I'm sharing this code as an example of how two different DPI calls (calls to same function in two different parts of the hierarchy) can both manipulate a C global variable.<br>

----file: my_dpi.c----
#include "stdio.h"
#include "svdpi.h"

// any function or variable declared 'static' - which is outside the
// scope of any DPI function, is a global func/var.
static int my_global_int = 4;

// FYI - VPI function io_printf() will print to ncsim.log file

// This function can be called from any Verilog Hierarchy
// and manipulate my_global_in

int c_func () {  
  my_global_int++;  // increment the global variable via DPI call
  io_printf("C: Function Calling HDL scope is %s \n", svGetNameFromScope(svGetScope() ) );

  io_printf("C: increment my_global_in to %d \n", my_global_int);
  return my_global_int;
}
---------------
----file: test_dut.sv
// this example developed to test if DPI can manipulate 
// a C global variable from different hierarchies

module dut ();

import "DPI-C" context c_func = function int sv_func ();
int b;

initial
 begin
 b = sv_func();
 $display("Verilog: %m %d", b);
 end

endmodule
// ------------------------

module test();
import "DPI-C" context c_func = function int sv_func ();
int b;

initial
 begin
 b = sv_func();
 $display("Verilog: %m %d", b);
 end

endmodule
// ------------------------

module top();

test U1();
dut  U2();

endmodule
----------------

ncsim: 05.83-s006: (c) Copyright 1995-2007 Cadence Design Systems, Inc.
ncsim> run
C: Function Calling HDL scope is top.U1 
C: increment my_global_in to 5 
Verilog: top.U1           5
C: Function Calling HDL scope is top.U2 
C: increment my_global_in to 6 
Verilog: top.U2           6
ncsim: *W,RNQUIE: Simulation is complete.
ncsim> exit

-------script: -------------

ncvlog -sv -linedebug test_dut.sv
ncelab top

gcc -m32 -fPIC -g -shared -o my_dpi.so my_dpi.c  -I/`ncroot`/tools/inca/include

ncsim top -sv_lib ./my_dpi.so