implementing a QSYS snap-in, and the default QSYS search path

There's an undocumented (or poorly documented) environment variable that you can set; IP_IPX_PATH

This variable can contain a comma separated list of paths to .ipx files, and the .ipx files can be created with ip-make-ipx.exe

Look at the source code associated with this tutorial

http://www.ovro.caltech.edu/~dwh/correlator/pdf/esc-104paper_hawkins.pdf

The script

ESC-104Code_Hawkins\dsp_tutorial\vhdl\boards\de0_nano\cyclone4\dsp_tutorial\scripts\synth.tcl

shows how to create this path dynamically using Tcl.

There's bound to be other alternatives, but this might give you an idea ...

Cheers,

Dave