The APT Cache Specification describes the complete implementation and
format of the APT Cache file. The APT Cache file is a way for APT to parse
and store a large number of package files for display in the UI. It's primary
design goal is to make display of a single package in the tree very
fast by pre-linking important things like dependencies and provides.
The specification doubles as documentation for one of the in-memory
structures used by the package library and the APT GUI.
This document includes a list of all the PGPLOT subroutines,
and then gives detailed instructions for the use of each routine in
Fortran programs. The subroutine descriptions are in alphabetical