INSTALLATION
------------

  a) Make sure you have a working vsprintf and vfprintf in your library.
     (If your system does not have them in your library, you can get
      a copy of the BSD4.3-tahoe stdio that is freely copyable.  It
      is available from uunet.uu.net.  For Minix systems, a vsprintf.c
      is included.)

  b) EDIT the Makefile for the correct definitions.  Read the comments in
     the the Makefile and make the changes needed.  (A "full" explanation
     of all the C defines are given at the end of this file.)  If your are
     on a MINIX machine, make sure the correct definitions for $O, $CFLAGS,
     and $LDFLAGS are uncommented in the makefile.
     NOTE: "configure" is a shell scritp that is automatically run by make
     to configure the bc source to your operating system.  You should still
     look at the Makefile.

  d) "make derived"  (If you need it.)
     The distribution contains the files bc.c.dist y.tab.h.dist and
     scan.c.dist.  These are provided so that you do not need a working 
     yacc and flex (lex).  This program was designed to work with the free
     programs byacc (berkeley yacc) and flex.  It should work with other
     versions of yacc and lex, but it is not guaranteed to work.

     If you do not have yacc or flex, give the command to get the *.dist
     files to their proper place.  This insures that make will not try
     to make these derived files from their original source.  Use the
     "make derived" before trying to compile bc.

  e) "make"
	compiles bc

  f) "make install"
	installs bc and libmath.b (if needed) in their directories.

  g) Use bc!


DEFINES
-------

  The following the are some defines that are automatically generated
  by the configure script.  In most cases, you do not need to deal
  with them.  The configure script is automatically run by make.

    BC_MATH_FILE=$(LIBFILE)
 	This defines the location of the math library file.  If you 
 	use this definition, the math library is read from LIBFILE.
 	If you do not define this, bc will include a "compiled" form
 	of the math library with the executable and will not need to
 	read any external file if the -l flag is given.

    VARARGS
        The variable args mechanism is assumed to be ANSI stdarg.
        Use -DVARARGS for Ultrix, SUN-OS, BSD, and other UNIX versions that
        use traditional varargs,
        For MINIX and ANSI compilers (gcc et al) do NOT use -DVARARGS.

    NO_LIMITS
        Use this for systems without the /usr/include/limits.h file.
        (BSD4.3 is one.) You should check the values of INT_MAX and 
        LONG_MAX in the file const.h if you use -DNO_LIMITS.

    NO_UNISTD
        Use this for systems without /usr/include/unistd.h.

    -DNO_STDLIB
        Use this for systems without /usr/include/stdlib.h.

    STRINGS_H
	Include the file <strings.h> instead of <string.h>.


  The following defines may need to be added by hand to the Makefile if
  you want them.  They are not generated by the configure script.
 
    -DOLD_EQ_OP
 	Causes bc to recognize =<op> as the same as <op>=.  The =<op> is
        the old style.  It makes "a =- 1" ambiguous.  With OLD_EQ_OP defined
        it is equivalent to "a -= 1" and with OLD_EQ_OP undefined it is
        equivalent to "a = -1".

    -DSMALL_BUF
        Use this IF you are using flex AND you have a systems with limited
        memory space.  If you use this, you should also use -DBC_MATH_FILE.
        This is "standard" for MINIX systems running on the IBM_PC.

    -DSHORTNAMES 
	If your compiler keeps a limited number of characters from names,
	you should include this define.  It is needed for the K&R compiler
	on MINIX and is automatically added for MINIX on the IBM_PC.

    -DDEBUG=n
 	Compile the debugging code.  The higher the number, the more
 	debugging code.  The degugging code is not very good.


POSSIBLE PROBLEMS
-----------------

  There might be some possible problems compiling due to different
  versions of the header files.  scan.c may require to edit out some
  definitions of malloc and free.  Others should compile with the
  correct set of defines.