrary call failing (or returning this memory address) when in a DLL but NOT when it's in a console app.
Any help would be great, as I cannot seem to find an implementation of GETLASTERROR to pass to SYSERRORMESSAGE to display any error from the OS if there is one !
Thanks folks
Mark
Kind regards
Mark Cook
WBIsoft.COM
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