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Accessing user shared memory from C
Question: How do I access Sys.Fdata memory from a bgcplc? What I specifically need to do is to read in data from an array in Sys.fdata memory. I don't want to declare pointers to every block in the array, just to increment a pointer.

Here is how to do it: (be careful if you decide to use double, since it is 64bit and it will use up the user shared memory in batches of 2 32bit locations at a time)

#include <RtGpShm.h>
#include <stdio.h>
#include <dlfcn.h>
void user_plcc()

      float *myfloat;
      myfloat = (float*)pushm; // setting the address from void pointer pushm casted as float pointer
      *myfloat=5.5; // equivalent of sys.fdata[0] – you can also write it as myfloat[0]=5.5;
      myfloat[3]=3.141592;    // equivalent of sys.fdata[3]

Sina Sattari
Hardware Engineering Manager
Delta Tau Data Systems, Inc.

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