Thread: "Different levels of indirection" compilation error

In converting an MS C (v6) program from Scalable SQL to the Btrieve API (BTRV function), I need to understand the intricacies of pointers in order to resolve a "different levels of indirection" compilation error.

The original program declared cursors and hence read in several records at a go (using xNew and xFetch). Relevant code, I hope, below...

Code:

#define N_FETCH  20
#define NIBBLE   0x000F /* binary representation 0000000000001111  */
                        /* This half-byte is used to mask off all but the
                           four bits of interest in each conversion step.   */
#define BYTE     0x00FF  /* binary representation 0000000011111111   */

struct crdRec
{   int  Recordlen;
     char  CrCustnum  [6];
<snip>
     char CrFxfwddelex [7];
     char CrSgnfxfdlex [1];
};
struct i1bRec
{   int  Recordlen;
     char  Custnum  [6];
<snip>
     char Sgnfxfdlex [1];
     char Fxfwddelex [14];
};
struct  crdRec  crdVRec  [N_FETCH];
struct  i1bRec   i1bVRec  [N_FETCH];
int rind;
char  hexbuf [5];
char *inPtr, *outPtr;
char hextab[] = { '0', '1', <snip> 'F' };
char *byte2hex (unsigned char, char *);

That is most of the relevant declarations. Here is some code.

Code:

/* code to select cursor of data*/
status = xFetch (cursorID1, &bufLen, opt, &recCount, 
                              &rejCount, (char *) crdVRec);
if (status == 0 || status == 9)
{
/* total number of records selected  */
  t_recCount += recCount;

  for (rind = 0; rind < recCount; rind++)
  {
    i1bVRec[rind].Recordlen = sizeof(struct i1bRec) -2 ;
    strncpy (i1bVRec[rind].Custnum, crdVRec[rind].CrCustnum,  6);
<snip>
/* convert packed data field  */       
   inPtr = (char *) &crdVRec[rind].CrFxfwddelex ;
   outPtr = (char *) &i1bVRec[rind].Fxfwddelex ;

   for (i = 0;  i < 7 ; ++i)
     {
       strcpy (outPtr, byte2hex (*inPtr++, hexbuf));
       outPtr  += 2;
      }

It is on the strcpy, on my converted version, where it gives the compilation error. I haven't tried compiling this original code yet; I'll do that shortly, it may not compile itself for all I know. I've had that happen before!

For info, the byte2hex function:

Code:

/* =========================  byte2hex () ================ */
/*   Convert a byte to a string representation of its hexadecimal value     */
/*   The function byte2hex() , converts a byte-sized(8-byt) quantity to     */
/*   hexadecimal.                                                           */
/*   The hextab array is a conversion lookup table. It uses a number in     */
/*   the range of 0 through 15 as an index into the table, where the        */
/*   corresponding character constant (number or letter) is found.          */
/* =================================================== */

char *byte2hex (data, buf)
unsigned char data;
char *buf;
{
   char *cp;
   unsigned int d;


   d = data & BYTE;  /* turn off the 4 high order bits */
   cp = buf;         /* assign pointer to output buffer */

   /* Right-shift operations are used to pull the needed bits into the
      correct position for convertion to a hexadecimal digit.   */
   /* move 1st 4 low order bits to right and turn off all other bits */
   *cp++ = hextab [(d >> 4) & NIBBLE];

   /* turn off last 4 low order bits */
   *cp++ = hextab [d & NIBBLE];

   *cp = '\0';
   return (buf);
}
/* End of byte2hex */

Now for my converted version, using the Btrieve API. I am not using a cursor, hence only reading one record at a time. I am not using crdVRec and i1bVRec,
but am doing the following:

Code:

struct  crdRec  CRD_REC_BUF,  *pj;
struct  i1bRec   OUT_BUF,        *po;

pj = &CRD_REC_BUF;
po = &OUT_BUF;

Then the similar point in the code as before is

Code:

memcpy 9po->Custnum, pj->CrCustnum, 6);
<snip>
/* convert packed data field  */
inPtr = (char *) pj->CrFxfwddelex;
outPtr = (char *) po->Fxfwddelex;
for (i = 0; i < 7;  ++1)
{
  strcpy (outPtr, byte2hex (*inPtr++, hexbuf));
  outPtr  += 2;
}

At first I thought the different levels of indirection seemed clear, in that there is a pointer and a character array (inPtr and hexbuf), but then thought further that the compiler should be looking at the output from the function byte2hex (which is a pointer) so it should be ok? Obviously, I am confused! :?

Actual messages from compiler as follows:
warning C4047: 'argument' : different levels of indirection
warning C4024: 'strcpy' : different types : parameter 2

Any help gratefully received.

Ancient!

Yep, it was missing a prototype after all that. Thanks.