############################################################
# Compile hellolib_wrapper.c into a shareable object file
# on Linux, to be loaded dynamically when first imported.
#
# Note that Python programs import "hellowrap", which
# is (1) the name given to the module by the C init function 
# in hellolib_wrapper.c, (2) the suffix of the module init 
# function in hellolib_wrapper.c, and (3) the name of the .so 
# file which combines hellolib.c (the wrapped C library 
# file) with hellolib_wrapper.c (the C extension module).
#
# Since hellolib_wrapper.c uses a function in hellolib.c,
# we have to make sure that hellolib.c is also linked in 
# when Python code loads hellolib_wrapper.  The search for
# the wrapper module's .so uses the $PYTHONPATH var as usual, 
# but the wrapped library's file must be linked to the wrapper
# (and the Python process) using C linking techniques.
#
# This typically involves listing hellolib in a linker step
# of the makefile, to associate it with the wrapper.  For 
# instance, on Linux we might put hellolib.so in a dir listed
# on $LD_RUN_PATH ($LD_LIBRARY_PATH on Solaris), and link 
# hellolib.so with hellolib_wrapper in a ld (gcc) step in the
# makefile.  If dynamic loading isn't an option, we can also 
# statically link hellolib_wrapper to Python, via the 
# Modules/Setup file and re-make Python.
#
# In this Linux gcc makefile, the wrapped and wrapping files 
# are compiled to .o files and linked into a single composite
# .so, which Python loads when imported.  The alternative
# "makefile.hellolib-so" file instead compiles the wrapped
# and wrapping code to .so files, and links them into a
# single .so with the gcc '-rpath' flag (which works like 
# setting the $LD_RUN_PATH directory list env variable).
# On other platforms, see your compiler and linker docs.
############################################################

PY = $(MYPY)

hellowrap.so: hellolib_wrapper.o hellolib.o
	ld -shared hellolib_wrapper.o hellolib.o -o hellowrap.so

# wrapper module code
hellolib_wrapper.o: hellolib_wrapper.c hellolib.h
	gcc hellolib_wrapper.c -c -g -I. -I$(PY)/Include -I$(PY) 

# C library code
hellolib.o: hellolib.c hellolib.h
	gcc hellolib.c -c -g -I. 

clean:
	rm -f *.o *.so core