I've done my first DLL in C, it's very simple since it contains only two functions (sum and rest), I've tested it with Visual Basic and Delphi and it works, but I don't know how to use this DLL from a C program (console), is it possible to use a DLL from a console program or do I have to use a Windows program (WinMain)?
Anyone has an example of this (console or windows)? Thanks in advance for your help.
Geo.
You can call a dll from a console just like from a GUI. Either using a lib and compile time linkage or runtime linkage. Here's an example for runtime linkage
| CODE |
#include <windows.h>
int main()
{
HINSTANCE dll;
double (*MyFunction)(double,double);
//We load the dll
dll=LoadLibrary("hello.dll");
//We assign the function pointer
MyFunction=(double(*)(double,double))GetProcAddress(dll,"hello");
//We check if it worked
if(MyFunction==NULL)
return 0;
//We call it
(MyFunction)(115,546);
//We free the dll
FreeLibrary(dll);
system("pause");
return 0;
} |
Note that I only tested it for C++ but it should be C compatible
thanks for the comment, I'll try it and let you know how it works :).
------------------
Edit:
I've tried your example in a C program and it works great! Thanks a lot for your help. Yes, it works the same in C, here's my code:
| CODE |
#include <windows.h>
int main(int argc, char *argv[])
{
HINSTANCE dll;
void (*HelloWorld)(void);
dll = LoadLibrary("Cdll.dll");
HelloWorld = (void(*)(void))GetProcAddress(dll,"HelloWorld");
if(HelloWorld==NULL || Suma == NULL)
return 0;
(HelloWorld)();
FreeLibrary(dll);
system("PAUSE");
return 0;
}
|
The HelloWorld function looks like this (extracted from Dev-C++'s DLL template):
| CODE |
void HelloWorld ()
{
MessageBox (0, "Hello World from DLL!\n", "Hi", MB_ICONINFORMATION);
}
|
this function shows a Dialog using Win32 Api's MessageBox function.
I've also found info on how to link the DLL in compile time, thanks a lot dr voodoo!
José Jorge (Geo).
