CMDS = hello hello_debug hello_opt
CC = gcc

# Always use -Wall when compiling.  Usually, any warning generated by
# this option is likely caused by a bug or a bug waiting to happen.
# To really enforce this, use the -Werror option, which causes
# warnings to be treated like errors, and makes the compile fail.

CFLAGS = -Wall

all: ${CMDS}

# We use the built-in implicit rule for .c files - the "hello" target
# is made automatically, using the CFLAGS and CC variables we defined
# above.

# Turn on some debugging information for use with gdb.

hello_debug: hello.c
	${CC} ${CFLAGS} -g -o $@ $<

# Optimize the program.

hello_opt: hello.c
	${CC} ${CFLAGS} -O3 -o $@ $<

clean:
	rm -f ${CMDS}