[Discuss-gnuradio] cmake max version test?

[Michael Dickens]

It turns out that gr-qtgui isn't compatible with the QWT 6 API.  It works with 
QWT 5.2.1 and 5.1.2; I don't know about 5.0.2 or earlier.

Does anyone know if there a (simple) way in CMake to check that the library is 
-not- of a specific version?  For example:

find_package(Qwt "< 6")

where the "< 6" is used for version checking.  We could use 'find_package(Qwt 
5)' but then I don't know if the gr-qtgui is compatible with QWT 4.2.0 (and, 
I'm not inclined to do so given that that version dates to 2004).  QWT does not 
install a PKGCONFIG, not a "qwt-config" type of script; as far as I can tell, 
the only way to verify its version is by either checking that of the installed 
library or its headers (and, for cross-OS compatibility I'd guess the latter).

I'd love to see an updated gr-qtgui, but the QWT 6 API is quite different than 
that from 5 & there are a number of changes that would be required in the GR 
code -- so, probably not anytime soon given the number of changes that would be 
required.

Anyway, wondering if anyone knows of a simple solution.  Thanks! - MLD