Thank you so much for your answer, and for saving me a lot of time and trouble. You really went to the core of problem I am having. Unfortunately I worked for months to recode my program in separate DLL's in order to keep things separated. I personally think that DLL are also a mean to keep things separated, so to unify all of them in a unique DLL is something I will do only if I have no other choice. In my case I think I would rather find a way to eliminate the static member, even if it is really not a good solution because of the way my class is supposed to be used. Only a question. Why in Unix you didn't meet this problem ? ( I know a bit about Linux, but not very much. ) Best Regards, Marcello

:) Yes, I meant fvalerin

I just saw this article: Hooking the kernel directly http://www.codeproject.com/useritems/soviet\_direct\_hooking.asp maybe he can help you ! Marcello

Thank you for the all answers. But the question I made is not a beginner's question. It is about exporting a static variable and if there is any reason why it is made so difficult to export it. We know that it is possible to export a static member from a template class specialization, We know that it is not possible to use the __declspec(dllexport) keyword with a template. But in the example I gave I was able to get a static methods of a template exported even if the __declspec(dllexport) was not used. But this is not happening with a static data member. The reason I am trying to do this is that I need to export and use a class created by using the Curiously Recurring Template Pattern (CRTP). In my case the template base class needs to have a static member. About the third question, I am pretty sure that it is possible by using an export file (.def) and using a special keyword in it [ unfortunately I don't remember exactly how :( ]. Cheers, Marcello

Hello, Visual Studio 2005 From the help on: Compiler Warning (level 2) C4356 If I modify that example like:#include <iostream> template <class T> class C { static int n; }; class D : C<int> {}; // int D::n = 0; // C4356 int C<int>::n = 0;
if I take this code and put it in a DLL like this:// file mydll.h : # if defined(MYLIB_EXPORTS) # define MYLIB_API __declspec(dllexport) # else # define MYLIB_API __declspec(dllimport) # endif template <class T> class C { static int n; static void show() { std::cout << "C:show()" << std::endl; std::cout << n << std::endl; } }; class MYLIB_API D : C<int> {}; // file mydll.cpp : // initialization of static member int C<int>::n = 3; // file myapp.cpp : #include "mydll.h" int main() { int k1 = D::n; // (a) error LNK2001: unresolved external symbol int k2 = C<int>::n; // (b) error LNK2001: unresolved external symbol D::show(); // Okay }
The error I get, if I uncomment (a) or (b), is always: 1>myapp.obj : error LNK2001: unresolved external symbol "public: static int C<int>::n" (?n@?$C@H@@2HA) This makes sense because I am not exporting C. So the question is: 1.1) Why then method show() gets exported ? 1.2) In other words: Why the method gets exported and the data member not ? 2) Is there any way to export directly the data ? ( of course I could workaround the problem and access the static data member through a static method ) 3) A last question, a little different, but maybe related: If I try to export some data from a DLL, like: // file mydll.h : static MYLIB_API int mydata; // error C2201: 'mydata' : must have external linkage in order to be exported/imported MYLIB_API static int mydata2; // error C2201: 'mydata' : must have external linkage in order to be exported/imported I think that with vc70, if I remember well, I was not gettting any error message while compiling the DLL, but the LNK2001 error when linking the application. In other words I am always forced to export data as static data member of a class, ( which is in some cases very unconvenient), like:// file mydll.h : class MYLIB_API MyDataClass { static int data; }; // file mydll.cpp : int MyDataClass::data = 5;
Is there a way to do it without using a class ? Thank you very much for

Thank you very much for the reply. Please forget about the VCF::String thing. It was a typo on my side. Here is a code I made for this question ( it compiles class Cond { public: typedef std::basic_string MyString; Cond() { }; virtual ~Cond(void) { }; Cond( const Cond& other ) { /* simple implementation just for this example */ *this = other; }; Cond& operator= ( const Cond& other ) { return *this; }; // implementation bool split( const MyString& s, MyString::size_type* p = NULL ); bool split( MyString& s, const bool& trim ); }; inline bool Cond::split( const MyString& s, MyString::size_type* p ) { /* simple implementation just for this example */ return true; } inline bool Cond::split( MyString& s, const bool& trim ) { MyString::size_type p; //if ( split( const_cast(s), &p ) ) // this compiles fine if ( split( s, &p ) ) // C2666 { s = s.substr( p + 1 ); return true; } return false; } I get the error message: 1>d:\projs\libraries\vcfex\src\conditions\test.h(51) : error C2666: 'vcfex::Cond::split' : 2 overloads have similar conversions 1> d:\projs\libraries\vcfex\src\conditions\test.h(37): could be 'bool vcfex::Cond::split(vcfex::Cond::MyString &,const bool &)' 1> d:\projs\libraries\vcfex\src\conditions\test.h(36): or 'bool vcfex::Cond::split(const vcfex::Cond::MyString &,stlp_std::basic_string<_CharT,_Traits,_Alloc>::size_type *)' 1> with 1> [ 1> _CharT=wchar_t, 1> _Traits=stlp_std::char_traits, 1> _Alloc=stlp_std::allocator 1> ] 1> while trying to match the argument list '(vcfex::Cond::MyString, stlp_std::basic_string<_CharT,_Traits,_Alloc>::size_type *)' 1> with 1> [ 1> _CharT=wchar_t, 1> _Traits=stlp_std::char_traits, 1> _Alloc=stlp_std::allocator 1> ] 1> note: qualification adjustment (const/volatile) may be causing the ambiguity It puzzles me that the C++ standard ( or is just vc80 ? ) is asking me to specify const_cast when intuitively the compiler should resolve the two overloads 'without effort'. A comment on this after the next point. I understand what you say at the second point. I agree but I am really surprised at the same time. I always considered a const function just as a way to tell the compler that that function is not going to change the 'this' pointer. So I ca

Hello, a question around the error C2666, under vc80 (RTM-8.0.50727.4200) Is it compliant to the C++ standard ? class CondParams { ... static bool getVariableState( const string& s, int& idx, string::size_type* p = NULL; // A static bool getVariableState( string& rs, int& idxVar, const bool& trim ); // B ); bool CondParams::getVariableState( string& rs, int& idx, const bool& trim ) { ... VCF::String::size_type p = 0; bool ok = getVariableState( rs, idx, &p ); if ( ok ) rs = rs.substr( p ); ... } I get the error message: 1>d:\projs\condparams.cpp(66) : error C2666: 'vcfex::CondParams::getVariableState' : 2 overloads have similar conversions 1> d:\projs\code\condparams.h(130): could be 'bool vcfex::CondParams::getVariableState(string &,int &,const bool &)' 1> d:\projs\code\condparams.h(129): or 'bool vcfex::CondParams::getVariableState(const string &,int &,string::size_type *)' 1> while trying to match the argument list '(string, int, size_type *)' 1> note: qualification adjustment (const/volatile) may be causing the ambiguity I could fix the problem by doing: 1) static bool getVariableState( string& s, int& idx, string::size_type* p = NULL; // A or by doing: 2) bool ok = getVariableState( const_cast(rs), idx, &p ); so I guess that the compiler is confused because it doesn't find any perfect match. The solution 1 is usually not acceptable. So I have to apply 2). But this situation is *very* common: why should I need to specify that a variable is constant each time I am using it as argument for a function that declared that is not going to modify it ? Also it doesn't logically seem necessary. It is like the Standard C++ ( or Microsoft? ) is forcing me to put a const_cast everywhere. This was not a problem with vc70. Similar issue, but not identical, with an example given in vc80 RTM help about the C2666 error. enum E { E_A, E_B }; class A { int h(const E e) const {return 0; } int h(const int i) { return 1; } // Uncomment the following line to resolve. // int h(const E e) { return 0; } void Test() { h(E_A); // C2666 h((const int) E_A); h((int) E_A); } }; Why the compiler shouldn't be smart enough to understand that int h(const E e) is a better match than int h(const int i) ? Why in earth int h(const E e) solves the problem, while int h(const E e) co

Problem solved ! I had the feeling that vc70 was not reading this darn definition file, because by changing it it was not asking to rebuild. So I looked around and I found the option: Property Pages > Linker > Input > Module Definition File > and there I put AutoExp.def where the content is: LIBRARY AutoExpEx DESCRIPTION "Implements Custom Evaluator for Microsoft Debugger" EXPORTS VCF_VariantEvaluate @1 It works ! The linker screams both with the DLLEXPORT declaration and/or I do not use the '@' Note that the help in VisualStudio says that we should not specify the file in the environment, only to include it into the project ! But it works. Thanks a lot ! I really appreciated !

Tried ! No success !

What a cool program ! I dodn't know about it ! Thank you ! Under Depends it shows exactly as with dumpbin vc6: it appears as VCF_DateTimeEvaluate vc70: it appears as _VCF_DateTimeEvaluate@28

Thank ou for all the help. I will try to check what you suggested me tomorrow ! Cheers, Marcello

Thank you very much. At least an answer ! But it doesn't work :( This is my definition file for vc70: AutoExp.vcproj, AutoExp.cpp and AutoExp.def are all in the same directory AutoExp.vcproj has AutoExp.cpp and AutoExp.def in itself. Is there, maybe, some options in the project that creates problems ? Cheers, Marcello

I am not a C++ guru, but this is how I understand the problem. You have a diamond pattern: I1 / \ I2 C1 \ / C2 I1::f=0 I2 f=? C1 f={} C2 ( f = I2::f or C1::f ? ) which you should always try to avoid when you use multiple inheritance. BTW: many people complain about multiple inheritance, but as long as you avoid a diamond patter, you'll be fine. So C2 is asking which f() should I make visible ? Your answer is: the one implemented. But this you know it only at linkage time. You need to implement f also in I2 and still you'll get an error because you still didn't answer the question ( f = I2::f or C1::f ? ) So you need to implement C2::f() { return C1::f(); } or you need to delete the declaration of f() in I1 Hope it clarifies.

Hello, I am using the tecnique http://www.lambdasoft.dk/comet/doc/cometautoexp.html in order to provides custom formatting for variables in the VisualStudio debugger. I can tell that it works very well. What puzzles me is this. In the code I export the function from the DLL in this way: extern "C" { __declspec(dllexport) HRESULT WINAPI VCF_DateTimeEvaluate( DWORD dwAddress, DEBUGHELPER *pHelper, int nBase, BOOL bUniStrings, char *pResult, size_t maxlen, DWORD reserved ); } But then: dumpbin /exports AutoExp.dll shows _VCF_DateTimeEvaluate@28 instead than simply VCF_DateTimeEvaluate both by compiling with vc6 and vc70. Other people swear that I should simply get VCF_DateTimeEvaluate as long as I use: extern "C" { ... } Please note that extern "C" does something anyway, because without it I would get the mangled name: ?VCF_DateTimeEvaluate@@YGJKPAUtagDEBUGHELPER@@HHPADIK@Z If you have the patience to answer to another related question, here it is ! If I do use a definition file, it works with vc6 by just including it in the project, as I get: VCF_DateTimeEvaluate But with vc70 it doesn't work. Why ? What should I do different ?

Did you notice that some applications like yours they eject the CD when they are finished ? And then they close the tray again ? Like Nero. Maybe because of the same problem you have. And most of applications playing music ( even Windows Media Player and NeroMix ) have the same problem. They have problems to automatically update their music list once he CD is inserted. It doens';t always work. M

Other people can answer you better than me. But I noticed that you "get the value of the variable. Instead I get the variable declaration information. " when the variable is nto valid at that moment, like a NULL pointer. For the second, look for the edit and continue compiler option and look also for the conditions when this is disabled.

Hello, sorry for posting this here. The question is: how to replace malloc with the Lea's allocator malloc ? http://gee.cs.oswego.edu/dl/html/malloc.html I tried everything but it doesn't work. I even posted this question to the author of its malloc replacement, Lea Dough. But my question is more windows related so he cannot answer me. At the same time I know that somebody here has been able to do it. Here is the list of what I did and of what some related question. But really what matter is that somebody is telling me how to do it. I am building a program build on top of other dynamic libraries. Everything using STLport. I created another static library, or dynamic I made as very first line of code in the first #if defined(USE_LEA) && defined(_WIN32) #pragma comment(lib, "libLea.lib") #endif If I #include malloc.h then I have compilers problem ( probably because the library is using precompiled headers ) like: c:\Program Files\Microsoft Visual Studio .NET\Vc7\include\stdlib.h(291): error C2375: 'malloc' : redefinition; different linkage If I do not #include malloc.h then it compiles but at the end it is not using the malloc of Lea. I would like not to use detour. I don't think is a good idea to replace malloc.c malloc.h in the Visual Studio .NET\Vc7\include directory Can somebody help me ? Thanks a lot. Cheers, Marcello

Thank you, I am realizing now that with Mozilla browser only the smileys appears, not the others.

How do I add an achor tag ? How do I write a [code] section, which appears in light yellow if I remember well Is there a link that explains all of these things and others ? Thanks !

Click on the smiling icon ! http://www.codeproject.com/gdi/screencolorpicker.asp The Code Project - Screen Color Picker - Fonts & GDI