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.TH MAKEDEPEND 1 "Release 6.1" "X Version 11"

.UC 4

.SH NAME

makedepend \- create dependencies in makefiles

.SH SYNOPSIS

.B makedepend

[

.BI \-D name\fB=\fPdef

] [

.BI \-D name

] [

.BI \-I includedir

] [

.BI \-Y includedir

] [

.B \-a

] [

.BI \-f makefile

] [

.BI \-o objsuffix

] [

.BI \-p objprefix

] [

.BI \-s string

] [

.BI \-w width

] [

.B \-v

] [

.B \-m

] [

\-\^\-

.I otheroptions

\-\^\-

]

.I sourcefile

\&.\|.\|.

.br

.SH DESCRIPTION

The

.B makedepend

program reads each

.I sourcefile

in sequence and parses it like a C-preprocessor,

processing all

.I #include,

.I #define,

.I #undef,

.I #ifdef,

.I #ifndef,

.I #endif,

.I #if,

.I #elif

and

.I #else

directives so that it can correctly tell which

.I #include,

directives would be used in a compilation.

Any

.I #include,

directives can reference files having other

.I #include

directives, and parsing will occur in these files as well.

.PP

Every file that a

.I sourcefile

includes,

directly or indirectly,

is what

.B makedepend

calls a \fIdependency.\fP

These dependencies are then written to a

.I makefile

in such a way that

.B make(1)

will know which object files must be recompiled when a dependency has changed.

.PP

By default,

.B makedepend

places its output in the file named

.I makefile

if it exists, otherwise

.I Makefile.

An alternate makefile may be specified with the

.B \-f

option.

It first searches the makefile for

the line

.sp

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

.sp

or one provided with the

.B \-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

.I sourcefile

appearing on the command line,

.B makedepend

puts lines in the makefile of the form

.sp

     sourcefile.o:\0dfile .\|.\|.

.sp

Where \fIsourcefile.o\fP is the name from the command

line with its suffix replaced with ``.o'',

and \fIdfile\fP is a dependency discovered in a

.I #include

directive while parsing

.I sourcefile

or one of the files it included.

.SH EXAMPLE

Normally,

.B makedepend

will be used in a makefile target so that typing ``make depend'' will

bring the dependencies up to date for the makefile.

For example,

.nf

    SRCS\0=\0file1.c\0file2.c\0.\|.\|.

    CFLAGS\0=\0\-O\0\-DHACK\0\-I\^.\^.\^/foobar\0\-xyz

    depend:

            makedepend\0\-\^\-\0$(CFLAGS)\0\-\^\-\0$(SRCS)

.fi

.SH OPTIONS

The program

will ignore any option that it does not understand so that you may use

the same arguments that you would for

.B cc(1).

.TP 5

.B \-D\fIname\fP=\fIdef\fP \fRor\fP \-D\fIname\fP

Define.

This places a definition for

.I name

in

.B makedepend's

symbol table.

Without 

.I =def\|

the symbol becomes defined as ``1''.

.TP 5

.B \-I\fIincludedir\fP

Include directory.

This option tells

.B makedepend

to prepend

.I includedir

to its list of directories to search when it encounters

a

.I #include

directive.

By default,

.B makedepend

only searches the standard include directories (usually /usr/include

and possibly a compiler-dependent directory).

.TP 5

.B \-Y\fIincludedir\fP

Replace all of the standard include directories with the single specified

include directory; you can omit the

.I includedir

to simply prevent searching the standard include directories.

.TP 5

.B \-a

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

.TP 5

.B \-f\fImakefile\fP

Filename.

This allows you to specify an alternate makefile in which

.B makedepend

can place its output.

Specifying ``\-'' as the file name (i.e., \fB\-f\-\fP) sends the

output to standard output instead of modifying an existing file.

.TP 5

.B \-o\fIobjsuffix\fP

Object file suffix.

Some systems may have object files whose suffix is something other

than ``.o''.

This option allows you to specify another suffix, such as

``.b'' with

.I \-o.b

or ``:obj''

with

.I \-o:obj

and so forth.

.TP 5

.B \-p\fIobjprefix\fP

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.

.TP 5

.B \-s\fIstring\fP

Starting string delimiter.

This option permits you to specify

a different string for

.B makedepend

to look for in the makefile.

.TP 5

.B \-w\fIwidth\fP

Line width.

Normally,

.B 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.

.TP 5

.B \-v

Verbose operation.

This option causes 

.B makedepend

to emit the list of files included by each input file on standard output.

.TP 5

.B \-m

Warn about multiple inclusion.

This option causes 

.B makedepend

to produce a warning if any input file includes another file more than

once.  In previous versions of 

.B 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.

.TP 5

.B "\-\^\- \fIoptions\fP \-\^\-"

If

.B 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,

.B makedepend

can be made to safely ignore esoteric compiler arguments that might

normally be found in a CFLAGS

.B make

macro (see the

.B EXAMPLE

section above).

All options that

.B makedepend

recognizes and appear between the pair of double hyphens

are processed normally.

.SH 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 \-I

and

.I \-D

options;

and that most files in a single directory will include largely the

same files.

.PP

Given these assumptions,

.B 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.

.PP

For example,

imagine you are compiling two files,

.I file1.c

and

.I file2.c,

they each include the header file

.I header.h,

and the file

.I header.h

in turn includes the files

.I def1.h

and

.I def2.h.

When you run the command

.sp

    makedepend\0file1.c\0file2.c

.sp

.B makedepend

will parse

.I file1.c

and consequently,

.I header.h

and then

.I def1.h

and

.I def2.h.

It then decides that the dependencies for this file are

.sp

    file1.o:\0header.h\0def1.h\0def2.h

.sp

But when the program parses

.I file2.c

and discovers that it, too, includes

.I header.h,

it does not parse the file,

but simply adds

.I header.h,

.I def1.h

and

.I def2.h

to the list of dependencies for

.I file2.o.

.SH "SEE ALSO"

cc(1), make(1)

.SH BUGS

.B 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

.I #include

directives to be evaluated.

.PP

Imagine you are parsing two files,

say

.I file1.c

and

.I file2.c,

each includes the file

.I def.h.

The list of files that

.I def.h

includes might truly be different when

.I def.h

is included by

.I file1.c

than when it is included by

.I file2.c.

But once

.B makedepend

arrives at a list of dependencies for a file,

it is cast in concrete.

.SH AUTHOR

Todd Brunhoff, Tektronix, Inc. and MIT Project Athena