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Table of Contents
imake - C preprocessor interface to the make
utility
imake [ -Ddefine ] [ -Idir ] [ -Udefine ] [ -Ttemplate ] [
-f filename ] [ -C filename ] [ -s filename ] [ -e ] [ -v ]
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.
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 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.
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 (\).
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
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.
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.
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
make(1)
, xmkmf(1)
S. I. Feldman, Make -- A Program for Maintaining Computer Programs
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.
Todd Brunhoff, Tektronix and MIT Project Athena;
Jim Fulton, MIT X Consortium
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