Accessing a custom FileSystem (as in Mysql "Custom Engine")

[Scara Maccai <m_lists@xxxxxxxx>]

Hi,

I have a custom "database" (a very fast select/slow insert db) written 
in c/c++.
I can access it with mysql writing a "Custom Engine". That is pretty 
cool because now all my "custom db" tables can be joined with tables in 
mysql's format.
I only need read access to my custom table format db. Would read access 
be possible with the "C-Language Functions - Returning Sets" API? I 
would like to read my custom tables and join them with postgres tables...