Why this makefile is always recompiling? - c++

Question

I've done a makefile for a project I'm working on andd my code is allways getting recompiled, and I don't know why... I've tried adding the .PHONY to the all target but didn't work. Here is the makefile:
TARGET = csv2sqlite
CXX = g++
CXXFLAGS = -std=c++11 -Wall -I $(INCDIR) -fdiagnostics-color=always -D_DEBUG
OBJECTS = csv.o main.o
BINDIR = bin
OBJDIR = obj
INCDIR = inc
SRCDIR = src
.PHONY:default
default: $(OBJECTS) $(TARGET)
%.o: $(SRCDIR)/%.cpp
#echo "Compiling dependecies..."
$(CXX) $(CXXFLAGS) -c $< -o $(OBJDIR)/$#
#echo "Done compiling $#"
$(TARGET): $(addprefix $(OBJDIR)/, $(OBJECTS))
#echo "Linking $# file..."
$(CXX) $(CXXFLAGS) $^ -o $(BINDIR)/$#
#echo "Linking $# file..."
run:
bin/$(TARGET)
clean:
rm -f obj/* bin/$(TARGET)
And the directory tree is:
project
├── inc
│ └── csv.hpp
├── src
│ ├── csv.cpp
│ └── main.cpp
├── obj
│ ├── csv.o
│ └── main.o
├── bin
│ └── csv2sqlite
└── makefile
Here is the complete project if you wanna see it. Also, what kind of improves I can do it?
Thanks!

Answer 1

Here:
%.o: $(SRCDIR)/%.cpp
...
$(CXX) $(CXXFLAGS) -c $< -o $(OBJDIR)/$#
#echo "Done compiling $#"
No, you're not. You didn't build foo.o, you built obj/foo.o, so the next time you tell Make to build foo.o, it will see that foo.o does not exist and attempt to rebuild it-- with this rule, which doesn't do what it claims to do. Likewise:
$(TARGET): $(addprefix $(OBJDIR)/, $(OBJECTS))
#echo "Linking $# file..."
$(CXX) $(CXXFLAGS) $^ -o $(BINDIR)/$#
#echo "Linking $# file..."
This doesn't build $(TARGET), it builds $(BINDIR)/$(TARGET), so Make runs this rule every time it's told to build $(TARGET).
The fix is simple:
OBJECTS = $(addprefix $(OBJDIR)/, csv.o main.o)
$(OBJDIR)/%.o: $(SRCDIR)/%.cpp
...
$(CXX) $(CXXFLAGS) -c $< -o $#
#echo "Done compiling $#"
TARGET = $(BINDIR)/csv2sqlite
$(TARGET): $(OBJECTS)
#echo "Linking $# file..."
$(CXX) $(CXXFLAGS) $^ -o $#
#echo "Linking $# file..."