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 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 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 configura-
	       tion 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 constructed 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 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 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 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)

       Imake also replaces any occurrences of the word ``XCOMM'' with the character ``#'' to permit placing comments in the Makefile without caus-
       ing ``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
       corresponding 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 com-
       mand 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 UseInstalled is defined and TOPDIR and CURDIR are omitted.  If the  con-
       figuration 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 indentation 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 symbols.

FILES

       Imakefile.c		     temporary input file for cpp
       /tmp/Imf.XXXXXX		     temporary Makefile for -s
       /tmp/IIf.XXXXXX		     temporary Imakefile if specified Imakefile 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 pro-
	    gram 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 Consortium

X Version 11							    Release 6.6 							  IMAKE(1)