Re: Returning character variables from C to RPG

It has nothing to do with either C or RPG, you have to know the
concept of Aotumatic Memery vs Static Memery!!

In you C, change

char* check_bit;
to
static char* check_bit;

will fix your problem. Try it.

Ge An

Krish Thirumalai wrote:

> Writing my first program in C in the ILE environment and I am really puzzled.
>
> I have the following RPG program that is calling a C function, but all i get 
> back is a Null each time. If i put it in debug mode i can see that the value 
> of chkdigit is correct, but then, when i get it back in my RPG, the value is 
> NULL.
>
> Can someone point out what i am doing wrong ?
>
> RPG program
>
> D Pr_ChkDigit PR * ExtProc('Pr_ChkDigit') D * Options(*string) value
> D Wrk_Str s 36A D Wrk_Null s 1A Inz(X'00') D Wrk_ChkDigit s 1A D Ptr_ChkDigit 
> s * INZ(%ADDR(Wrk_ChkDigit))
> /Free Wrk_Str = '70500607050AEI02x' + Wrk_Null; Ptr_ChkDigit = 
> Pr_ChkDigit(%Addr(Wrk_Str)); Dsply Wrk_ChkDigit; *InLr = *on; /End-Free
> C service program
>
> // Mod 36 Check bit calculator char* Pr_ChkDigit(char *str) {
> char chkdigit; char* check_bit;
> //Calcuations // Get checkbit from the Mapping Matrix 
> chkdigit=reverse_map(c1,c2) ; *check_bit = chkdigit; return check_bit;
> }
>
>
>  
>