[fabian.rap.more]

I am using this IDE to write some c++ programs: http://www.bloodshed.net/devcpp.html

I have a program that I need to put into a dll file under a function so that I can call it from any application. How do I do this? Is there any tutorial for this? I would also like to be able to add more functions to this dll file.

Thanks in advance.

[Shadow2531]

Here's a c++ example of how to create a dll with Mingw and use it. (Bloodshed uses Mingw)

mytestlibrary.hh:

#ifndef MYTESTLIBRARY_HH
#define MYTESTLIBRARY_HH

#include <iostream>

void test();

#endif

mytestlibrary.cc:

#include "mytestlibrary.hh"

void test() {
    std::cout << "My test library!\n";
}

g++ -Wall -Wextra -shared mytestlibrary.cc -o mytestlibrary.dll -O3 -s -Wl,--out-implib,libmytestlibrary.a,--output-def,mytestlibrary.def

Now that you've built the library, install it.

Put mytestlibrary.hh in a mytestlibrary folder in the compiler's include folder.

Put libmytestlibrary.a and mytestlibrary.def in the compiler's lib folder. (.def file is useful for generating a .lib file that MSVC can link to. Not needed for Mingw.)

Now, create a program that uses the library.

mytestprogram.cc:

#include <mytestlibrary/mytestlibrary.hh>

int main() {
    test();
}

g++ -Wall -Wextra mytestprogram.cc -o mytestprogram -O3 -s -lmytestlibrary

Make sure mytestlibrary.dll is in the same directory as mytestprogram.exe and run mytestprogram.exe

To add more functions to the dll, just declare more in the hh file, implement them in the cc file, rebuild the dll, install it and rebuild the test program.

If you want to add a function to a .dll that you don't have the source to and can't build, I'm not sure.

[fabian.rap.more]

Ok. Thank you very much. It worked.

[fabian.rap.more]

One more thing. I need to pass a few parameters. I tried putting test(int no); but no luck.

And from some applications it appears like this: Mylibrary::_Z6testv

How do I fix this?

[Shadow2531]

One more thing. I need to pass a few parameters. I tried putting test(int no); but no luck

Did you make the change in *both* the hh and cc files?

And from some applications it appears like this: Mylibrary::_Z6testv

I think you have to use extern C if you want the names to come out unmangled. You might have to do some other things depending on what compiler built the program that's loading your mingw dll.

This will explain:
http://en.wikipedia.org/wiki/Name_ma...ing_in_C.2B.2B

[fabian.rap.more]

I get the following errors:

D:\Mydlls\/mytestlibrary.hh:6: error: previous declaration of `void* Create()' with C++ linkage
D:\Mydlls\mytestlibrary.cc:9: error: conflicts with new declaration with C linkage

[fabian.rap.more]

And I tried adding each parameter to both the files but it gives me ALOT of errors.

[Shadow2531]

Try the attached.

[fabian.rap.more]

OK. This is my last requirment:

I need to pass a string name to the dll and this string will be a file name but I can't pass a string though I tried const string file and const char file

Also I can't open a file whose name is stored in a variable. I open files using: std:fstream myf ("name.txt");

[Shadow2531]

Try the attached to see if that gives you an idea.

Also, note that in testloadlibrary.cc,

MYFUNC writeFile = (MYFUNC)GetProcAddress(mydll, "writeFile");

should probably be:

MYFUNC writeFile = reinterpret_cast<MYFUNC>(GetProcAddress(mydll, "writeFile"));

You can catch that by building with -Wold-style-cast

[fabian.rap.more]

Thanks. It works now

[fabian.rap.more]

And also thank you so much for helping me