NAME
tdb_firstkey - return the key of the first record in a tdb database
tdb_nextkey - return the key of next record in the tdb database
SYNOPSIS
#include <tdb.h>
TDB_DATA tdb_firstkey(TDB_CONTEXT *tdb);
TDB_DATA tdb_nextkey(TDB_CONTEXT *tdb, TDB_DATA prev_key);
DESCRIPTION
tdb_firstkey fetches the key of the first entry in the tdb database.
tdb_nextkey fetches the key of the entry immediately after prev_key in
the database.
The TDB_DATA structure returned by both these functions is defined as:
typedef struct {
char *dptr;
size_t dsize;
} TDB_DATA;
The order in which this traverses the database is its own internal hash
order. Do not expect the keys to be in any recognizably sorted order.
These functions are reliable even if other writers are accessing the
database (or you are replacing or deleting elements as you traverse),
except in the case of nested tdb_firstkey or tdb_nextkey calls. For
example, the following outer traversal may fail to traverse all the
elements, or may even traverse elements twice if other processes are
manipulating the database:
TDB_DATA i, j;
for (i = tdb_firstkey(tdb); i.dptr; i = tdb_nextkey(tdb, i)) {
for (j = tdb_firstkey(tdb); j.dptr; j = tdb_nextkey(tdb, j)) {
...
}
}
If such behaviour is desired, use tdb_traverse instead.
RETURN VALUE
If the call succeeds, then a TDB_DATA structure is returned with the
dptr structure filled in. If the call fails or you have reached the end
of the database then dptr will be set to NULL.
NOTE: The caller is responsible for freeing the data pointed to by dptr
AUTHORS
Software: Andrew Tridgell <tridge@linuxcare.com> and Luke Kenneth
Casson Leighton Man page: Ben Woodard <ben@valinux.com>
SEE ALSO
gdbm(3), tdb(3)