dbm_firstkey() -- read first key in database

SYNOPSIS

#include <ndbm.h>

datum dbm_firstkey(DBM *db);

DESCRIPTION

The dbm_firstkey() function returns the first key in the database specified by db.

A datum consists of at least two members, dptr and dsize. The dptr member points to an object that is dsize bytes in length. Arbitrary binary data, as well as character strings, may be stored in the object pointed to by dptr.

This function can be combined with dbm_nextkey() to traverse the database, using code such as:

for (key = dbm_firstkey(db);
	key.dptr != NULL;
	key = dbm_nextkey(db))
{
}

PARAMETERS

db: Points to database where the key is fetched from. This must be a pointer returned by a prior call to dbm_open().

RETURN VALUES

The dbm_firstkey() function returns a key datum. When the end of the database is reached, the dptr member of the key is a null pointer. If an error is detected, the dptr member of the key is a null pointer, and the error condition of the database is set.