Hi everyone.
I have to work with old utility: which converts xls into txt.
There was a small problem in logic of the utility, but the problem is in other thing...
The utility consists of two parts: exe module and dll module, and uses MFC.
In exe project we have
pInit = (t_bXR_Init)GetProcAddress(hExcel, _T("bXR_Init"));
and
pInit("logfiles",false);
In dll project we have
typedef bool (*t_bXR_Init) (CString const &strlogfilespath, bool btxtfile);
XLSREADER_API bool bXR_Init(CString const &strlogfilespath, bool btxtfile);
The problem is when we send argument "logfiles" into the function it doesn't get it. It's strange, 'cause all other parameters are send properly.
The reason is somehow connected with using of CString. But I don't know how...
XLSREADER_API is defined as:
#define XLSREADER_API extern "C" __declspec(dllimport)
Also I've added
AFX_MANAGE_STATE(AfxGetStaticModuleState());
in the beginning of function's body (for bXR_Init). But it didn't help.
Also I tried to change some settings for these two projects, all settings are the same (e.g. calling conversion is __cldecl(/Gd); I build either debug versions exe and dll or release version of exe and dll simultaneously).
Also I tried to use CString instead of CString& - the same situation. It works properly if use char*, but boss says to find what the origin of the problem is at first.
What may lead to the problem (the function doesn't get CString parameter)?
To pass a complex type such as a CString across a DLL boundary you have to make sure that both the DLL and the exe are using the exact same DLL libraries. Set "Runtime Library" to multi-threaded DLL and set "Use of MFC" to Use MFC in a Shared DLL. Also, don't mix debug and release modules: Both must be the same.
Without these conditions you get two different heaps, and you can't keep the allocations/deletions compatible with two heaps.
Try passing an actual CString parameter to the call:
CString sPath = "logfiles";
pInit(sPath,false);
wtfigo! (what the f is going on)
the problem is solved.
I discovered, that exe project had "character set" = "use multibyte character set"
and dll project had "character set" = "use unicode character set".
So, dll function got CString with char* inside, but considered it as CString with wchat_t* inside. And it looked as garbage (as complete garbage on my pc and as chinese symbols on my workmate's pc).
I changed "character set" for exe project to "use unicode character set" and discovered about 60 errors.
Then I read an article http://habrahabr.ru/post/164193/ (in russian; or in english: http://www.codeproject.com/Articles/76252/What-are-TCHAR-WCHAR-LPSTR-LPWSTR-LPCTSTR-etc).
And fixed all errors, widely used macroses from TCHAR.h (MSDN helped me).
Thanks everybody for your help.
Related
So I'm writing a standalone JScript file to be executed by Windows Script Host (this file is not going to be used as a web application).
My goal is to load a dll file. Just like using LoadLibrary function in a C++ application.
I tried researching the subject but I didn't come up with anything useful. I'm so lost I don't have any piece of code to share. I understand using ActiveXObject may come to my rescue. if so, any idea how to use it?
Update:
If we all agree that loading is impossible, I'll settle for validity check. Meaning, don't try to load but check if it is loaded and functional.
You can export a specific function for this purpose.
Then, from your JScript, execute rundll32.exe and check that the function ran as expected.
You might also give Gilles Laurent's DynaWrap
ocx a chance.
This kind of dll needs to be registered on the target system like regsvr32 /s DynaWrap.dll.
It is restricted to 32-bit DLLs, and this might be inconvenient for you to use, but it works on a 64bit Windows. You can't access function exported by ordinal number and you can't directly handle 64bit or greater values/pointers.
Here's a sample to call MessageBoxA from JScript:
var oDynaWrap = new ActiveXObject( "DynamicWrapper" )
// to call MessageBoxA(), first register the API function
oDynaWrap.Register( "USER32.DLL", "MessageBoxA", "I=HsSu", "f=s", "R=l" )
// now call the function
oDynaWrap.MessageBoxA( null, "MessageBoxA()", "A messagebox from JScript...", 3 )
And here from VBScript:
Option Explicit
Dim oDynaWrap
Set oDynaWrap = CreateObject( "DynamicWrapper" )
' to call MessageBoxA(), first register the API function
UserWrap.Register "USER32.DLL", "MessageBoxA", "I=HsSu", "f=s", "R=l"
' now call the function
UserWrap.MessageBoxA Null, "MessageBoxA()", "A messagebox from VBScript...", 3
To use a function you need to "register" the exported function of your DLL.
To do this you need to call the register method with a first parameter containing a string object to the complete path of the DLL, a second parameter for the exported name of the function to use, and following three paremeters describing the functions declartion in a somehow obscure syntax.
i= describes the number and data type of the functions parameters.
f= describes the type of call: _stdcall or _cdecl. Default to _stdcall.
r= describes the return values data type.
The supported data types are:
Code Variant Description
a VT_DISPATCH IDispatch*
b VT_BOOL BOOL
c VT_I4 unsigned char
d VT_R8 8 byte real
f VT_R4 4 byte real
h VT_I4 HANDLE
k VT_UNKNOWN IUnknown*
l VT_I4 LONG
p VT_PTR pointer
r VT_LPSTR string by reference
s VT_LPSTR string
t VT_I2 SHORT
u VT_UINT UINT
w VT_LPWSTR wide string
Thus the Register method call used in the examples describes MessageBoxA like this:
_stdcall LONG MessageBoxA( HANDLE, LPSTR, LPSTR, UINT );
For a explanation of MessageBoxA look at the docs on MSDN.
Please read the DynaWrap docs for more sophisticated examples... But you might need Google translate, 'cos they are written in french ;-)
To be able to use a dll as ActiveXObject, it needs to be registered as COM object. There are some restrictions on this but if you have a code for this dll, it is certainly doable.
When you register your dll as COM object, it is assigned a name. You use this name to create an object. This example from MSDN uses excel since it is already registered if you installed office.
var ExcelApp = new ActiveXObject("Excel.Application");
var ExcelSheet = new ActiveXObject("Excel.Sheet");
// Make Excel visible through the Application object.
ExcelSheet.Application.Visible = true;
// Place some text in the first cell of the sheet.
ExcelSheet.ActiveSheet.Cells(1,1).Value = "This is column A, row 1";
// Save the sheet.
ExcelSheet.SaveAs("C:\\TEST.XLS");
// Close Excel with the Quit method on the Application object.
ExcelSheet.Application.Quit();
Apart from restriction of registering dll, using dll is no different from using it as c++ or c# dll. Note that, C# (or other .NET dlls) should be ComVisible to be used from javascript this way.
EDIT: The only other way of using C/C++ dll from javascript is swig interfaces. I have not used it, therefore I can only point you in that direction.
SWIG is a software development tool that connects programs written in
C and C++ with a variety of high-level programming languages. SWIG is
used with different types of target languages including common
scripting languages such as Javascript, Perl, PHP, Python, Tcl and
Ruby.
I have an existing project, originally implemented as a Vxworks 5.5 style kernel module.
This project creates many tasks that act as a "host" to run external code. We do something like this:
void loadAndRun(char* file, char* function)
{
//load the module
int fd = open (file, O_RDONLY,0644);
loadModule(fdx, LOAD_ALL_SYMBOLS);
SYM_TYPE type;
FUNCPTR func;
symFindByName(sysSymTbl, &function , (char**) &func, &type);
while (true)
{
func();
}
}
This all works a dream, however, the functions that get called are non-reentrant, with global data all over the place etc. We have a new requirement to be able to run multiple instances of these external modules, and my obvious first thought is to use vxworks RTP to provide memory isolation.
However, no matter what I try, I cannot persuade my new RTP project to compile and link.
error: 'sysSymTbl' undeclared (first use in this function)
If I add the correct include:
#include <sysSymTbl.h>
I get:
error: sysSymTbl.h: No such file or directory
and if i just define it extern:
extern SYMTAB_ID sysSymTbl;
i get:
error: undefined reference to `sysSymTbl'
I havent even begun to start trying to stitch in the actual module load code, at the moment I just want to get the symbol lookup working.
So, is the system symbol table accessible from VxWorks RTP applications? Can moduleLoad be used?
EDIT
It appears that what I am trying to do is covered by the Application Programmers Guide in the section on Plugins (section 4.9 for V6.8) (thanks #nos), which is to use dlopen() etc. Like this:
void * hdl= dlopen("pathname",RTLD_NOW);
FUNCPTR func = dlsym(hdl,"FunctionName");
func();
However, i still end up in linker-hell, even when i specify -Xbind-lazy -non-static to the compiler.
undefined reference to `_rtld_dlopen'
undefined reference to `_rtld_dlsym'
The problem here was that the documentation says to specify -Xbind-lazy and -non-static as compiler options. However, these should actually be added to the linker options.
libc.so.1 for the appropriate build target is then required on the target to satisfy the run-time link requirements.
In my MFC ActiveX program, there is a calling of function offered by a dll file. And there is a struct type parameter in the function. The strange thing I met is after calling the function, the data in struct is not complete. I am a newer of ActiveX and DLL, and really can't understand how can this happened... The main codes are below:
The defination of struct:
typedef struct{
WORD m_protocol;
WORD m_playstart;
...
char url[128];
char username[MAX_USER_NAME_LEN+1];
char password[MAX_PASSWORD_LEN+1];
}CHANNEL_CLIENTINFO;
The ActiveX codes:
CHANNEL_CLIENTINFO channelInfo;
...
...
GSNET_ClientStart(&channelInfo);
The dll codes:
GSNET_ClientStart(CHANNEL_CLIENTINFO *m_pChaninfo)
{
...
...
}
Can anyone help me? Thanks all.
for more details:
In ActiveX program, before call the GSNET_ClientStart, I initialize the struct with some date. Such as the 'url':
sprintf(channelInfo.url, "192.168.121.122");
And after the calling, in dll function GSNET_ClientStart, I get out the url, it turns out to be "168.121.122", the "192." is missing.
I can make sure that I did't make any mistake in basic grammar.
There is a layout mismatch between the struct definitions in your two modules. It seems that the offset to the url member in your DLL has an offset of 4 more than the offset to that field in your ActiveX.
Make sure that the struct definitions match in both modules. Make sure that the compiler options relating to struct layout are the same in both modules.
I cannot give a definitive fix because there are so many ways in which this mismatch could occur, but for sure the root problem is a mismatch.
This is at least a documentation error, if not a bug.
In VB.NET prior to .NET 4.0 (i.e. VB.NET 7 through 9) an empty Structure declaration fails at compile-time with
error BC30281: Structure 'MySimpleEmpty' must contain at least one instance member variable or Event declaration.
E.g. The following two structures compile successfully in VB10, and not prior:
Structure MySimpleEmpty
End Structure
Public Structure AnotherEmpty
Public Const StillEmpty As Boolean = True
End Structure
I note the documentation for the Error BC30281 stops at VB9, but the documentation for the Structure statement still has the datamemberdeclarations as required even as of VB11 (.NET 4.5 VS2012).
These two Structures compile in VB11 (VS2012) as well. (Thanks John Woo.)
Is there some blog entry or documentation confirming this is an intended change or a bug in VB10 and later?
Microsoft have marked this as a fixed bug, without actually stating what was fixed.
The VB11 (VS2012) documentation now says the datamemberdeclarations are optional in the grammar, but in the Parts table it says "Required. Zero or more..."!
I guess that's a fix... The VB10 (VS2010) documentation hasn't been changed.
I'm trying get the address of GetProcAddress with GetProcAddress (yes. calling it on itself).
When I'm doing it from an empty exe project I get a valid address (between the allocated address of kernel32).
When I'm calling it from a dll, I'm getting invalid address (not in the range of the allocated kernel32)
What is the difference?
I'm running on windows 7 with 64 bit.
The project are compiled as 32 bit.
Here is the code that I'm running:
typedef FARPROC (WINAPI * GetProcAddressType)(HMODULE , LPCSTR );
HMODULE kernel32Hmodule = LoadLibraryW(L"c:\windows\system32\kernel32.dll");
GetProcAddressType abc = (GetProcAddressType)GetProcAddress(kernel32Hmodule, "GetProcAddress");
I also tried to get the address like this: void* a = GetProcAddress;
but it returns the same invalid address when running from a dll...
Please help.
Exe are normally loaded at their preferred addresses, DLL are often relocated (not loaded at their preferred addresses) when they opt for ASLR and when the relocation is needed (e.g. their preferred address is already taken). This could explain the delta you experienced between the behaviours.
ok i found the problem. when i loaded the dll with rundll32 it acted wierd... when i build a loader by myself (loadlibrary, than getprocaddress) it worked fine. rundll32 is the one caused the problems