Connect to a database
Synopsis:
#include <qdb/qdb.h>
qdb_hdl_t *qdb_connect( const char *dbname, int flags );
Arguments:
- dbname
- The database device name (e.g., /dev/qdb/customerdb).
- flags
- Flags that determine the connection properties. This argument can be 0 (no
flags) or a combination of:
-
- QDB_CONN_DFLT_SHARE
-
Use
the default sharing policy for the database connection (as given
in the -C command-line option to QDB). Without
this flag, a private connection is forced.
- QDB_CONN_NONBLOCKING
-
If
this flag is set, qdb_statement() fails and
returns immediately (setting errno to
EBUSY) if the database file is locked. By
default, qdb_statement() waits for at least
the busy timeout period (set using qdb_setbusytimeout()) if the
database is locked, before returning with a failure result.
- Setting this flag also makes subsequent calls to
qdb_connect() nonblocking (as if the
-T command-line option were 0).
- QDB_CONN_STMT_ASYNC
-
Execute statements in asynchronous
mode. In this mode, qdb_statement() may return
before the statement has finished executing against the
database.
Library:
qdb
Description:
This function connects to the specified database and sets properties of the database
connection. When successful, the function returns a pointer to a handle for the new
connection. You need to call qdb_connect() for every database or
every concurrent access to one database. For an example of connecting to a database,
see “Connecting to a database”.
Note: Two threads can share the same database connection, provided that they coordinate
between themselves. Or, each thread can call this function to obtain its own
connection.
You should terminate all connections by calling qdb_disconnect() when you're finished using them.
Returns:
- A pointer to an opaque database connection handle (qdb_hdl_t)
- Success.
- NULL
- An error occurred (errno is set).
Classification:
QNX Neutrino
| Safety: |
|
| Interrupt handler |
No |
| Signal handler |
No |
| Thread |
Yes |