Unable to pass string parameters to Clarion Dll from C#

questions
1

I have a Clarion Dll and I need to call a procedure inside of it from C# (I have access to both of the codes).

It works perfectlly if I don`t try to pass any paramters to the procedure.

This is the actual Clarion code, it has nothing inside, I am using it just for testing purposes.

AtualizaEstoqueNovo_Teste PROCEDURE  (string pr)           ! Declare Procedure
    CODE

The procedure MAP declaration.

50A5C8 ATUALIZAESTOQUENOVO_TESTE@Fsb

From the C# end, I am declaring an extern void function.

[DllImport("C:\\Tests\\48\\prog\\ss007.dll", EntryPoint = "ATUALIZAESTOQUENOVO_TESTE@FSB")]
    public static extern void ATUALIZAESTOQUENOVO_TESTE(string pr);

I am calling it like any other function

ATUALIZAESTOQUENOVO_TESTE("");

It throws me the error “Unable to find an entry point named “ATUALIZAESTOQUENOVO_TESTE@FSB””

The funny thing is that if I try to do the same thing but without using any paramters, it works.

[DllImport("C:\\Tests\\48\\prog\\ss007.dll", EntryPoint = "ATUALIZAESTOQUENOVO_TESTE@F")]
    public static extern void ATUALIZAESTOQUENOVO_TESTE();

I really don`t know what I am missing.

Also, the C# code is inside a Windows Service, but I think that shouldn`t matter

2

I’m sure someone that has done this will jump in …

The name is case sensitive so you need “@Fsb” not upper “@FSB”. That is not your only problem…

A Clarion STRING is not the same as a C# String. You will want to use a CSTRING in Clarion and in C# Marshall it as an ANSI Null Terminated String.

Your Clarion type will change to below. You must pass by Address hence the * Asterisk. You need RAW or Clarion expects the CString Size as another parameter (hidden in Clarion code):

AtualizaEstoqueNovo_Teste PROCEDURE(*CString pr),RAW,PASCAL

The mangled export symbol name should be ATUALIZAESTOQUENOVO_TESTE
but check the MAP or EXP file to be certain. Remember it’s Case Sensitive.

A better alternative would be to use a BSTRING in Clarion and Marshal it as a Unicode BSTR from C#. RAW is not required on a BSTRING it only passes the address and no length (the length is built into the BSTR type).

AtualizaEstoqueNovo_Teste PROCEDURE(*Bstring pr),PASCAL

and the mangled export symbol name should be ATUALIZAESTOQUENOVO_TESTE
but check the MAP or EXP file to be certain.

Edit 2:00 pm
Added PASCAL per Oggy to correct these examples which removes @Fxxx from the mangled name. Also PASCAL is important for proper stack cleanup otherwise you’ll probably GPF on return to the caller.

3

Been that way couple of weeks ago. So, first of all, if you are using clarion composed dll in c# application, you MUST add pascal attribute to your exported dlls, procedures…
So, your procedure looks like: ```
AtualizaEstoqueNovo_Teste PROCEDURE (bstring pr),pascal. In that case you avoid to use exported flags: @FSB.
One more thing. If this is hand-coded project that you try to use in c# application? I also try this and neve succeeded. So better use application generator to create your procedures.

1 Like
4

And just one thing, your import code is:

[DllImport("C:\\Tests\\48\\prog\\ss007.dll"

but, it is much better, or mandatory, to use like [DllImport(@"C:\\Tests\\48\\prog\\ss007.dll" because you must point to the path where your dll is
5

… and third, as Carl wrote, if you are using string parameter, on clarion side that MUST be bstring.
On C# side you are declaring you clarion proc as:

const UnmanagedType MYSTRING1 = UnmanagedType.BStr; // marshaled bstring
[DllImport(V, EntryPoint = " ATUALIZAESTOQUENOVO_TESTE ")] // importing your dll with pascal entry point
static extern void ATUALIZAESTOQUENOVO_TESTE([MarshalAs(MYSTRING1)] string MYSTRING1);
and now, calling looks like:
public void TestClarion()
{
string passedstring = "Test to pass to clarion "; // string with value that you will pass to clarion
ATUALIZAESTOQUENOVO_TESTE(passedstring);
}

6

Didn’t knew that I had to add the PASCAL attribute, I`m gonna try that.

7

Thank you for all the answers, I’m gonna try again and see if it works now. I`ll be back latter to let you know if it worked.

8

this works perfectly, I must thanks to Graham Dawson who explain it to me.
For parameters other than string/bstring, all is simplier.

9

There are a lot of resources here on ClarionHub about working with C#/.net.
Search these out and review the topics.
https://clarionhub.com/search?q=.net

10 
const UnmanagedType MYSTRING1 = UnmanagedType.BStr; // marshaled bstring

[DllImport(@"C:\\Test\\48\\prog\\ss007.dll", EntryPoint = "ATUALIZAESTOQUENOVO_TESTE")]
public static extern void ATUALIZAESTOQUENOVO_TESTE([MarshalAs(MYSTRING1)] string MYSTRING1);

Using it this way worked perfectlly, thanks

2 Likes
11

… also, if you wish to return value from clarion to c#, use:

[DllImport(@"C:\\Test\\48\\prog\\ss007.dll", EntryPoint = "ATUALIZAESTOQUENOVO_TESTE")]
 [return: MarshalAs(MYSTRING1)] // mandatory
public static extern string ATUALIZAESTOQUENOVO_TESTE([MarshalAs(MYSTRING1)] string MYSTRING1); // this is function (string), not void anymore
and in code, like in clarion:
somestring =  ATUALIZAESTOQUENOVO_TESTE(yourstringparameter);
Of course, return parameter in clarion is bstring, so your declaration of clarion function would looks like;
AtualizaEstoqueNovo_Teste PROCEDURE (bstring pr),bstring,pascal
2 Likes
12

“.Net” works but is a bit small. Searching for “MarshalAs” or “DllImport” finds these results:

1 Like
13

Olá
Estou procurando muito algo parecido para executar um porcedimento do Clarion pelo C#.
Fiz varios testes porem sem nenhum resultado.
Vc teria algum exemplo para compartilhar ?

Desde já agradeço!

Google Translate - Portuguese detected

Hello
I’m really looking for something similar to run a Clarion procedure from C#.
I did several tests but without any result.
Do you have any examples to share?

Thank you very much in advance!

14

If I understood well, you need some help with clarion and c#?
Here is one small example, in zip file, the password for zip is: 1234.
In zip is clarion sample, and c# s
clarionandcsharp.zip (9.1 MB)
ample.

1 Like
17

Thank you very much!
I will study the code.