As of version 1.22,
GDBM supports databases in
two formats: standard and extended. The standard format
is used most often. The extended database format is used to
provide additional crash resistance (see Crash Tolerance).
Depending on the value of the flags parameter in a call to
gdbm_open (see GDBM_NUMSYNC), a database can be
created in either format.
The format of an existing database can be changed using the
Changes the format of the database file dbf. Allowed values for flag are:
Convert database to the standard format.
Convert database to the extended numsync format (see Numsync).
On success, the function returns 0. In this case, it should be
followed by a call to
gdbm_sync (see Sync) or
gdbm_close (see Close) to ensure the changes are written to
On error, returns -1 and sets the
If the database is already in the requested format, the function returns success (0) without doing anything.