difference between lapacke and lapack

I wonder what is the difference between LAPACKE and LAPACK. I want to do Eigen analysis with QZ decomposition, but I'm not sure if I should start with LAPACKE or LAPACK. I appreciate any help.

Is Lapack open source?

LAPACK is built under Windows using Cmake the cross-platform, open-source build system. The new build system was developed in collaboration with Kitware Inc.

LAPACKE is the C wrapper for the standard F90 LAPACK library. Honestly, its easier (and more efficient) to do things directly with LAPACK just as long as you store things column-major. LAPACKE ends up calling (in some fashion) the LAPACK routines anyways.

You probably want to use LAPACKE as it frees you from writing helpers for converting from/to row-major mode to column major mode for matrices before/after LAPACK calls.