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DBM(3)			 BSD Library Functions Manual			DBM(3)

NAME
     dbm_clearerr, dbm_close, dbm_delete, dbm_dirfno, dbm_error, dbm_fetch,
     dbm_firstkey, dbm_nextkey,	dbm_open, dbm_store -- database	access func-
     tions

SYNOPSIS
     #include <fcntl.h>
     #include <ndbm.h>

     DBM *
     dbm_open(const char *base,	int flags, int mode);

     void
     dbm_close(DBM *db);

     int
     dbm_store(DBM *db,	datum key, datum data, int flags);

     datum
     dbm_fetch(DBM *db,	datum key);

     int
     dbm_delete(DBM *db, datum key);

     datum
     dbm_firstkey(DBM *db);

     datum
     dbm_nextkey(DBM *db);

     int
     dbm_error(DBM *db);

     int
     dbm_clearerr(DBM *db);

     int
     dbm_dirfno(DBM *db);

DESCRIPTION
     Database access functions.	 These functions are implemented using
     dbopen(3) with a hash(3) database.

     datum is declared in <ndbm.h>:

     typedef struct {
	     char *dptr;
	     int dsize;
     } datum;

     The dbm_open(base,	flags, mode) function opens or creates a database.
     The base argument is the basename of the file containing the database;
     the actual	database has a .db suffix.  I.e., if base is
     "/home/me/mystuff"	then the actual	database is in the file
     /home/me/mystuff.db.  The flags and mode arguments	are passed to open(2).
     (O_RDWR | O_CREAT)	is a typical value for flags; 0660 is a	typical	value
     for mode.	O_WRONLY is not	allowed	in flags.  The pointer returned	by
     dbm_open()	identifies the database	and is the db argument to the other
     functions.	 The dbm_open()	function returns NULL and sets errno if	there
     were any errors.

     The dbm_close(db) function	closes the database.

     The dbm_store(db, key, data, flags) function inserts or replaces an entry
     in	the database.  The flags argument is either DBM_INSERT or DBM_REPLACE.
     If	flags is DBM_INSERT and	the database already contains an entry for
     key, that entry is	not replaced.  Otherwise the entry is replaced or in-
     serted.  The dbm_store() function normally	returns	zero but returns 1 if
     the entry could not be inserted (because flags is DBM_INSERT, and an en-
     try with key already exists) or returns -1	and sets errno if there	were
     any errors.

     The dbm_fetch(db, key) function returns NULL or the data corresponding to
     key.

     The dbm_delete(db,	key) function deletes the entry	for key.  The
     dbm_delete() function normally returns zero but returns 1 if there	was no
     entry with	key in the database or returns -1 and sets errno if there were
     any errors.

     The dbm_firstkey(db) function returns the first key in the	database.  The
     dbm_nextkey(db) function returns subsequent keys.	The db_firstkey()
     function must be called before dbm_nextkey().  The	order in which keys
     are returned is unspecified and may appear	random.	 The dbm_nextkey()
     function returns NULL after all keys have been returned.

     The dbm_error(db) function	returns	the errno value	of the most recent er-
     ror.  The dbm_clearerr(db)	function resets	this value to 0	and returns 0.

     The dbm_dirfno(db)	function returns the file descriptor to	the database.

SEE ALSO
     open(2), dbopen(3), hash(3)

STANDARDS
     These functions (except dbm_dirfno()) are included	in the Version 2 of
     the Single	UNIX Specification ("SUSv2").

BSD				April 16, 2006				   BSD
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | STANDARDS

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