I'm trying to get my executeable file to load a few DLLs I have made and compiled so that I don't have to put a ton of functions into the actual executeable, but I have NO experience with DLLs. Can somebody help me figure out how to use both load-time linking (Borland says I have to link with the .LIB for this one?) and run-time linking (for stuff such as the main menu popping up when you press ESC). I would REALLY appreciate any help that anybody can give me. Thanks for your time.<br>
<br>
-Seph

Hello Speh..<br>
<br>
For linking in compile time, you only need to add the lib file to your project, then #include the header file and off you go. For example, you have a void myfunc( int x ) in the DLL, your include file will look like this:<br>
// mydll.h<br>
#if !defined( INC_MYDLL )<br>
#define INC_MYDLL<br>
<br>
#if defined( __cplusplus )<br>
extern "C" {<br>
#endif // __cplusplus<br>
<br>
// list the functions here<br>
void WINAPI myfunc( int x );<br>
<br>
#if defined( __cplusplus )<br>
}<br>
#endif // __cplusplus<br>
<br>
#endif // INC_MYDLL<br>
<br>
If you have a problem with any of the above, post again!<br>
<br>
If you want to use a DLL created by someone else, then dont forget to IMPLIB it beforehand. BCB and VC++ both use different format for thier import libraries.<br>
<br>
To use the DLL above in run-time, you would do it like this:<br>
<br>
typedef void (*WINAPI pMYFUNC)( int );<br>
<br>
HINSTANCE hInst = LoadLibrary( "mydll.dll" );<br>
pMYFUNC pMyFunc = (pMYFUNC) GetProcAddress( hInst, "myfunc" );<br>
<br>
// and run it..<br>
pMyFunc(10);<br>
<br>
// You might want to do this before you are done<br>
FreeLibrary( hInst );<br>
<br>
I didnt understand what you mean by main menu and ESC...<br>
<br>
Hope this helped a bit

OK, I didn't make a header file for the dll before. All I did was make a file with the functions in it, and then compiled to a dll, with no errors or warnings. So what would this header file be used for? Just linking purposes??<br>
<br>
-Seph<br>
<br>

That header file is the interface to your DLL. Remember, a DLL is a library, and a library is all about packaging some piece of code from the user with only an interface exposed.<br>
<br>
For example, GDI.EXE (its a DLL renamed EXE really) is the DLL, windows.h is the interface that has the prototypes of the functions inside that DLL, like int WINAPI SetPixel( HDC hDC, int x, int y );<br>
<br>
: OK, I didn't make a header file for the dll before. All I did was make a file with the functions in it, and then compiled to a dll, with no errors or warnings. So what would this header file be used for? Just linking purposes??<br>
: <br>
: -Seph<br>
: <br>
: <br>
: <br>
<br>

So it would be like this?<br>
<br>
//the dll itself<br>
int hitval(int level, int str, int agi, int opagi)<br>
{<br>
stuff here;<br>
return hit;<br>
}<br>
<br>
<br>
//the header<br>
*stuff you showed me here*<br>
int hitval(int level, int str, int agi, int opagi);<br>
<br>
<br>
I'm going to try it real fast and see what happens. This "fight.dll" is very important to the program though, considering it has all battle info in it.<br>
<br>
-Seph

OK, just got done trying it. I pasted what you posted into the header file, and changed it from INC_MYDLL to INC_FIGHT (fight.dll/fight.cpp) and the void function I replaced with "int hitval(int level, int str, int agi, int opagi);". I am still getting "unresolved external referenced from AoY.OBJ". I have added the .lib file to the project, to be linked with the executeable. Any ideas??<br>
<br>
-Seph

You still need to tell the compiler which functions to export from the DLL. This can be done in 2 ways, the __dllimport/__dllexport or through a DEF file, I use DEF files always because it lets me define the ordinal numbers of those functions myself, meaning, if I update the DLL by adding new functions, the EXE's need not to be recompiled. A good practice!<br>
<br>
OK, lets write this down.. I think you know how to create a Win32 DLL project, so here are the files to add.<br>
<br>
First of all here's the H file:<br>
//----------------------------------------------------------------------------<br>
// fight.h<br>
#if !defined( INC_FIGHT )<br>
#define INC_FIGHT<br>
<br>
#if defined( __cplusplus )<br>
extern "C" {<br>
#endif // __cplusplus<br>
<br>
int WINAPI hitval(int level, int str, int agi, int opagi);<br>
<br>
#if defined( __cplusplus )<br>
}<br>
#endif // __cplusplus<br>
<br>
#endif // INC_FIGHT<br>
//----------------------------------------------------------------------------<br>
<br>
And the CPP file<br>
//----------------------------------------------------------------------------<br>
// fight.cpp<br>
#include <windows.h><br>
#include "fight.h"<br>
<br>
extern "C"<br>
int WINAPI hitval(int level, int str, int agi, int opagi)<br>
{<br>
// for a test, show values in a message box<br>
char buffer[ 80 ];<br>
wsprintf( buffer,<br>
"level = %d\nstr = %d\nagi = %d\nopagi = %d",<br>
level, str, agi, opagi );<br>
MessageBox( NULL, buffer, "in dll", MB_OK );<br>
<br>
return 10;<br>
}<br>
//----------------------------------------------------------------------------<br>
<br>
And the DEF file<br>
;----------------------------------------------------------------------------<br>
; fight.def<br>
LIBRARY FIGHT.DLL ; should be the same name as the result DLL!<br>
DESCRIPTION 'This is the fight DLL!'<br>
HEAPSIZE 10000<br>
EXPORTS<br>
hitval @100 ; you can add more functions here: function name @101 and so on<br>
;----------------------------------------------------------------------------<br>
<br>
Note that comments in DEF file are ; comment... much like ASM comments.<br>
<br>
That's it, compile/link the lot, you have a DLL and a LIB file. Now create a simple test EXE something like this<br>
// ----------------------------------------------------------------------------<br>
// test.cpp<br>
#include <windows.h><br>
#include "fight.h" // make sure this points to the correct path<br>
<br>
int WINAPI WinMain( HINSTANCE, HINSTANCE, LPSTR, int )<br>
{<br>
int ret = hitval( 1, 2, 3, 4 );<br>
char buffer[ 80 ];<br>
wsprintf( buffer, "returned %d", ret );<br>
MessageBox( NULL, buffer, "in exe", MB_OK );<br>
return 0;<br>
}<br>
//----------------------------------------------------------------------------<br>
<br>
Add fight.lib to this project, make sure fight.dll is somewhere along the path, run.. It should work fine.<br>
<br>
Hope this helps<br>
<br>
: OK, just got done trying it. I pasted what you posted into the header file, and changed it from INC_MYDLL to INC_FIGHT (fight.dll/fight.cpp) and the void function I replaced with "int hitval(int level, int str, int agi, int opagi);". I am still getting "unresolved external referenced from AoY.OBJ". I have added the .lib file to the project, to be linked with the executeable. Any ideas??<br>
: <br>
: -Seph<br>
: <br>
<br>

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