[HACKERS] Passing parameters to a C function

[Rodrigo Sakai]

    Hello,

 

   I have a question about passing parameters to a C function.  Imagine the
example by PostgreSQL:

 

PG_FUNCTION_INFO_V1(complex_add);

 

Datum

complex_add(PG_FUNCTION_ARGS)

{

      Complex    *a = (Complex *) PG_GETARG_POINTER(0);

      Complex    *b = (Complex *) PG_GETARG_POINTER(1);

      Complex    *result;

 

      result = (Complex *) palloc(sizeof(Complex));

      result->x = a->x + b->x;

      result->y = a->y + b->y;

      PG_RETURN_POINTER(result);

}

 

 So, in the same .C file I have to write another function that calls this
one, for example: 

 

void

test_main()

{

    Complex *a;

    Complex *b;

 

    a = complex_in("(4.01, 3.77 )");

    printf("a = %s\n", complex_out(a));

 

    b = complex_in("(1.0,2.0)");

    printf("b = %s\n", complex_out(b));

 

    printf("a +  b = %s\n", complex_out(complex_add(a,b)));

}

 

But using version 1 calling convention it won't work! So, how can I pass the
'a' and 'b' variables in complex_add(?, ?)?

 

Thanks in advance!