FLENS (Flexible Library for Efficient Numerical Solutions) is a C++ library for scientific computing. It can be considered as a very convenient and --- at the same time --- extremely efficient interface for BLAS and LAPACK. But it is much more than this
This library is a Fortran 95 gnuplot interface for some Unix like OS'es. This provides some routines that enables direct access of a child gnuplot session from a Fortran 95 program. You will need a copy of fortranposix to make this work.