Red Antigua - C tutorials - Makefile examples

Here is an example of how to build a shared library on FreeBSD of some object files, and then build an executable of some other object files, and finally link them together.
This Makefile has been tested with BSD make.
This example comes with no source code. It is just an example how to use compiler and linker flags to create a shared library on FreeBSD.
Note specially the following lines:

DEFAULT_LIB_INSTALL_PATH=./
SHARED_LDFLAGS=-Wl,-rpath,$(DEFAULT_LIB_INSTALL_PATH)

With these compiler/linker flags, there is no need to use environment variables such as LD_LIBRARY_PATH.
These flags can be ignored if a library will be installed in one of the standard paths /lib/, /usr/lib/, or /usr/local/lib/, but during development and testing of a library, it is recommended to use an alternative path to not mix them with possible existing older versions of the same library.
In this case, DEFAULT_LIB_INSTALL_PATH is set to the same path as the executable.

Makefile:

# Example BSD Makefile for building a shared library, object files, an executable, and linking them alltogether.

# Executable
PROG = arithmetic
OBJS = main.o arithmetic.o kldgrep.o
OBJS_BSD = kldgrep.o
HEADERS = arithmetic.h

# Shared library
CODEC_OBJS = codec-alaw-mulaw.o codec-8bit.o codec-16bit.o codec-24bit.o codec-32bit.o
CODEC_HEADERS = codec.h
CODEC_LIB=libcodec.so
PICFLAGS = -fpic 
DEFAULT_LIB_INSTALL_PATH=./
SHAREDFLAGS = -shared
SHARED_LDFLAGS=-Wl,-rpath,$(DEFAULT_LIB_INSTALL_PATH)
CODEC_LDFLAGS =  -L$(DEFAULT_LIB_INSTALL_PATH) -lcodec

# Compiler & linker options
CC = gcc
DEBUGFLAGS = -g
WARNFLAGS_BSD = -fno-strict-aliasing -pipe  -Wsystem-headers -Wall -Wno-format-y2k -W -Wno-unused-parameter -Wstrict-prototypes \
-Wmissing-prototypes -Wpointer-arith -Wreturn-type -Wcast-qual -Wwrite-strings -Wswitch -Wshadow -Wcast-align -Wunused-parameter -Wno-pointer-sign
OPTFLAGS = -O2
LDFLAGS = -lm -lpthread
CFLAGS = $(DEBUGFLAGS) $(OPTFLAGS) $(WARNFLAGS) $(WARNFLAGS_BSD)


# Emacs TAGS
ETAGS_ARGS = find . -name "*.[ch]"


all: bsdlib bsd


bsd:  $(OBJS) $(OBJS_BSD)
        $(CC) $(DEBUGFLAGS) $(OPTFLAGS) $(WARNFLAGS_BSD) $(OBJS) $(OBJS_KLD) $(LDFLAGS) $(SHARED_LDFLAGS) $(CODEC_LDFLAGS) -o $(PROG)


# Codec Library
lib: bsdlib
bsdlib: $(CODEC_OBJS)
        $(CC) $(DEBUGFLAGS) $(OPTFLAGS) $(WARNFLAGS_BSD) $(SHAREDFLAGS) -o $(CODEC_LIB) $(CODEC_OBJS)


# Everything is rebuilt if this Makefile (which is hopefully named "Makefile") or any header changes.
$(OBJS): Makefile $(HEADERS)


$(CODEC_OBJS): Makefile $(CODEC_HEADERS)


# ----------------------------------------
# Misc. PHONY rules
# ----------------------------------------

# Cleanup
clean:
        rm -f $(PROG) *.a *.so *.o *~ *.core core


# Emacs etags
etags:
        etags `$(ETAGS_ARGS)`


# Print dependencies
dep: deps
deps:
        gcc -MM *.c


# Print make's internal database
print: printdb
printdb:
        make -p -f /dev/null


# Print predefined cpp macros
cpp:   macros
macro: macros
macros:
        @echo | cpp -dM


.PHONY: all clean

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Last modified: Thu Jul 2 16:04:09 CEST 2009