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 used 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
configuration 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
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
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 used imake extensively up through the X11R6.9
release, for both full builds within the source tree and external
software. X has since moved to GNU autoconf and automake for its build
system in X11R7.0 and later releases, but still maintains imake for
building existing external software programs that have not yet
converted.
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 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
configuration 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)
Paul DuBois, imake-Related Software and Documentation,
http://www.snake.net/software/imake-stuff/
Paul DuBois, Software Portability with imake, Second Edition, O’Reilly
& Associates, 1996.
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
Consortium