Euphoria DLL Howto

Here is an introduction to writing a dll using Euphoria.
This is not to be confused with using an existing Windows dll or Linux .so library.

Tools needed

• Euphoria 4.02
• Openwatcom C win32 1.9

Step 1. Creating a simple DLL using Euphoria

Open your favorite text editor an enter following lines:

include std/console.e 
constant SCREEN = 1 
 
global procedure HelloWorld() 
puts(SCREEN, " \n Hello, World! \n") 
any_key() 
end procedure 

Now, save the file with targetDLL.ex name.
Open command prompt, navigate to the folder where targetDLL.ex located (leave it opened for further usage). Translate the Euphoria code to C and compile it as DLL using following command:

euc -con -dll targetDLL.ex 

• euc - is a Euphoria to C translator
• -con - to state that we do not want the GUI
• -dll - to state that we want to create a DLL

You should see the output like following:

Build directory: build-433938\ 
Translating code, pass: 1 2 3 4  generating 
Compiling with Watcom 
Compiling   1% init-.c 
Compiling   7% targetDLL.c 
Compiling  11% main-.c 
Compiling  15% console.c 
Compiling  19% get.c 
Compiling  23% error.c 
Compiling  26% io.c 
Compiling  30% machine.c 
Compiling  34% memconst.c 
Compiling  38% memory.c 
Compiling  42% dll.c 
Compiling  46% types.c 
Compiling  50% text.c 
Compiling  53% convert.c 
Compiling  57% search.c 
Compiling  61% filesys.c 
Compiling  65% datetime.c 
Compiling  69% math.c 
Compiling  73% rand.c 
Compiling  76% sequence.c 
Compiling  80% sort.c 
Compiling  84% wildcard.c 
Compiling  88% pretty.c 
Compiling  92% serialize.c 
Compiling  96% graphcst.c 
Linking 100% ..\targetDLL.dll 

The test DLL is ready, we can go to next step.

Step 2. Using your external DLL with a Euphoria program

Open the text editor and enter following lines:

include std/dll.e 
 
atom thedll 
integer theroutine 
 
-- step 1. Open the DLL 
thedll = open_dll("targetDLL.dll") 
-- step 2. Define the routine inside the DLL 
theroutine = define_c_proc(thedll , "HelloWorld", {}) 
-- step 3. Execute the routine 
c_proc(theroutine) 

Now, save the file with openDLL.ex name, and execute it in command prompt:

openDLL.ex 

 Hello, World! 
Press Any Key to continue... 

Conclusion

Thats all. We called C procedure "HelloWorld", stored in compiled DLL file from the Euphoria program. This is the basics, it does not cover how to handle the variables, it does not cover how to deal with "real" C/C++ coded DLLs, and I'd like that basics will be extended in following way:

• Include some variables to deal with it
• Build the test DLL using C-source code and with MinGW
• Build the test DLL using C++ source code and with MinGW
• Finally (to make it brilliant) create a real step by step example based on some popular DLL (ex. lame)