Re: Calling an RPG procedure with optional parameters from C code

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

RPG (by default) passes parameters by reference.  C (by default) passes
parameters by value.   To pass a parameter by reference from C, you put a
pointer on the prototype, and you pass the address of a variable to that
pointer.

RPG's *OMIT is equivalent to passing a NULL pointer.

So, from C, you simply pass NULL instead of a variable.  For example:


prototype:

void procname(char *param1, char *param2, char *param3, char *param4);

code:

   char val1[50], val2[50], val3[30], val4[50];

// set the "val" variables to useful values here

   procname( val1, NULL, val3, val4);

   - or -

   procname( NULL, val2, val3, val4);


etc, etc.