[Boost-build] differentiating between bjam clean and bjam -a

From: Patrick Tan (pxt_at_[hidden])
Date: 2005-12-18 23:56:00

I want to perform different pre build actions depending on whether it is 
"bjam clean", "bjam -a" or "bjam" inside my Jamfile.

For example I would like to do something like this in my Jamfile:

if (bjam clean)
{
    SHELL "rm myVersioningFile.h" ;
}
else if (bjam -a)
{
    SHELL "rm myVersioningFile.h" ;
    SHELL "prebuild.sh > myVersioningFile.h" ;
}

Would anyone know how I can achieve the above pseudo code in a Jamfile.

Thanks