MAKEDEPEND(1)						      General Commands Manual						     MAKEDEPEND(1)

NAME

       makedepend - create dependencies in makefiles

SYNOPSIS

       makedepend  [ -Dname=def ] [ -Dname ] [ -Iincludedir ] [ -Yincludedir ] [ -a ] [ -fmakefile ] [ -include file ] [ -oobjsuffix ] [ -pobjpre-
       fix ] [ -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 compi-
       lation.	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 speci-
       fied 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  com-
	    piler-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 replacing 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.

       -include file
	    Process  file  as input, and include all the resulting output before processing the regular input file. This has the same affect as if
	    the specified file is an include statement that appears before the very first line of the regular input file.

       -oobjsuffix
	    Object file suffix.  Some systems may have object files whose suffix is something other than ``.o''.  This option allows you to  spec-
	    ify 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 directory
	    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.

       -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 multiple 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 makedepend rec-
	    ognizes 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 magnitude faster than any other ``dependency generator'' I have ever seen.
       Central to this performance are two assumptions: 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 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 subsequent 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 #predicate(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					 makedepend 1.0.2						     MAKEDEPEND(1)