CODEWITHSUNDEEP
c++makefile
Susan
Susan

Reputation: 301

Makefile always recompiles

i am having a hard time with the Makefile below. It always recompiles because it is looking for the objects in "source/" instead of "objects/".

Since i did not write that Makefile and don't know what all those options mean i can't figure out how to tell it to look for the objects in the correct folder.

TITLE =example_title

SRC_DIR = source/
OBJ_DIR = objects/
OUTDIR = build/

SRC := $(wildcard **/*.cpp)
OBJ := $(patsubst source/%.cpp,%.o,$(SRC))
FP_OBJ := $(patsubst %,objects/%,$(OBJ))
LIB = $(wildcard *.a) $(wildcard **/*.a)

CC =g++
LD =g++
CC_FLAGS = -m32 -c -Wall -g -o 
EXECUTABLE = $(TITLE)
LD_FLAGS = -m32 -L/usr/lib32 -o $(OUTDIR)$(EXECUTABLE)

$(OUTDIR)$(EXECUTABLE) : $(OBJ)
  $(LD) $(LD_FLAGS) $(FP_OBJ) $(LIB)

$(OBJ) : $(SRC)
  $(CC) $(CC_FLAGS)$(OBJ_DIR)$@ $(SRC_DIR)$*.cpp 

$(TITLE).tar.gz : **/*.h **/*.cpp Makefile **/*.txt
  tar -czf $@ Makefile **/*.h **/*.cpp **/*.txt

dist: $(TITLE).tar.gz

all : $(OUTDIR)$(EXECUTABLE)

clean : 
  rm -f $(OBJ_DIR)*.o
  rm -f $(OUTDIR)$(EXECUTABLE) $(TITLE).tar.gz

Upvotes: 1

Views: 161

Answers (1)

Beta
Beta

Reputation: 99154

This should do it:

$(OUTDIR)$(EXECUTABLE) : $(FP_OBJ)
    $(LD) $(LD_FLAGS) $^ $(LIB)

$(FP_OBJ) : $(OBJ_DIR)%.o : $(SRC_DIR)%.cpp
    $(CC) $(CC_FLAGS) $@ $<

The basic problem was here:

$(OBJ) : $(SRC)
    $(CC) $(CC_FLAGS)$(OBJ_DIR)$@ $(SRC_DIR)$*.cpp

Apart from the fact that $(OBJ) : $(SRC) makes each object depend on all sources, this rule promises foo.o and delivers objects/foo.o. So every time through, Make saw that there was no foo.o, and duly tried to rebuild it and the executable that required it.

There are other problems with this makefile, like the sloppy wildcards and the obnoxious practice of including slashes in the directory names, but they're not so serious.

Upvotes: 1

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