#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 (\).
% ../.././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.
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
/lib/cpp default C preprocessor