Accelerate Interbase Dll call

Hi

 I use Dlls in my application with InterBase.

Every function call in my dll creates one connexion : and it's a long
time for each call. My Dlls don't stay in mmory ( Not use of extern
command) cause I call the API loadlibrary function.

How to speed every call ? Can I keep the Tsession and use it in dll
functions ? how to do it ? With Tsession  parameter ?

thansk a lot

 Mike