dos_compilers/Mix C v202/READ.ME

                              Mix C                                2.0.2

                    New Features in version 2.0
                    ---------------------------

. Maximum length of a line is increased to 256 characters

. Keywords are recognized in lower case only.  The compiler
  option /*$KEYWCASE*/ may be used to switch to upper and mixed
  case for keywords

. On the listing, lines are numbered separately for each include
  file.  A letter (a .. z) is present on the left of each line from
  an include file to indicate the depth of includes.

. When errors occur in include files, the error file (C.ERR) will
  have the name of the file as well as the line in error.

. Include files have a default extension of ".H" .  If a file name
  in a #include does not have an extension, the compiler looks first
  for the file as specified.  If no file exists by that name, the
  compiler trys the same name with ".H" as an extension.

. Initializers are supported for float and double.  Initializers for
  auto variables may use constant expressions.  Initializers for float
  and double static or global variables allow only a constant.

. Hexadecimal character constants are supported and hexadecimal
  characters may be included in strings.  They are represented by
  a backslash followed by "x" and a two digit hexadecimal number.
        Examples:
               '\x30'    is the character '0'
               "ab\x63d" is equivalent to "abcd"

. Enumerations are supported.  Enumerations are declared similar
  to structures with the keyword "enum".  The braces contain a
  list of identifiers with optional initialization values.  Values
  are assigned starting at zero and increasing by one for each
  identifier.  If an intialization value is present, the corresponding
  identifier is assigned the value supplied and counting continues
  from that point.

     Examples:
         enum primecolor {red, blue, green} c;
         /* declares a variable of type primecolor.  The identifiers
            are assigned values: red=0, blue=1, green=2.
            */
         typedef enum {orange, yellow=8, pink, aqua} color;
         /* defines the type color.  The values of the colors are:
            orange=0, yellow=8, pink=9, aqua=10
            */

         c = blue;  /* assigns the value "blue" (1) to c */


  . Structures and unions may be passed as parameters to functions.
    They are passed by value.

  . Functions may return structures or unions as results.

  . The compiler has a command line option to redirect the object
    code to a different file.  "-ofilename.ext" will place the object
    code in the specified file.  "-o" with not file name will cause
    the compiler to not generate object code.


                        Optional Patches
                        ----------------

   Some people may wish to change some of the file names used by Mix C
so that it will use a different disk drive or directory.  The addresses
of these file names are listed below.  You can use the debug utility
supplied with MSDOS to change the names to the ones that you prefer.
Mix C will search for the error messages ("CERRORS.DAT") in the default
directory and all directories listed in the path string in the
environment.  See the msdos manual for a description of the "PATH"
command.  Most users will not need to change this.  Be sure to make a
copy of the original disk before attempting to make the changes.  The
file names are strings of characters up to 15 characters in length and
terminated by a binary zero.

   CERRORS.DAT      DBAD     Error messages file
   C.ERR            6804     File for lines in error
   A:               D6CF     Prefix for include files that are
                             enclosed in "<>"

Example:

   To make the #include preprocessor statement use drive C, directory "MIXC"
   as the system device (ie for file names enclosed in "< >") you would
   use debug to make the patch as illustrated below.

   C>debug cc.com
   -ed6cf "C:\MIXC\"                 ;Patch in path name
   -W                                ;Write cc.com back to disk
   Writing ED00 bytes
   -Q                                ;Exit debugger
   C>


   The Mix linker also has some file names that are built in.  In some
applications you may wish to change one or more of these names.  Each
file name can be up to 31 bytes long and must be terminated by a zero
byte.  These names are changed in the same way as illustrated above.

   "RUNTIME.OVY"  391C    Default name for the runtime support file
   "CLIB.MIX"     3A14    Library that is searched for standard functions.
   "LINKER.MIX"   3AA5    Library that is searched if clib does not contain
                          all referenced functions.
   "A:" and "A:\" 3AC5    Directory prefix used to search for runtime.ovy .
                          Each prefix is terminated by a zero, and the entire
                          list is terminated by two zeros.
Example:

   The following example patches the linker to search for its files in
   directory MIXC on drive C.

   C>debug linker.com
   -ed3AC5 "C:\MIXC\"                ;Patch in path name
   -W                                ;Write linker.com back to disk
   Writing 3D00 bytes
   -Q                                ;Exit debugger
   C>

When the short form of the linker is used to build a command file, the
runtime support routines are not inlcuded in the file.  To make the linker
include the runtime by default, make the following change.

   A>debug linker.com
   -e72c
   09FE:072C  32.b0  C0.01
   -w
   Writing 3D00 bytes
   -q
   A>

Note: When using the change command in the linker to use a different
      runtime file, the change command must be executed before any
      load commands.  The linker must know the size of the runtime so
      it can perform relocation as it loads the program.