X Version 11 (Release 5)

imake(XS)

imake -- C preprocessor interface to the make utility

Syntax

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 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.
-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.
-ffilename: This option specifies the name of the per-directory input file. The default is Imakefile.
-sfilename: 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 that 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. If the Imakefile contains any lines beginning with a '#' character that is not followed by a cpp directive (#include, #define, #undef, #ifdef, #else, #endif, or #if), imake will produce a temporary makefile in which the '#' lines are prepended with the string ``/**/'' (so that cpp will copy the line into the Makefile as a comment).

The Imakefile reads in a file containing machine-dependent parameters (specified as cpp symbols), a site-specific parameters file, 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.

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 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 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.

The command make Makefiles can then be used to generate Makefiles in any subdirectories.

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

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 preprocessor. For example, -I/usr/include/local. Actually, any valid cpp argument will work here.
IMAKECPP: If defined, this should be a valid path to a preprocessor program. For example, /usr/local/cpp. By default, imake will use /lib/cpp.
IMAKEMAKE: If defined, this should be a valid path to a make program. For example, /usr/local/make. By default, imake will use whatever make program is found using execvp(S).

Bugs

Comments should be preceded by ``/**/#'' to protect them from cpp.