makedepend -- X Utility

Generate list of dependencies for a makefile
makedepend [-Dname=def] [-Dname] [-Iincludedir] [-Yincludedir]    [-a]   [-
fmakefile] [-oobjsuffix] [-pobjprefix] [-sstring] [-wwidth] [-v] [-m] [--
otheroption ...--] sourcefile ...

makedepend reads each sourcefile, and parses it as the C preprocessor does.
It processes every #include, #define, #undef, #ifdef, #ifndef, #endif, #if,
and  #else  directives  so  that  it  can  correctly  tell  which  #include
directives should  be used  in a  compilation.  Any #include  directive can
reference a file that  has other #include directives, and makedepend parses
these files as well.

Every  file that  a sourcefile  includes, directly  or indirectly,  is what
makedepend calls a dependency. It writes these dependencies into a makefile
in such  a way that  make will know  which object files  must be recompiled
when a dependency has changed.

By default, makedepend writes its output  into a file named makefile, if it
exists; otherwise,  it writes its output into Makefile.  You can specify an
alternate  makefile  with  the option  -f.  makedepend  first searches  the
makefile for the line

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

or  one provided  with the  option  -s as  a delimiter  for the  dependency
output.  If it finds the line,  it deletes everything after after this line
to the  end of  the makefile,  and writes its  output after this  line.  If
makedepend does not find this line, it appends the string to the end of the
makefile and writes the output after that.  For each sourcefile, makedepend
writes into the makefile  a line of the form

    sourcefile.o: dfile ...

where sourcefile.o  is the name of the sourcefile  with its suffix replaced
.o,  and dfile  is a  dependency that makedepend  discovered in  a #include
directive as it parsed sourcefile or one of the files it includes.

Command-line Options

makedepend ignores  any option it does  not understand, so you  can use the
same  arguments that  you would  for  cc. It  does recognize  the following
command-line options:

-Dsymbol[=def]
     Define  symbol  within makedepend's  internal  symbol table.   Without
     =def, makedepend defines it as 1.

-Iincludedir
     Tell makedepend  to prefix includedir onto the  list of directories to
     search  when   it  encounters  a  #include   directive.   By  default,
     makedepend only searches only /usr/include.

-Y[includedir]
     Search  includedir for  header files  instead of  all of  the standard
     header-file  directories.  If  you omit  to  name an  includedir, this
     option prevents searching of the standard header-file directories.

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

-ffile
     Write output into file instead of into makefile.

-oobjsuffix
     Append objectsuffix to a filename instead of the default .o.

-pobjprefix
     Prefix the  name of each  object file with objprefix.  This usually is
     used  to designate  a different  directory for  the object  file.  The
     default is the empty string.

-sstring
     Use string as the starting-string delimiter within a makefile.

-wwidth
     Set the  width of a  line of output  to width. By  default, makedepend
     limits a line of output to 78 characters.

-v   Verbose: tell makedepend to write onto the standard output the list of
     files that each input file includes.

-m   Warn about  multiple inclusion.  This option  tells makedepend to warn
     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.

-- option ... --
     makedepend ignores every option that it does not recognize and that is
     bracked by two hyphens `--'.   In  this   way,  you  can  safely  tell
     makedepend to  ignore esoteric compiler arguments  that might normally
     be found in a CFLAGS macro.  makedepend processes normally all options
     between the pair of double hyphens that recognizes.

Algorithm

To  speed  its  performance, makedepend  makes  two  assumptions about  the
programs whose dependency it is  mapping: first, that all files compiled by
a single makefile will be compiled with roughly the same -I and -D options;
and second, that most files in  a directory include largely the same files.
Given  these assumptions,  makedepend expects  to be  called once  for each
makefile, with  all source files that that  makefile maintains appearing on
its command line.

makedepend parses  each source and header file  exactly once, and maintains
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.  However, on  subsequent files, if makedepend
encounters a header  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.
Assume, further, that each  includes the header file header.h, and header.h
in turn includes the files def1.h and def2.h. When you run the command

    makedepend file1.c file2.c

makedepend parses  file1.c and, therefore, header.h  followed by def1.h and
def2.h. It then decides that the dependencies for this file are

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

When  makedepend  parses  file2.c  and  discovers  that it,  too,  includes
header.h, it does not re-parse that file, but simply adds header.h, def1.h,
and def2.h to the list of dependencies for file2.o.

Example

makedepend normally  is used within  a makefile target, so  that typing the
command

    make depend

brings 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,
commands,
make
X Windows Manual: imake

Notes

makedepend was written by Todd Brunhoff of Tektronix, Inc., and MIT Project
Athena.

© 2012 by Stephen A. Ness