Проект OpenNet: MAN dbm_firstkey (3) Библиотечные вызовы (FreeBSD и Linux)

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dbm_firstkey (3)

>> dbm_firstkey (3) ( FreeBSD man: Библиотечные вызовы )

dbm_firstkey (3) ( POSIX man: Библиотечные вызовы )

BSD mandoc

NAME



dbm_clearerr

 
dbm_close

 
dbm_delete

 
dbm_dirfno

 
dbm_error

 
dbm_fetch

 
dbm_firstkey

 
dbm_nextkey

 
dbm_open

 
dbm_store

 - database access functions

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.

Vt datum is declared in In ndbm.h :

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

The dbm_open (base flags mode);
function opens or creates a database. The Fa base argument is the basename of the file containing the database; the actual database has a .db suffix. I.e., if Fa base is Qq Li /home/me/mystuff then the actual database is in the file /home/me/mystuff.db The Fa flags and Fa mode arguments are passed to open(2). (O_RDWR | O_CREAT ) is a typical value for Fa flags ; 0660 is a typical value for Fa mode . O_WRONLY is not allowed in Fa flags . The pointer returned by dbm_open ();
identifies the database and is the Fa 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 Fa flags argument is either DBM_INSERT or DBM_REPLACE If Fa flags is DBM_INSERT and the database already contains an entry for Fa key , that entry is not replaced. Otherwise the entry is replaced or inserted. The dbm_store ();
function normally returns zero but returns 1 if the entry could not be inserted (because Fa flags is DBM_INSERT and an entry with Fa key already exists) or returns -1 and sets errno if there were any errors.

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

The dbm_delete (db key);
function deletes the entry for Fa key . The dbm_delete ();
function normally returns zero but returns 1 if there was no entry with Fa 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 error. 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.

STANDARDS

These functions (except dbm_dirfno ());
are included in the St -susv2 .

Партнёры:

Хостинг:

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