Extern "C" in C and C++

SystemVerilog
,
1

Hi,

I want to use sub task with extern “C” in C or C++ code.
When I call a task in C++, it works well.


extern "C" void check(); // at C++ code
main(){
  check();
}

However, it looks dosen’t work in C code.
How to call sub task check() in Code?


//extern "C" void check();

main(){
  check();
}
2

In reply to uvmbee:


 Here is a sample code :

module hello_kitty;
  
   export "DPI-C" task random_data;
 
   import "DPI-C" context task read_from_c();
  
  task read();
    read_from_c();
  endtask
  
  task random_data(output int rdata,int wdata);
    rdata = $urandom_range(0,20);
    wdata = $urandom_range(0,10);
    $display ("Randomized rdata = %d and wdata = %d",rdata,wdata);
  endtask
  
  
endmodule :hello_kitty


module test;
  hello_kitty h1();
  
  initial repeat(10)
	begin
	   h1.read;
  	    // this works too - no wrapper needed
           #500; // read every 
	end
  
endmodule


#include "stdio.h"
#include "svdpi.h"


extern int random_data(int*, int*);

int read_from_c(void)
{
  int hi;
  int hello;
  int x;
  x = random_data(&hi,&hello);
  printf ("rdata = %d, wdata = %d \n",hi,hello);
  return 0;
  
  
}
3

In reply to rag123:
Thank you rag123,

What I did upon your example was adding include “svdpi.h” in my C code.
But it returns compile error as below.


gcc -w  -pipe -m32 -O -I/apps/vcsmx/vcs/S-2021.09/include    -c ../test.c
../test.c:4:8: error: expected identifier or '(' before string constant
 extern "C" void check();
        ^
make[1]: *** [test.o] Error 1
4

In reply to uvmbee:

works for me :) you have to post your code or give the link to the code.