Example: Shared Memory

Two applications are used for the demonstration. Each one of the applications has to run on a separate runtime system on the same target device. Then both of these runtime system processes communicate by means of shared memory. The first application creates a shared memory and writes some values to the memory, and the second application reads the memory.

Write_App: The application creates a shared memory object and writes some strings to memory.

Read_App: The application tries to open the shared memory and read the data in two different ways. In the first case, a data string of a specific size is read. In the second case, the pointer to the first element is fetched and incremented until the "End of Text" character is reached. After that, the memory is deleted.

You need to download both applications to the target device, either by Multiple Download or a separate download of each application.

To start a second CODESYS runtime system, open the Windows Start menu. Go to CODESYS Control Win and open the CODESYS Control Win. Now this is now running next to "CODESYS Control Win Sys Tray".