Transaction Handle Declaration Requirements

From InterBase

A transaction handle must be declared and initialized to zero before use. The following code illustrates how to declare and initialize a transaction handle:

#include <ibase.h>
. . .
/* Declare a transaction handle. */
isc_tr_handle tr1;
. . .
/* Initialize the handle. */
tr1 = 0L;

For more information about declaring, initializing, and using transaction handles, see Working with Transactions.