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 for determining parameters of the connection. This argument can be 0 (no flags) or a combination of:
-
- QDB_CONN_DFLT_SHARE
-
Use the default database connection share mode (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 asynchronously. In this mode, qdb_statement() may return
before the statement has finished executing against the database (see "Using asynchronous mode").
Description:
This function connects to the database specified by dbname and sets parameters for the database connection.
When successful, the function returns a pointer to a handle for the new connection.
You need to call this function for every database or for concurrent access to one database.
Note:
Two threads can share the same database connection, provided that they coordinate between themselves. Alternatively, each thread can call qdb_connect() and have its own connection.
You should terminate all connections by calling qdb_disconnect() when you're finished using them.
Returns:
- A valid pointer to an opaque database connection (qdb_hdl_t)
- Success.
- NULL
- An error occurred (errno is set).
Classification:
QNX Neutrino
| Safety: |
|
|---|
| Interrupt handler |
No |
| Signal handler |
No |
| Thread |
Yes |