isnull
if (!(ret_val = isnull(param, value))) {
if (!(ret_val = isnull(param, value))) {
static int isnull(char *param, char *pt);
if (!(ret_val = isnull(param, value))) {
if (!(ret_val = isnull(param, value))) {
int i, j, n, c, isnull;
isnull = arg==0;
if( isnull ) arg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
n += i + 1 + ((!isnull && xtype==etSQLESCAPE2) ? 2 : 0);
if( !isnull && xtype==etSQLESCAPE2 ) bufpt[j++] = '\'';
if( !isnull && xtype==etSQLESCAPE2 ) bufpt[j++] = '\'';