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call a managed COM object from an unmanaged c++ SamDav18-May-04 0:14 SamDav 18-May-04 0:14  Hello, I’m trying to call a managed COM object from an unmanaged c++ program. I get this one link error. Any ideas? Compiling... asam.cpp Linking... Creating library Debug/MyCPrj.lib and object Debug/MyCPrj.exp asam.obj : error LNK2019: unresolved external symbol "void __stdcall _com_issue_errorex(long,struct IUnknown *,struct _GUID const &)" (?_com_issue_errorex@@YGXJPAUIUnknown@@ABU_GUID@@@Z) referenced in function "public: long __thiscall IClassfincom::print(void)" (?print@IClassfincom@@QAEJXZ) Debug/MyCPrj.dll : fatal error LNK1120: 1 unresolved externals The same c++ program, works well in a standalone c++ project. The listing: #include "stdafx.h" #include "asam.h" #pragma warning (disable: 4278) #import <mscorlib.tlb> raw_interfaces_only #import "D:\Documents and Settings\Sam\My Documents\Visual Studio Projects\finalCOM\finalCOM\bin\Debug\finalCOM.tlb" no_namespace named_guids extern void sammain(void) { IClassfincom *cpi = NULL; // Initialize COM and create an instance of the InterfaceImplementation class: CoInitialize(NULL); HRESULT hr = CoCreateInstance(CLSID_Classfincom, NULL, CLSCTX_INPROC_SERVER, IID_IClassfincom, reinterpret_cast<void**>(&cpi)); if (FAILED(hr)) { printf("Couldn't create the instance!... 0x%x\n", hr); } else { cpi->print(); cpi->Release(); cpi = NULL; } // Be a good citizen and clean up COM: CoUninitialize(); } i cannot register activeX control on registry. ekklesia14-May-04 20:01 ekklesia 14-May-04 20:01  Hi! my name is jinsoo. i am korean after installing xp service pack 1 and latest windows update. i cannot register activeX control on registry. when in 2003. this job was good in windows 2000. so though using regsvr32.exe not vc++ tool .the result was the same. the error message is 0x80070715. though i find the error message in msdn. i can not find that. my system is windows xp. tool is VC++(Serviced pack 6.0). i hope you help me to solve this problem. nice to meet u nice to meet u Re: i cannot register activeX control on registry. Andrew Quinn AUS17-May-04 5:48 Andrew Quinn AUS 17-May-04 5:48  Hi Jinsoo, Can you give more information? Is this your ActiveX object? Is it MFC/ATL ?? When I have issues like this then try debugging the registration of the control, for an ATL example: Put a breakpoint in your DllRegisterServer function. - Goto Project/Settings Menu in Visual Studio - Click the Debug tab on the right-hand side. - Type in "C:\WINDOWS\system32\regsvr32.exe" into the "Executable for debug session" text box - Put the full path of the debug binary into the "Program Arguments" text box Now run the debugger, you will get a dialog box asking if you want to continue (it is just informing you that regsvr32.exe you are running has no debug info.) Click OK and you should soon be put into the DllRegisterServer function, now just drill down until you come across the error. Cheers, Andy QueryInterface() skruss14-May-04 13:40 skruss 14-May-04 13:40  Hi, Could anybody explain why in QueryInterface()we use static_cast for casting pointers to interfaces to be returned by the functions, but inside the function in order to call AddRef() we call reintepret_cast like this: reinterpret_cast<iunknown*>(*ppv)->AddRef();? Why not just using static_cast as well? Any input would be of great value and much appreciated. Thanks. skruss Re: QueryInterface() ekklesia15-May-04 5:44 ekklesia 15-May-04 5:44  if you find these words like static_cast,reintepret_cast and dynamic_cast on msdn you will find the answer. nice to meet u Re: QueryInterface() skruss25-May-04 11:59 skruss 25-May-04 11:59  Thanks very much. I looked their and found it very helpful indeed. Nice to meet you too. skruss Re: QueryInterface() Jörgen Sigvardsson15-May-04 13:21 Jörgen Sigvardsson 15-May-04 13:21  skruss wrote: Why not just using static_cast as well? It's a matter of taste really. They exist so that you can tell the compiler what it is that you want to accomplish. That way, the compiler can issue warnings/errors if what you want to do is illegal. Of course, dynamic_cast is slightly different from the other casting operators in that it actually does the cast in runtime (it returns 0 if A is not assignable to B - B* b = dynamic_cast<A*> reinterpret_cast should be avoided unless you really need it. Why? Because it basically tells the compiler to cast whatever into whatever. The compiler can thus not issue any warnings/errors. -- Booohoo! Beginning with COM or COM+ Mekong River13-May-04 15:48 Mekong River 13-May-04 15:48  hi, i want to learn COM from vb. does anyone know any usefull document that teach COM or COM+ from the beginner. some document that i had could not make the beginner like me to understand. please provide me any tips or trick to solve that problem. Roath Kanel APO-CEDC Save Children Norway-Cambodia Office USES_CONVERSION monrobot1313-May-04 11:35 monrobot13 13-May-04 11:35  I'm trying to use the conversion macros (OLE2A, OLE2CA, etc) and I know I need to add the USES_CONVERSION macro, but where do I put it? I put it in my header file and I keep getting compiler errors that a bunch of the variables it declares are missing their type-specifiers and such. Am I doing something wrong? Thanks. Also, this is off topic from the subject, but is there anything like CString for ATL? - Aaron Re: USES_CONVERSION Andrew Quinn AUS17-May-04 5:22 Andrew Quinn AUS 17-May-04 5:22  Aaron, In answer to the question of CString functionality for ATL, try looking at this (http://www.codeguru.com/Cpp/COM-Tech/atl/atl/article.php/c67/) I've used this in the past and worked a treat - Andy Re: USES_CONVERSION Roger Stoltz17-May-04 11:35 Roger Stoltz 17-May-04 11:35  monrobot13 wrote: I'm trying to use the conversion macros (OLE2A, OLE2CA, etc) and I know I need to add the USES_CONVERSION macro, but where do I put it? I put it in my header file and I keep getting compiler errors that a bunch of the variables it declares are missing their type-specifiers and such. Am I doing something wrong? Thanks. You place the USES_CONVERSION macro inside every function definition that will use conversion macros. For further reading I suggest Chris Maunder's article about "Unicode, MCBS and Generic text mappings" at http://www.codeproject.com/cpp/unicode.asp monrobot13 wrote: Also, this is off topic from the subject, but is there anything like CString for ATL? If you want something that comes with the ATL library I can't think of anything besides the CComBSTR, but I guess that is not what you are looking for. -- Roger Re: USES_CONVERSION Steve S17-May-04 23:26 Steve S 17-May-04 23:26  If you're using ATL 7.1 (VC++.NET 2003), then ATL has a common CString it shares with MFC. If you're using earlier versions (eg 3, from VC++6), then you can use WTL3.1 or 7.x which has a CString class also, somewhat lighter than using MFC in your app! Steve S Developer for hire Re: USES_CONVERSION Roger Stoltz18-May-04 0:20 Roger Stoltz 18-May-04 0:20  I'm still using the VC6, but it's good to know the alternatives. -- Roger Re: Thanks Everyone monrobot1320-May-04 6:49 monrobot13 20-May-04 6:49  Thanks for all the replies everyone. I forgot I posted this question here. - Aaron Writing files simultaneously 13-May-04 0:14 13-May-04 0:14  Hi I am using a COM component to upload files to website. I am writing all the files to a folder using "Binary Access Write" (VB) method. I am facing a problem. When a large file is being uploaded, no other file can be uploaded. The page times out. I want to make my site able to upload files simultaneously. Please give me advice on how to solve the problem. Thanks in advance. Mandar Date, Software Engineer Interface Methods monrobot1312-May-04 18:47 monrobot13 12-May-04 18:47  Two questions: One, can interface methods have default parameters? i.e. HRESULT MyMethod ([in] int size = 0) Two, can a class that implements an interface have a constructor with paramaters? Thanks! - Aaron Re: Interface Methods Roger Stoltz12-May-04 22:14 Roger Stoltz 12-May-04 22:14  monrobot13 wrote: Two questions: One, can interface methods have default parameters? i.e. HRESULT MyMethod ([in] int size = 0) Yes. Have a look at the MIDL keywords 'optional' and defaultvalue' in MSDN. Two, can a class that implements an interface have a constructor with paramaters? Regarding the C++ synthax and if you mean whether it will compile or not, the answer is yes. I don't see the use of it though. When the ClassFactory creates the object the default constructor will get called. It should be possible to modify the ClassFactory to call a constructor with parameters, but I don't know how much work that would be. I have a feeling that it would be much work for nothing since the same constructor will be called every time the object is created. Even if you take the long way of reading the registry by yourself to get the CLSID, calling CoGetClassObject and creating the object through the IClassFactory::CreateInstance method, there is no way you can pass parameters that can determine which constructor to call from the ClassFactory. Not through the COM-interfaces anyway. Technically you could have information elsewhere, e.g. in the registry, but I consider that an unstable solution and NOT recommendable. Consider who is responsible for that kind of information; if it's you, you can reproduce that information in your default constructor and if your user is responsible you have no control of the information and that would require a lot of error checking and fault tolerant code. And if it doesn't work, you would still be the one the user blames. -- Roger Re: Interface Methods monrobot1313-May-04 11:01 monrobot13 13-May-04 11:01  Thanks for the informative reply. - Aaron Re: Interface Methods Milton Karimbekallil12-May-04 23:13 Milton Karimbekallil 12-May-04 23:13  hi One - Yes, An interface method can have parameters with default values provided the parameter shud be optional too. The parameter settings while creating the function defenition in IDL is as fllows: [in] short i, [in] short j, [in, out, optional, defaultvalue(117)] short* k, [out, retval] short* l and the c++ function signature will be: STDMETHODIMP MyClass::Test(short i, short j, short *k, short *l) Two - A class that implimets an interface can have constructor with parameters. But no way to use that. If you use CoCreateInstance to create the client then we can't use the c++ class name directly and so cunstructor parameter also. Only way where we can use the c++ class name to create the com class is CComObject<MyClass>. But even this CComObject does not accept constructor initializers. rgds...mil10 Re: Interface Methods monrobot1313-May-04 11:02 monrobot13 13-May-04 11:02  Thanks much, the information is much appreciated. - Aaron MFC application to DCOM paulkned12-May-04 4:32 paulkned 12-May-04 4:32  Hi, I'm really new to DCOM but my boss wants me to get into it. so here's my question: I currently have a SDI MFC application which is a media player with DirectX, but that's beside the point. The thing is my boss wants me to implement the current application with some diagnostics software which has to call my application and pass along some values. The idea is to use DCOM as the interface between both applications but I'm kind of at a loss what I need to do now though. I've been reading some DCOM tutorials and I kind of understand how it works but I haven't been able to really find what I need to do to convert my current application to a component which understands messages it's sent. I'd be very greatful if anyone could help me or point me to some text on the internet which could help me. -Paul difference between MIDL Compiler Versions 6.00.0361 and 5.01.0164 Tarundeep Singh Kalra10-May-04 20:04 Tarundeep Singh Kalra 10-May-04 20:04  hi, this is my observation , correct me if i am wrong . I was defining a UDT which consist of a [uuid(D8B3861A-74C6-11d2-0000-00C04FB17CDB)] struct _BSSID_INFO { BSTR name; short grade; //classification type; VARIANT_BOOL graduate; }; in the IDL file. Now when i was compiling with Default Visual Studio IDE Compiler it gave the following errors :- error MIDL2072 : inapplicable attribute : [uuid] [ Struct '_BSSID_INFO' ] error MIDL2072 : inapplicable attribute : [uuid] [ Struct '_BSSID_INFO' ( Parameter 'bssid_info' ) ] warning MIDL2039 : interface does not conform to [oleautomation] attribute : [ Parameter 'bssid_info' of Procedure 'get_BSSID_INFO' ( Interface 'ICWiFiMgr' ) ] but when i compiled with new vesrion of compiler and replaced it with new MIDL.exe in the bin dir of VS6 it compiled correctly. Any Inputs -- Tarun.. Knowledge Seeker............ ********************************************************************** Tarundeep Singh Kalra (tarundeep1976_nospam_at_yahoo_dot_nospam_dot_com) tarun_at_tarunsadhana_dot_com visit:www.tarunsadhana.com ************************************************************************* Blue Pill or Red Pill........?? help Member 93959610-May-04 0:07 Member 939596 10-May-04 0:07  dear, i use .net framework v1.0.3705. win 2000 sp 4. i try to registry my dll with regasm or regsvcs. but, i have an error. "Strong name validation failed for assembly 'C:\WINNT\Microsoft.NET\Framework\v1.0.3705\RegAsm', The file may have been tampared with or it was partially signed but not fully signed with the correct private key." event if, i just run regasm or regsvcs from .net command prompt, i have a same error. please help me sir/madam...i really appreciate for your help. best regards Re: help Tuwing.Sabado8-Jun-04 17:37 Tuwing.Sabado 8-Jun-04 17:37  hi, I already saw this behavior when you referenced the System.EnterpriseServices without a strongname, the behavior of project act strangely, in design time the COM run smoothly but if you want to register your object into component services the problem occurs. The RegAsm utility show an error saying about strongname. The just add strongname to your project will solve your problem. mark Custom Interface in COM Exe shahzi9-May-04 23:05 shahzi 9-May-04 23:05  I am trying to implement a simple COM Application using Custome Interface and trying to get its object through CoCreateInstace(....). But it can get pointer to IUnknown interface but not the pointer to the COM Object. \ But the above scenerio works well in case of COM DLL Application. Kindly help me in this regard.

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