#-----------------------------------------------------------------
# 	Makefile
# 
#	This file defines an 'implicit rule' to be used by the 
#	'make' utility when we want to compile a Linux module.
#	(It allows us to avoid typing the lengthy pathname for
#	the nonstandard subdirectory where the kernel's header
#	files are located, assuming this 'Makefile' resides in 
#	your current working directory.)
#
#	Usage: $ make <module-name>.o
#
#	E.g., compile 'mymodule.c' using: $ make mymodule.o
#
#
#	Reference: Stallman and McGrath, "GNU Make" (The Free 
#	Software Foundation, Incorporated, 1988).
#
#	programmer: ALLAN CRUSE
#	written on: 18 JAN 2003 
#	revised on: 09 JUL 2004 -- to incorporate 'uname' command
#-----------------------------------------------------------------

# which compiler to use
CC = gcc

# which control flags to use
CFLAGS = -O

# where to find the kernel header files
INCLUDE = /lib/modules/$(shell uname -r)/build/include

# a pattern rule that defines our own implicit rule
# invoked by using:	make mod.o
#
%.o : %.c %.h
	$(CC) -c $(CFLAGS) -I$(INCLUDE) $(<) 
#
# Here '$(<)' is the value of the automatic variable '<'
# which refers to the first of this rule's dependencies 
# [see Stallman and McGrath, pages 106-107].

# Added 01/20/2003: a pattern rule that defines another
# implicit rule, used by 'make' in case the dependency-
# list above is not matched by existing files (i.e., no
# header-file for our module).  If this 'fallback' rule
# is omitted, then 'make' resorts to its own 'built-in'
# pattern rule, which unfortunately omits including the
# essential headers needed to compile a kernel module.
%.o : %.c 
	$(CC) -c $(CFLAGS) -I$(INCLUDE) $(<)