imake(1X)							    imake(1X)
X11R5									X11R5



NAME

  imake - C preprocessor interface to the make utility

SYNOPSIS

  imake [ -Ddefine ] [ -Idir ] [ -Ttemplate ] [ -f filename ] [ -s filename ]
  [ -e ] [ -v ]

DESCRIPTION

  Imake is used to generate Makefiles from a template, a set of cpp macro
  functions, and a per-directory input file called an Imakefile.  This allows
  machine dependencies (such has compiler options, alternate command names,
  and special make rules) to be kept separate from the descriptions of the
  various items to be built.

OPTIONS

  The following command line options may be passed to imake:

  -Ddefine
	  This option is passed directly to cpp.  It is typically used to set
	  directory-specific variables.	 For example, the X Window System
	  uses this flag to set TOPDIR to the name of the directory contain-
	  ing the top of the core distribution and CURDIR to the name of the
	  current directory, relative to the top.

  -Idirectory
	  This option is passed directly to cpp.  It is typically used to
	  indicate the directory in which the imake template and configura-
	  tion files may be found.

  -Ttemplate
	  This option specifies the name of the master template file (which
	  is usually located in the directory specified with -I) used by cpp.
	  The default is Imake.tmpl.

  -f filename
	  This option specifies the name of the per-directory input file.
	  The default is Imakefile.

  -s filename
	  This option specifies the name of the make description file to be
	  generated but make should not be invoked.  If the filename is a
	  dash (-), the output is written to stdout.  The default is to gen-
	  erate, but not execute, a Makefile.

  -e	  This option indicates the imake should execute the generated
	  Makefile.  The default is to leave this to the user.

   -v	  This option indicates that imake should print the cpp command line
	  that it is using to generate the Makefile.

HOW IT WORKS

  Imake invokes cpp with any -I or -D flags passed on the command line and
  passes it the following 3 lines:

		  #define IMAKE_TEMPLATE "Imake.tmpl"
		  #define INCLUDE_IMAKEFILE "Imakefile"
		  #include IMAKE_TEMPLATE

  where Imake.tmpl and Imakefile may be overridden by the -T and -f command
  options, respectively.

  The IMAKE_TEMPLATE typically reads in a file containing machine-dependent
  parameters (specified as cpp symbols), a site-specific parameters file, a
  file defining variables, a file containing cpp macro functions for generat-
  ing make rules, and finally the Imakefile (specified by INCLUDE_IMAKEFILE)
  in the current directory.  The Imakefile uses the macro functions to indi-
  cate what targets should be built; imake takes care of generating the
  appropriate rules.

  Imake configuration files contain two types of variables, imake variables
  and make variables.  The imake variables are interpreted by cpp when imake
  is run.  By convention they are mixed case.  The make variables are written
  into the Makefile for later interpretation by make. By convention make
  variables are upper case.

  The rules file (usually named Imake.rules in the configuration directory)
  contains a variety of cpp macro functions that are configured according to
  the current platform.	 Imake replaces any occurrences of the string ``@@''
  with a newline to allow macros that generate more than one line of make
  rules.  For example, the macro

  #define   program_target(program, objlist)@@\
  program:  objlist		       @@\
	    $(CC)  -o  $@  objlist  $(LDFLAGS)

  when called with program_target(foo, foo1.o  foo2.o) will expand to

  foo:	    foo1.o  foo2.o
	    $(CC)  -o  $@  foo1.o  foo2.o  $(LDFLAGS)


  On systems whose cpp reduces multiple tabs and spaces to a single space,
  imake attempts to put back any necessary tabs (make is very picky about the
  difference between tabs and spaces).	For this reason, colons (:) in com-
  mand lines must be preceded by a backslash (\).

USE WITH THE X WINDOW SYSTEM

  The X Window System uses imake extensively, for both full builds within the
  source tree and external software.  As mentioned above, two special vari-
  ables, TOPDIR and CURDIR, are set to make referencing files using relative
  path names easier.  For example, the following command is generated
  automatically to build the Makefile in the directory lib/X/ (relative to
  the top of the sources):

	    %  ../.././config/imake  -I../.././config  \
		  -DTOPDIR=../../.   -DCURDIR=./lib/X

  When building X programs outside the source tree, a special symbol UseIn-
  stalled is defined and TOPDIR and CURDIR are omitted.	 If the configuration
  files have been properly installed, the script xmkmf(1X) may be used.


INPUT FILES

  Here is a summary of the files read by imake as used by X.  The indentation
  shows what files include what other files.

      Imake.tmpl      generic variables
	  site.def    site-specific, BeforeVendorCF defined
	  *.cf	      machine-specific
	      *Lib.rulesshared library rules
	  site.def    site-specific, AfterVendorCF defined
	  Project.tmplX-specific variables
	      *Lib.tmplshared library variables
	  Imake.rules rules
      Imakefile
	  Library.tmpllibrary rules
	  Server.tmpl server rules

  Note that site.def gets included twice, once before the *.cf file and once
  after.  Although most site customizations should be specified after the
  *.cf file, some, such as the choice of compiler, need to be specified
  before, because other variable settings may depend on them.

  The first time site.def is included, the variable BeforeVendorCF is
  defined, and the second time, the variable AfterVendorCF is defined.	All
  code in site.def should be inside an #ifdef for one of these symbols.

FILES

  /usr/tmp/tmp-imake.nnnnnn	temporary input file for cpp
  /usr/tmp/tmp-make.nnnnnn	temporary input file for make
  /lib/cpp			default C preprocessor

RELATED INFORMATION

  Commands: make(1), xmkmf(1X)
  S. I. Feldman, Make - A Program for Maintaining Computer Programs

ENVIRONMENT VARIABLES

  The following environment variables may be set, however their use is not
  recommended as they introduce dependencies that are not readily apparent
  when imake is run:

  IMAKEINCLUDE
       If defined, this should be a valid include argument for the C prepro-
       cessor.	E.g., ``-I/usr/include/local''.	 Actually, any valid cpp
       argument will work here.

  *    If defined, this should be a valid path to a preprocessor program.
       E.g. ``/usr/local/cpp''.	 By default, imake will use /lib/cpp.

  *    If defined, this should be a valid path to a make program, such as
       ``/usr/local/make''.  By default, imake will use whatever make program
       is found using execvp(2).  This variable is only used if the ``-e''
       option is specified.

AUTHOR

  Todd Brunhoff, Tektronix and MIT Project Athena; Jim Fulton, MIT X Consor-
  tium