qhull/src/libqhull

    This directory contains the non-reentrant version of qhull, libqhull.
    
    New code should use the reentrant version of qhull (libqhull_r).
    It allows multiple instances of qhull to run at the same time. On 
    modern architectures, it is nearly as fast as libqhull.   
    
    Qhull programs may be built with either library.  Each program has a
    reentrant version (e.g., qconvex_r.c) and a non-reentrant 
    version (qconvex.c).   The programs, rbox, qconvex, qdelaunay, qhalf, 
    and qvoronoi, are built with libqhull.  The qhull program is built 
    with libqhull_r.

    Qhull's C++ interface requires libqhull_r.  If you previously used the 
    C++ interface with libqhull, you will need to update your code to libqhull_r.
    See qh-code.htm#convert and Changes.txt for suggestions.
     
    The C code in libqhull looks unusual because of the 'qh' macro.  The 'qh'
    macro controls access to Qhull's global data structure, qhT.  If 
    'qh_QHpointer' is defined, 'qh' is 'qh_qh->' and 'qh_qh' is defined as
    'qhT *qh_qh', otherwise 'qh' is 'qh_qh.' and 'qh_qh' is defined as
    'qhT qh_qh'.  This allows dynamic allocation of qh_qh without modifying
    the code.  Reentrant Qhull is a better solution.

    libqhull will be supported indefinitely.  The qh_QHpointer variation
    of libqhull will be not be retested each release.  It is replaced by 
    libqhull_r.