How to Access class in a Dll?

[Nobody/Anonymous]

I've make a dll project using Dec-C++ C++ Template,Then I create a Console project to test the dll,I add the dll file created and the associated .a file ,.h file to the Console project's directory,at the Dev-C++ "Project Options" I add the param -llibDll2,then press the button "Add Library or Object",select the file libDll2.a,I rebuild all,
but error occurs.The following is the building log:
Compiler: Default compiler
Building Makefile: "C:\Console1\Makefile.win"
Executing  make clean
rm -f main.o  Console1.exe

g++.exe -c main.cpp -o main.o -I"C:/Dev-Cpp/include/c++"  -I"C:/Dev-Cpp/include/c++/mingw32"  -I"C:/Dev-Cpp/include/c++/backward"  -I"C:/Dev-Cpp/include"  -I"C:/Dev-Cpp/winh"   -gstabs -g3 -O0

g++.exe main.o  -o "Console1.exe" -L"C:/Dev-Cpp/lib" -L"C:/Dev-Cpp/winlib" -llibDll2 libDll2.a

C:\Dev-Cpp\Bin\..\lib\gcc-lib\mingw32\3.2\..\..\..\..\mingw32\bin\ld.exe: cannot find -llibDll2

make.exe: *** [Console1.exe] Error 1

Execution terminated

Anybody would give me some advice?

[Georhan]

Hi :)
You don't need to specify both -llibDll2 and "PATH\libDll2.a" to the linker options.
just delete -llibDll2 and this should work.
Moreover, if you choose to delete libDll2.a, then :
- add (I don't know if it's REALLY useful) the directory where this file is in the project options -> directories -> library dierctory
- specify -lDll2 to the linker option ('lib' mustn't be there).

Georhan

[Nobody/Anonymous]

Thanx for you reply. I did it as you told me,but new problem appears.

Compiler: Default compiler
Building Makefile: "C:\Console1\Makefile.win"
Executing  make clean
rm -f main.o  Console1.exe

g++.exe -c main.cpp -o main.o -I"C:/Dev-Cpp/include/c++"  -I"C:/Dev-Cpp/include/c++/mingw32"  -I"C:/Dev-Cpp/include/c++/backward"  -I"C:/Dev-Cpp/include"  -I"C:/Dev-Cpp/winh"   -gstabs -g3 -O0

g++.exe main.o  -o "Console1.exe" -L"C:/Dev-Cpp/lib" -L"C:/Dev-Cpp/winlib" libDll2.a

main.o(.text+0x2d): In function `main':
C:/Console1/main.cpp:9: undefined reference to `DllClass::DllClass()'

main.o(.text+0x3c):C:/Console1/main.cpp:10: undefined reference to `DllClass::HelloWorld()'
main.o(.text+0x5b):C:/Console1/main.cpp:12: undefined reference to `DllClass::~DllClass()'
main.o(.text+0x72):C:/Console1/main.cpp:12: undefined reference to `DllClass::~DllClass()'

make.exe: *** [Console1.exe] Error 1

Execution terminated

//the define file of dll project,i'v added it into my test console project
#ifndef _DLL_H_
#define _DLL_H_

#if BUILDING_DLL
# define DLLIMPORT __declspec (dllexport)
#else /* Not BUILDING_DLL */
# define DLLIMPORT __declspec (dllimport)
#endif /* Not BUILDING_DLL */

class DLLIMPORT DllClass
{
  public:
    DllClass();
    virtual ~DllClass(void);
    void HelloWorld(void);
  private:

};

#endif /* _DLL_H_ */

//the file to access class in dll.
#include <iostream>
#include <stdlib.h>
#include "dll2.h"

using namespace std;

int main(int argc, char *argv[])
{
  DllClass test;
  test.HelloWorld();
  system("PAUSE");   
  return 0;
}

[Georhan]

Arf the old bugs reappear ! :)
Just add -DBUILDING_DLL in the C++ compiler options (you find it in the C compiler by default)

Georhan.

[Nobody/Anonymous]

Georhan,hi,I add the option _DBUILDING_DLL in the C++ compiler options,but it still failed to compile.
I use Dev-C++ 4.9.8.0, can you help me?

Compiler: Default compiler
Building Makefile: "C:\Console1\Makefile.win"
Executing  make clean
rm -f main.o  Console1.exe

g++.exe -c main.cpp -o main.o -I"C:/Dev-Cpp/include/c++"  -I"C:/Dev-Cpp/include/c++/mingw32"  -I"C:/Dev-Cpp/include/c++/backward"  -I"C:/Dev-Cpp/include"  -I"C:/Dev-Cpp/winh" -DBUILDING_DLL   -gstabs -g3 -O0

g++.exe main.o  -o "Console1.exe" -L"C:/Dev-Cpp/lib" -L"C:/Dev-Cpp/winlib" libDll2.a

main.o(.text+0x2d): In function `main':
C:/Console1/main.cpp:9: undefined reference to `DllClass::DllClass()'

main.o(.text+0x3c):C:/Console1/main.cpp:10: undefined reference to `DllClass::HelloWorld()'
main.o(.text+0x5b):C:/Console1/main.cpp:12: undefined reference to `DllClass::~DllClass()'
main.o(.text+0x72):C:/Console1/main.cpp:12: undefined reference to `DllClass::~DllClass()'
main.o(.data$_ZTV8DllClass+0x8):C:/Console1/main.cpp:8: undefined reference to `DllClass::~DllClass()'
main.o(.data$_ZTV8DllClass+0xc):C:/Console1/main.cpp:8: undefined reference to `DllClass::~DllClass()'

make.exe: *** [Console1.exe] Error 1

Execution terminated

[Liviu Nicolescu]

Georhan meant to say to add -DBUILDING_DLL=1 in the C++ compiler options when compiling the dll.

You will find here how to create/use a simple dll:

http://sourceforge.net/forum/message.php?msg_id=2535537

Liviu

[Nobody/Anonymous]

Liviu,Thank you. I'v got it run correctly. In fact, I did like All those of the tutor steps but one,In building the Dll project, in the "Parameters" option tab->c compiler parameter,by default,the -DBUILDING_DLL is set, I moved it into the C++ compiler parameter,rebuild all,rebuild the console,it success. that's really a good tutor for our newbies,thank you a second time.