Makefiles

Makefiles are very useful to automate compilation of multi-file projects in c/c++ with Linux.

• variables:

<VARIABLE>=<string> # init
$(<VARIABLE>)       # get content

• targets:

<target>: <prerequisite-targets>
	<code-to-execute>

• template targets:

%.o:%.cpp
	<code-to-execute>

• automatic variables (complete list)::
  • $@ : target
  • $^ : list of requirements
  • $< : first requirement
  • $(MAKECMDGOALS) : make argument

• functions (complete list):
  • $(subst from,to,text)
  • $(filter-out <list>, <list>)

• Mini Example

COMPILO=g++
SRCSCPP = $(wildcard src/*.cpp)
OBJS = $(patsubst %.cpp,build/%.o,$(notdir $(SRCSCPP)))
prog: $(OBJS)
	$(COMPILO) -o build/$@ $(OBJS)
build/%.o:%.cpp
	$(COMPILO) -c -o $@ $^

INCLUDE= \
	-I/usr/include \
	-I/usr/local/include \
	-I. \
	`pkg-config --cflags libglade-2.0` 
 
BIN_PATH=./
 
LIBS= \
	`pkg-config --libs libglade-2.0` \
	`pkg-config --libs gtk+-2.0` \
	-export-dynamic
 
LIBS_PATH= \
	-L/lib \
	-L/usr/lib \
	-L/usr/local/lib \
	-L.
 
COMPILO=g++
 
FLAGS= -c -g -Wall -ansi -pedantic
#FLAGS= -c -ansi -pedantic
 
OBJ= \
	file1.o \
	file2.o
 
 
 
 
# cibles :
 
monprog: $(OBJ)
	$(COMPILO) -o $(BIN_PATH)monprog $(OBJ) $(LIBS_PATH) $(LIBS)
 
clean : 
	rm -f *.o
 
clear : 
	rm -f *.o monprog
 
# compilation des sources :
 
file1.o : file1.cpp file1.h
	$(COMPILO) $(FLAGS) $(INCLUDE) -o file1.o file1.cpp
 
file2.o : file2.cpp file2.h
	$(COMPILO) $(FLAGS) $(INCLUDE) -o file2.o file2.cpp

When using libraries, pkg-config is very useful :

pkg-config --cflags libxml++-2.6
pkg-config --libs libxml++-2.6