makedepend



MAKEDEPEND(1)                                                    MAKEDEPEND(1)




NAME

       makedepend - create dependencies in makefiles


SYNOPSIS

       makedepend  [ -Dname=def ] [ -Dname ] [ -Iincludedir ] [ -Yincludedir ]
       [ -a ] [ -fmakefile ] [ -include file ] [ -oobjsuffix ] [ -pobjprefix ]
       [  -sstring  ] [ -wwidth ] [ -v ] [ -m ] [ -- otheroptions -- ] source-
       file ...


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 makedepends  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.

       -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 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.

       -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                                        MAKEDEPEND(1)

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