IMAKE(1)		    General Commands Manual		      IMAKE(1)



NAME
       imake - C preprocessor interface to the make utility

SYNOPSIS
       imake  [ -Ddefine ] [ -Idir ] [ -Udefine ] [ -Ttemplate ] [ -f filename
       ] [ -C 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 as compiler options,  alternate  com-
       mand  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	direc-
	       tory  containing 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 configu-
	       ration files may be found.

       -Udefine
	       This option is passed directly to cpp.  It is typically used to
	       unset variables when debugging imake configuration files.

       -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.

       -C filename
	       This option specifies the name of the  .c  file	that  is  con-
	       structed in the current directory.  The default is Imakefile.c.

       -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 generate, 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 the name of a file containing 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 com-
       mand options, respectively.

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

       Imake configuration files contain two types of variables,  imake	 vari-
       ables  and  make variables.  The imake variables are interpreted by cpp
       when imake is run.  By convention they are mixed case.  The make	 vari-
       ables  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	direc-
       tory)  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)


       Imake also replaces any occurrences of  the  word  ``XCOMM''  with  the
       character  ``#''	 to  permit  placing  comments in the Makefile without
       causing ``invalid directive'' errors from the preprocessor.

       Some complex imake macros require generated  make  variables  local  to
       each  invocation	 of  the  macro,  often because their value depends on
       parameters passed to the macro.	Such variables can be created by using
       an  imake  variable of the form XVARdefn, where n is a single digit.  A
       unique make variable will be substituted.   Later  occurrences  of  the
       variable	 XVARusen will be replaced by the variable created by the cor-
       responding XVARdefn.

       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 command 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
       variables,  TOPDIR  and CURDIR, are set to make referencing files using
       relative path names easier.  For example, the following command is gen-
       erated  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 Use-
       Installed is defined and TOPDIR and CURDIR are omitted.	If the config-
       uration files have been properly installed, the script xmkmf(1) may  be
       used.

INPUT FILES
       Here  is a summary of the files read by imake as used by X.  The inden-
       tation shows what files include what other files.

	   Imake.tmpl		     generic variables
	       site.def		     site-specific, BeforeVendorCF defined
	       *.cf		     machine-specific
		   *Lib.rules	     shared library rules
	       site.def		     site-specific, AfterVendorCF defined
	       Imake.rules	     rules
	       Project.tmpl	     X-specific variables
		   *Lib.tmpl	     shared library variables
	       Imakefile
		   Library.tmpl	     library rules
		   Server.tmpl	     server rules
		   Threads.tmpl	     multi-threaded 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 sym-
       bols.

FILES
       Imakefile.c		     temporary input file for cpp
       /tmp/Imf.XXXXXX		     temporary Makefile for -s
       /tmp/IIf.XXXXXX		     temporary Imakefile if  specified	Imake-
       file uses # comments
       /usr/bin/cpp		     default C preprocessor

SEE ALSO
       make(1), xmkmf(1)
       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	specifies a ``-I'' include argument to pass to
	    the C preprocessor.	 E.g., ``-I/usr/X11/config''.

       IMAKECPP
	    If defined, this should be a valid path to a preprocessor program.
	    E.g.,  ``/usr/local/cpp''.	 By  default,  imake will use cc -E or
	    /usr/bin/cpp, depending on the OS specific configuration.

       IMAKEMAKE
	    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(3).  This variable is only  used  if
	    the ``-e'' option is specified.

AUTHOR
       Todd Brunhoff, Tektronix and MIT Project Athena; Jim Fulton, MIT X Con-
       sortium



X Version 11			  imake 1.0.2			      IMAKE(1)