Getting oid with libpq

Hello,

I have stored some large objects (which are images) with the lo_import
function. Now I can read the images with the other functions like lo_read
within libpq. But I have one problem with the oid I have to give to this
method. Inside my program I will do a select like this

Select texture from building_face where face_id > 100;

Textures is the oid field. When I use PQgetValue() I get a complete
different value then when I do a select inside pgAdmin. How can I get the
same oid so that I can use this for reading the data of the images inside my
c++ program. Because it is not working with the oid from PQgetValue.

Best regards,

Johan de Koning