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Berkeley DB: DB->cursor
DB->cursor
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#include <db.h>
int
DB->cursor(DB *db,
DB_TXN *txnid, DBC **cursorp, u_int32_t flags);
Description
The DB->cursor function
creates a cursor and copies a pointer to it into the memory to which
cursorp refers.
If the operation is to be transaction-protected, the txnid
parameter is a transaction handle returned from txn_begin;
otherwise, NULL.
To transaction-protect cursor operations, cursors must be opened and
closed within the context of a transaction, and the txnid
parameter specifies the transaction context in which the cursor may be
used.
The flags value must be set to 0 or by bitwise inclusively OR'ing together one or
more of the following values:
- DB_DIRTY_READ
- All read operations performed by the cursor may return modified but not
yet committed data. Silently ignored if the DB_DIRTY_READ flag
was not specified when the underlying database was opened.
- DB_WRITECURSOR
- Specify that the cursor will be used to update the database. The
underlying database environment must have been opened using the
DB_INIT_CDB flag.
The DB->cursor function returns a non-zero error value on failure and 0 on success.
Errors
The DB->cursor function may fail and return a non-zero error for the following conditions:
- EINVAL
- An invalid flag value or parameter was specified.
The DB->cursor function may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions.
If a catastrophic error has occurred, the DB->cursor function may fail and return
DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail
in the same way.
See Also
db_create,
DB->associate,
DB->close,
DB->cursor,
DB->del,
DB->err, DB->errx
DB->fd,
DB->get,
DB->pget,
DB->get_byteswapped,
DB->get_type,
DB->join,
DB->key_range,
DB->open,
DB->put,
DB->remove,
DB->rename,
DB->set_alloc,
DB->set_append_recno,
DB->set_bt_compare,
DB->set_bt_minkey,
DB->set_bt_prefix,
DB->set_cachesize,
DB->set_dup_compare,
DB->set_errcall,
DB->set_errfile,
DB->set_errpfx,
DB->set_feedback,
DB->set_flags,
DB->set_h_ffactor,
DB->set_h_hash,
DB->set_h_nelem,
DB->set_lorder,
DB->set_pagesize,
DB->set_paniccall,
DB->set_q_extentsize,
DB->set_re_delim,
DB->set_re_len,
DB->set_re_pad,
DB->set_re_source,
DB->stat,
DB->sync,
DB->truncate,
DB->upgrade,
and
DB->verify.
Copyright Sleepycat Software
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