This archive contains two main products:  the fileCompare program,
and the replaceIfDifferent script.

*****************      * FILECOMPARE *   **************************

FileCompare determines whether two files have identical contents.


Usage:

 fileCompare oneFile anotherFile.

Returns:

 OK    status  (0) if both files exist and have identical contents

 WARN  status  (5) if both files exist but have different contents

 ERROR status (10) if either file doesn't exist

 FAIL  status (20) if something horrible happens, like identical block
                   read operations on files of supposedly equal sizes
                   returning different quantities of data


FileCompare is `pure' code, and may be made resident.



This operation is becoming more useful now that compilers can be
coaxed into generating function prototype files for all the functions
in an xxx.c source file.  A makefile that attempts to automate such
prototype generation would show the "xxx.protos" as being dependent
on "xxx.c", and (one way or another), vice-versa.  Since make is
unable to gague the magnitude of changes, it will dutifully re-extract
the function prototypes whenever there is a change, however slight,
in the associated source file.  And then, since a new prototype file
HAS been generated, all files listed as dependents on the prototype
will have to be recompiled.

One easy way out of this difficulty is to have the prototypes generated
in a "temporary" file, which is then compared against the "official"
prototype file.  Only if the new prototype file is actually *different*
does it replace the old copy.



*****************      * REPLACEIFDIFFERENT *   ************************

A file comparison utility, by itself, is not sufficient to support the
kind of makefile described above; at least, not for the version of make
I use (the one that came with my Manx Aztec C compiler).  Unfortunately,
the commands this make allows are limited to legal AmigaDOS commands,
which means that no conditional testing and branching is possible among
the commands that make will run when it's trying to build a target.

I've written a script called "replaceIfDifferent" (AmigaDOS Execute scripts
are the only places where the testing & branching operations if, then, else,
etc. work).  This script will run the fileCompare program on a pair of files
specified as arguments to the script, and replaces the second file with the
first one, in the event that they are different.