Checking the Status Vector for Errors
Go Up to Using Information in the Status Vector
API functions that return information in the status vector are declared in ibase.h as returning an ISC_STATUS pointer. For example, the function prototype for isc_prepare_transaction() is declared as:
ISC_STATUS ISC_EXPORT isc_prepare_transaction(ISC_STATUS ISC_FAR *,
isc_tr_handle ISC_FAR *);
To check the status vector for error conditions after the execution of a function, examine the first element of the status vector to see if it is set to 1, and if so, examine the second element to see if it is not 0. A nonzero value in the second element indicates an error condition. The following C code fragment illustrates how to check the status vector for an error condition:
#include <ibase.h>
. . .
ISC_STATUS status_vector[20];
. . .
/* Assume an API call returning status information is called here. */
if (status_vector[0] == 1 && status_vector[1] > 0) {
/* Handle error condition here. */
}
If an error condition is detected, you can use API functions in an error-handling routine to display error messages, capture the error messages in a buffer, or parse the status vector for particular error codes.
Display or capture of error messages is only one part of an error-handling routine. Usually, these routines also roll back transactions, and sometimes they can retry failed operations.