Multithreading
The Firebird ODBC driver provides two levels of thread protection.
Via the sharing of either environment or connection handles.
If the driver is built using the following define:
#define DRIVER_LOCKED_LEVEL DRIVER_LOCKED_LEVEL_NONE
then the driver is built without multi-threading support. This provides for fastest
performance, however responsibility for threading control is transferred to the Firebird
client library.
Default: The driver is built using the following define:
#define DRIVER_LOCKED_LEVEL DRIVER_LOCKED_LEVEL_CONNECT
then a single connection can share multiple local threads.
If the driver is built using the following define:
#define DRIVER_LOCKED_LEVEL DRIVER_LOCKED_LEVEL_ENV
then a single environment handle can be shared by multiple local threads.