Hi,

I've seen that there are more posts about the following, but never with a conclusive answer :

We have

• created an external library with a new function block

• added code to the .c file

• compiled it using Visual C++

• created a new program in CoDeSys, and used the custom function block, without problems.

So far everything works fine.

However, when the C code has dependencies, such as when I add

\#include <math.h>

and I use for example a sin() function, I get the following error:

Error 3162: Could not resolve reference in Library 'C:\DOCUMENTS AND SETTINGS\WIM\MIJN DOCUMENTEN\CODESYSTEST11\EXTTEST.OBJ' (Symbol '_sin', Class 'EXTERNAL', Type 'REL32')

Is there anyone who could give some advice on how we could solve this?

For a project in the near future we're currently studying our different options, and CoDeSys seems very attractive so far, however in this project we really rely on external code.

Thank you very much.

Wim

In "C_in_32Bit_E.pdf" I read:

Zitat:
If you want to use any ANSI C standard library functions you must activate the following
selection in the project settings:
Build / Settings / C/C++ / Category: Optimizations : Customize: Generate Instrinsic
Functions
In this way the simplest ANSI C library functions are implemented in-line (strcpy(),...).
Otherwise no libraries may be used.

Does that mean that I cannot even use <math.h> functions such as sin() in my C code? Or am I missing the point and is there another way to do it?</math.h>

Thank you!

Wim

Hi Wim;
I had this same problem for long time and i had solved it.Normally it is not possible to compile math.h in SPS environment. But i have found a solution. U should write ur own function in Visual c++ like all math.h function.( Sin COS fabs) then it is possible and i have done it. My "Self math.H" has a accuracy almost 0.0001 to 0.005 comparing math.h.

it is little bit hard at the beginning. Anyway I hope, u understand what i have said.

Best Regards,
Asif

math.h is has different data types so you will have to rewrtite your own or make the datatypes available, or in math change the functions used.
However if you need better sin function another way is to have it calculated with the root function.
You could also look into w www.oscat.de w he has several functions available.