The recommended way to backup a database is to use the BACKUP DATABASE statement.
The db_backup function provides another way to perform an online backup in embedded SQL applications. The SAP Sybase IQ utility also makes use of this function.
You can also interface directly to the SAP Sybase IQ Backup utility using the Database Tools DBBackup function.
You should only undertake to write a program using the db_backup function if your backup requirements are not satisfied by the any of the other backup methods.