MAKEDEPEND(1)							 MAKEDEPEND(1)



NAME
       makedepend - create dependencies in makefiles

SYNOPSIS
       makedepend  [ -Dname=def ] [ -Dname ] [ -Iincludedir ] [ -Yincludedir ]
       [ -a ] [ -fmakefile ] [ -oobjsuffix ] [ -pobjprefix ] [	-sstring  ]  [
       -wwidth ] [ -v ] [ -m ] [ -- otheroptions -- ] sourcefile ...

DESCRIPTION
       The  makedepend program reads each sourcefile in sequence and parses it
       like  a	C-preprocessor,  processing  all  #include,  #define,  #undef,
       #ifdef, #ifndef, #endif, #if, #elif and #else directives so that it can
       correctly tell which #include, directives would be used in  a  compila-
       tion.   Any  #include,  directives  can	reference  files  having other
       #include directives, and parsing 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 everything  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.

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

OPTIONS
       The program will ignore any option that it does not understand 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  the
	    standard  include directories (usually /usr/include and possibly a
	    compiler-dependent directory).

       -Yincludedir
	    Replace all of the standard include directories  with  the	single
	    specified include directory; you can omit the includedir to simply
	    prevent searching the standard include directories.

       -a   Append the dependencies to the end of the file instead of  replac-
	    ing them.

       -fmakefile
	    Filename.	This  allows  you  to specify an alternate makefile in
	    which makedepend can place its output.  Specifying	``-''  as  the
	    file  name (i.e., -f-) sends the output to standard output instead
	    of modifying an existing file.

       -oobjsuffix
	    Object file suffix.  Some systems may have object files whose suf-
	    fix  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.

       -pobjprefix
	    Object  file  prefix.   The prefix is prepended to the name of the
	    object file. This is usually used to designate a different	direc-
	    tory for the object file.  The default is the empty string.

       -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.

       -v   Verbose operation.	This option causes makedepend to emit the list
	    of files included by each input file on standard output.

       -m   Warn about multiple inclusion.  This option causes	makedepend  to
	    produce  a	warning  if  any input file includes another file more
	    than once.	In  previous  versions	of  makedepend	this  was  the
	    default behavior; the default has been changed to better match the
	    behavior of the C  compiler,  which  does  not  consider  multiple
	    inclusion  to  be  an error.  This option is provided for backward
	    compatibility, and to aid in debugging problems related to	multi-
	    ple inclusion.

       -- 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, makedepend can be made to safely ignore esoteric com-
	    piler  arguments  that  might  normally  be found in a CFLAGS make
	    macro (see the EXAMPLE section above).  All options  that  makede-
	    pend  recognizes and appear between the pair of double hyphens are
	    processed normally.

ALGORITHM
       The approach used in this program enables it to run an order of	magni-
       tude  faster  than any other ``dependency generator'' I have ever seen.
       Central to this performance are two assumptions: that  all  files  com-
       piled  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  maintained  by  the  makefile
       appearing  on the command line.	It parses each source and include file
       exactly once, maintaining 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  sub-
       sequent	files,	if  it	encounters 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 dependencies 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  simply adds
       header.h, def1.h and def2.h to the list of dependencies for file2.o.

SEE ALSO
       cc(1), make(1)

BUGS
       makedepend parses, but does not currently evaluate,  the  SVR4  #predi-
       cate(token-list)  preprocessor  expression; such expressions are simply
       assumed to be true.  This may cause the wrong #include directives to be
       evaluated.

       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 makedepend arrives at a list  of	depen-
       dencies for a file, it is cast in concrete.

AUTHOR
       Todd Brunhoff, Tektronix, Inc. and MIT Project Athena



4th Berkeley Distribution	  Release 6.1			 MAKEDEPEND(1)
