But If I use it in PureBasic 4.20 (beta1) I got an error:
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Unhandled exception at 0x0041364b in polink.exe: 0xC0000005: Access violation reading location 0x0286d9b9.
A.I wrote:Tutorial
This is a simple tutorial on how to create a simple Userlib in Microsoft Visual C++ 6.0. We'll make a DLL that has only one function: HelloWorld(), which takes one integer parameter and returns it double back to PureBasic. For example, if you passed integer 6 it would return 12 and so on.
I'm a bit of a beginner in C++ as well and there's probably many PB users that would do things differently. Feel free to correct my mistakes or post advices.
This tutorial will advance step by step just in case you don't have that much knowkedge on VC++ and/or its user interface.
Step 1: Create a new project
1) Open VC++
2) Click File/New
3) Select Win32 Dynamic-Link Library
4) Choose a project name. I use "PBHello" here.
5) You'll be asked what type of DLL project you'd want create. Select "A simple DLL project"
Now, you should have a single project created for you. At the left you see ClassView and FileView. Click on FileView and then the project name (PBHello). DoubleClick on PBHello.cpp so we can start coding...
Step 2: Code skeleton
Add these (leave the APIENTRY):
Step 3: Project setupCode: Select all
char *PB_DEBUGGER_ErrorDescription; HWND PB_DEBUGGER_Window; int PB_DEBUGGER_Control; void SendDebuggerError(char*); void SendDebuggerError(char *text) { if (PB_DEBUGGER_ErrorDescription == 0) { PB_DEBUGGER_ErrorDescription = text; PB_DEBUGGER_Control = 2; // Halt the PureBasic program flow... SendMessage(PB_DEBUGGER_Window, WM_COMMAND, 6, 1); } }
In order to link and Build the DLL correctly (from the view of PureBasic) we need to set a few things up.
1) Select the project PBHello from the list on the left
2) Go Build/Configurations
3) Select "Win32 Debug" and remove it
4) Confirm and Close
5) Go Project/Settings
6) Select C/C++ tab
7) Select Category-combo/Code Generation
8 ) Set Calling Convention to __cdecl (if it's not)
9) Set Runtime-library to "Multithreaded DLL"
10) Select the Link-tab
11) Add MSVCPRT.LIB to "Object/Library modules"
12) The output file name can be just "PBHello.dll"
13) OK
Step 4: Writing the code
Each procedure/function must come in pairs: the procedure itself and its corresponding debug-version for PureBasic Debugger.
The actual procedure must use _stdcall in order to work. However, the debug function should use __cdecl convention (but don't you worry about that, we've already chosen it to be the default).
Also, the debug-function must be the type of void, so it wouldn't return anything. I'm not exactly sure how the debug thingy works, but I just check if the parameters are valid, or something... You can simply write an empty debugger function.
Always remember to put PB_ prefix to the function names. Write the following code:
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extern "C" int _stdcall PB_HelloWorld(int x) { return x*2; } extern "C" void PB_HelloWorld_DEBUG(int x) { }
1) the PB_ prefix
2) _stdcall for the actual functoin (omitted in the debugger function)
3) debugger function postfix _DEBUG
4) debugger function void type (and not returning a value)
Step 5: Compile
Save and hit F7 to build. There should be no errors.
You could get warning "all references to "USER32.dll" discarded by /OPT:REF" but you can ignore it (Hit F7 again).
Go to:
"C:\Program Files\Microsoft Visual Studio\MyProjects\PBHello\Release"
(or whatever the path is)
..and see there are at least PBHello.dll and PBHello.obj
Step 6: The .Desc-file
Create a new file called PBHello.Desc into that directory.
Write this:The Readme.txt has description of the .Desc file format, but I find it quite a mess (no offence, FredCode: Select all
C 1 MSVCRT OBJ 0 Extension1 ; HelloWorld, Long (integer) - Doubles the given integer Long | DebuggerCheck
viewtopic.php?t=15150
Our Desc-file suggests that PBHello -function requires one parameter (Long), and returns Long. For some reason I can't compile Userlibs that omit the "|DebuggerCheck" -part, so I wrote it here, too.
If you wish to omit the quick command help, just discard all starting from "-" (still include the parentheses).
Step 7: LibraryMaker
You can find it in PureBasic\Library SDK
The objects path should be the same (notice the tailing backlash):
"C:\Program Files\Microsoft Visual Studio\MyProjects\PBHello\Release"
Enable compression, it's cool.
Hit Start and select the Desc-file from the right directory. If everything went OK, you should get no messages of any kind. Go and see PureBasic\PureLibraries. There should be PBHello. If you wish, you can move it to the Userlibraries -folder.
Step 8: Test
Now, restart PB compiler or the IDE in order to get the PureBasic compiler to recognize our new command HelloWorld.
Test with this code (debugger on and off):
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i=HelloWorld(34) MessageRequester("",Str(i))
There's still lots of questions I need to find an answer. This was my first attempt of creating a Userlib for PureBasic. This is just how I did it. I hope this proofs usefuls for all you who want to start expanding PureBasic with C++ code
See ya.
