
makedepend(1)                Khoros                 makedepend(1)

PROGRAM
     makedepend - create dependencies in makefiles.

SYNTAX
     makedepend

     [-D]           definition for makedepend's symbol table

     [-I]           Include directory

     [-f]           Filename

     [-o]           Object file suffix

     [-s]           Starting string delimiter

     [-w]           Line width

     [- - otheroptions  - -]
                    ignore esoteric compiler arguments

     sourcefile ... the file(s) to depend.

DESCRIPTION
     Makedepend reads each sourcefile in sequence and parses it
     like a C-preprocessor, processing all #include, #define,
     #undef, #ifdef, #ifndef, #endif, #if and #else directives so
     that it can correctly tell which #include, directives would
     be used in a compilation.  Any #include, directives can
     reference files having other #include directives, and pars-
     ing will occur in these files as well.

     Every file that a sourcefile includes, directly or
     indirectly, is what makedepend calls a "dependency".  These
     dependencies are then written to a makefile in such a way
     that make(1) will know which object files must be recompiled
     when a dependency has changed.

     By default, makedepend places its output in the file named
     makefile if it exists, otherwise Makefile. An alternate
     makefile may be specified with the -f option.  It first
     searches the makefile for the line

         # DO NOT DELETE THIS LINE -- make depend depends on it.

     or one provided with the -s option, as a delimiter for the
     dependency output.  If it finds it, it will delete every-
     thing following this to the end of the makefile and put the
     output after this line.  If it doesn't find it, the program
     will append the string to the end of the makefile and place
     the output following that.  For each sourcefile appearing on
     the command line, makedepend puts lines in the makefile of
     the form

          sourcefile.o: dfile ...

     Where "sourcefile.o" is the name from the command line with
     its suffix replaced with ".o", and "dfile" is a dependency
     discovered in a #include directive while parsing sourcefile
     or one of the files it included.

     ALGORITHM

     The approach used in this program enables it to run an order
     of magnitude faster than any other "dependency generator" I
     have ever seen.  Central to this performance are two assump-
     tions:  that all files compiled by a single makefile will be
     compiled with roughly the same -I and -D options; and that
     most files in a single directory will include largely the
     same files.

     Given these assumptions, makedepend expects to be called
     once for each makefile, with all source files that are main-
     tained by the makefile appearing on the command line.  It
     parses each source and include file exactly once, maintain-
     ing an internal symbol table for each.  Thus, the first file
     on the command line will take an amount of time proportional
     to the amount of time that a normal C preprocessor takes.
     But on subsequent files, if it encounter's an include file
     that it has already parsed, it does not parse it again.

     For example, imagine you are compiling two files, file1.c
     and file2.c, they each include the header file header.h, and
     the file header.h in turn includes the files def1.h and
     def2.h. When you run the command

         makedepend file1.c file2.c

     makedepend will parse file1.c and consequently, header.h and
     then def1.h and def2.h. It then decides that the dependen-
     cies for this file are

         file1.o: header.h def1.h def2.h

     But when the program parses file2.c and discovers that it,
     too, includes header.h, it does not parse the file, but sim-
     ply adds header.h, def1.h and def2.h to the list of depen-
     dencies for file2.o.

REQUIRED ARGUMENTS
     sourcefile ...
          A list of sourcefiles to depend.

OPTIONAL ARGUMENTS
     Makedepend will ignore any option that it does not under-
     stand so that you may use the same arguments that you would
     for cc(1).

     -Dname=def or -Dname
          Define.  This places a definition for name in
          makedepend's symbol table.  Without =def the symbol
          becomes defined as "1".

     -Iincludedir
          Include directory.  This option tells makedepend to
          prepend includedir to its list of directories to search
          when it encounters a #include directive.  By default,
          makedepend only searches /usr/include.

     -fmakefile
          Filename.  This allows you to specify an alternate
          makefile in which makedepend can place its output.

     -oobjsuffix
          Object file suffix.  Some systems may have object files
          whose suffix is something other than ".o".  This option
          allows you to specify another suffix, such as ".b" with
          -o.b or ":obj" with -o:obj and so forth.

     -sstring
          Starting string delimiter.  This option permits you to
          specify a different string for makedepend to look for
          in the makefile.

     -wwidth
          Line width.  Normally, makedepend will ensure that
          every output line that it writes will be no wider than
          78 characters for the sake of readability.  This option
          enables you to change this width.

     - - options - -
          If makedepend encounters a double hyphen (- -) in the
          argument list, then any unrecognized argument following
          it will be silently ignored; a second double hyphen
          terminates this special treatment.  In this way, mak-
          edepend can be made to safely ignore esoteric compiler
          arguments that might normally be found in a CFLAGS make
          macro (see the EXAMPLE section above).  All options
          that makedepend recognizes and appear between the pair
          of double hyphens are processed normally.

EXAMPLE
     Normally, makedepend will be used in a makefile target so
     that typing "make depend" will bring the dependencies up to
     date for the makefile.  For example,
         SRCS = file1.c file2.c ...
         CFLAGS = -O -DHACK -I../foobar -xyz
         depend:
                 makedepend -- $(CFLAGS) -- $(SRCS)

SEE ALSO
     cc(1), make(1), makemake(1), imake(1), imkmf(1)

     Khoros Manual, Vol 2, Chapter 9 - Configuration Management

RESTRICTIONS
     If you do not have the source for cpp, the Berkeley C
     preprocessor, then makedepend will be compiled in such a way
     that all #if directives will evaluate to "true" regardless
     of their actual value.  This may cause the wrong #include
     directives to be evaluated.  Makedepend should simply have
     its own parser written for #if expressions.

     Imagine you are parsing two files, say file1.c and file2.c,
     each includes the file def.h. The list of files that def.h
     includes might truly be different when def.h is included by
     file1.c than when it is included by file2.c. But once mak-
     edepend arrives at a list of dependencies for a file, it is
     cast in concrete.

AUTHOR
     Original document written by:
     Todd Brunhoff, Tektronix, Inc. and MIT Project Athena

Khoros                    Release: 1.0                          1

