Entering code within the C-block or C++-block (deprecated)

How to enter the C-code or C++-code in your →blocks and use them within →ST:

1. As preparation, set the correct build configuration: context menu of the project, select Build Configurations, Set Active and the command for the corresponding platform
   Without this preparation you will not be able to use the logi.CAD 3 functions to navigate within the libraries to be used.

2. Double-click the file LCfu___name.c or LCfu___name.cpp displayed in the project explorer.
   This file has automatically been created by logi.CAD 3, when you have created the interface for the C-block or the C++-block.

3. In the opened file, enter the required C-code or C++-code.
   Use a This Pointer for accessing variables as well as in-/outputs (for function blocks) or outputs (for functions) that you have declared for the interface. Enter all names in upper-case letters.
   For functions, the access to inputs is done without using a This Pointer.

   Example for accessing input/output of the function block

   #define V(VAR) (LC_this->LC_VD_##VAR) /* C-macro for a simplified access to parameter */

   /* ... */

   V(OUT) = V(IN1) + V(IN2); /* your C-code within the C-file for the function block */
   Example for accessing input/output of the function

   #define V(VAR) (LC_this->LC_VD_##VAR) /* C-macro for a simplified access to parameter */

   /* ... */

   V(OUT) = LC_VD_IN1 + LC_VD_IN2; /* your C-code within the C-file for the function */

   V(MYCFUN) = LC_VD_IN1 + 1;

   Restriction for C-blocks

   • Do not enter any comments in C++ style for C-block. See the FAQ-article "May I comment my C-code?" for details.

   • Use POU-unique names (when possible, project- and POU-unique) for all C-identifiers that are available in a global namespace. See "The dos and don'ts when working, When creating blocks with C-code" for details.

4. Save the file with your C-code or C++-code.

5. Repeat the steps for each file in which you want to enter C-code or C++-code.

6. Use the function blocks and functions within your application (e.g. with the →program that has been declared within an ST-object without {extern_c} or {extern_cxx}):

   1. Required only for function blocks: Declare the required →function block instances. The necessary syntax is listed under: "Declaration of function block instances in ST"

   2. Required for function blocks and functions: Enter the calls of the blocks. The necessary syntax is listed under: "Calls in ST"

7. Save the ST-object with your application.

If you load the application onto the PLC now, the defined code of the C-block or C++-block is included.