C - Pass by reference multidimensional array with known size

Question

In main:

char *myData[500][9]; //dynamic rows??
char **tableData[500]={NULL};         //dynamic rows??
int r;

newCallBack(db, &myData, &tableData, &r);

and passing into function by:

void newCallBack(sqlite3 *db, char** mdat, char*** tdat, int* r )
{

Doesn't seem to like this? Any suggestions? Lots of examples online when you don't know the size, trying them out right now....

Thanks.

Answer 1

If you were to rewrite this as such:

#define NUM_ROWS 500;
#define NUM_COLS 9;

char **myData  = NULL;
char  *tableData = NULL;
int    i;
int    r;

myData = malloc(sizeof(char *) * NUM_ROWS);
if (!myData)
    return; /*bad return from malloc*/

tableData = malloc(sizeof(char) * NUM_ROWS);
if (!tableData)
    return; /*bad return from malloc*/

for (i = 0; i < NUM_ROWS; i++)
{
    myData[i] = malloc(sizeof(char) * NUM_COLS);
    if (!myData[i])
        return;  /*bad return from malloc*/
}

You would then call newCallBack() like this if you just wanted access to the data (myData, tableData, and r):

/*prototype*/
void newCallBack(sqlite3 *db, char** mdat, char* tdat, int r);

/*call*/
newCallBack(db, myData, tableData, r);

Or this if you want to be able to modify what the vars myData and tableData point to and the value of r:

/*prototype*/
void newCallBack(sqlite3 *db, char ***mdat, char **tdat, int *r);

/*call*/
newCallBack(db, &myData, &tableData, &r);