Return a pointer (coded as a double) to the segment
of section that
contains location x.
If no section is specified, it uses the currently accessed section; see
cas(). If you wish to compute a segment number
index where 1 is the first nonzero area segment and nseg is the last
nonzero area segment
of the currently accessed section corresponding to position x use the
hoc function
Return a pointer (coded as a double) to the section which contains location 0 of the
currently accessed section. This pointer can be used as the argument
to push_section(). Functions that return pointers coded as doubles
are unsafe with 64 bit pointers. This function has been superseded by
SectionRef. See sec().