[C400-L] RE: Help Calling a C program From CL

["Chris Wolcott" <cwolcott@xxxxxxxxxxxxxxxxxxxxxx>]

I find it easier to just tack on a NULL in the CL.  That way I don't
have to make the C procedure CL centric.  

DCL VAR(&NULL) TYPE(*CHAR) LEN(1) VALUE(X'00')

CHGVAR VAR(&STRING) VALUE(&STRING |< &NULL)
      -- OR --
CHGVAR VAR(&STRING) VALUE('what ever you want' |< &NULL)
      -- OR --
SOMECMD VAR('TEXT' |< &NULL)  - Assuming the command allows expressions

If you are going to go to the effort of using a C function, why pad with
NULL?  If you know the length just use this:

char c_str[max_size];

memcpy(c_str, cl_str, len);
c_str[len] = '\0';

8< - - -

If you want to return an int result to CL, you need to make a procedure
call, not a program call.  This means your CL must be CLLE.  Declare a 4
character variable named &RTNVAL and use CALLPRC PRC(C_PGM) PARAM(&PARM)
RTNVAL(%BIN(&RTNVAL)), then test %BIN(&RTNVAL) or move it to an *DEC.  I
have not tried to return a string, I don't know if the return value is
done by reference or value.

C could write EBCDIC to a DB/2 file and CL can open and read that.  You
could also use a *DTAQ or *DTAARA via an API and CL can read either of
those just also.