does the qt uses the gcc version in the system, or its has its own version ??

also how can i know which OpenMp API the qt4.8.1 uses ?? is it installed with it ?? i Use qt creator 2.4.1.
or
how can i know what version of OpenMP it uses, i insert some OpenMP pragma and it compiles and runs fine.
I just want to know what version it is and how can i make qt points to other version.

I would appreciated any inlighting in these matters. or place to look into.

Thank you