Define global variables.

  GLOBAL X Y Z defines X, Y, and Z as global in scope.



  Ordinarily, each MATLAB function, defined by an M-file, has its

  own local variables, which are separate from those of other functions,

  and from those of the base workspace and non-function scripts.

  However, if several functions, and possibly the base workspace,

  all declare a particular name as GLOBAL, then they all share

  a single copy of that variable.  Any assignment to that variable,

  in any function, is available to all the other functions declaring

  it GLOBAL.



  Stylistically, global variables often have long names with all

  capital letters, but this is not required.



  For an example, see the functions TICN2UBU2 and TOC22EHAXR.