makedepend(1X) makedepend(1X)
NAME
makedepend - create dependencies in makefiles
SYNOPSIS
makedepend [-Dname=def] [-Dname] [-Iincludedir] [-Yincludedir] [-a] [-fmakefile] [-oobjsuffix] [-pobjprefix] [-sstring] [-wwidth] [-v] [-m]
[-- otheroptions --] sourcefile ...
OPTIONS
Makedepend will ignore any option that it does not understand so that you may use the same arguments that you would for cc(1). Define.
This places a definition for name in makedepend's symbol table. Without =def the symbol becomes defined as "1". 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). 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. Append the dependencies to the end of the file instead of replacing them. Filename. This allows you to
specify an alternate makefile in which makedepend can place its output. 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. 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. Starting string delimiter. This option permits you to specify a different string for
makedepend to look for in the makefile. 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. Verbose operation. This option causes
makedepend to emit the list of files included by each input file on standard output. 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. 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 compiler arguments
that might normally be found in a CFLAGS make macro (see the EXAMPLE section below). All options that makedepend recognizes and appear
between the pair of double hyphens are processed normally.
DESCRIPTION
makedepend reads each sourcefile in sequence and parses it like a C-preprocessor, processing all #include, #define, #undef, #ifdef, #ifn-
def, #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 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 writ-
ten 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)
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 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 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.
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.
SEE ALSO
cc(1), make(1)
AUTHOR
Todd Brunhoff, Tektronix, Inc., and MIT Project Athena
makedepend(1X)