CODEWITHSUNDEEP
makefilegnu-make
Aman Sharma
Aman Sharma

Reputation: 119

Make compiling a file two times

I have my .c and .o files in different directory. My make file look like this

CC = cc
SRCDIR = src
OBJDIR = bin
TARGET = main # output binary
# do not edit below this line
SOURCES = $(shell find $(SRCDIR) -type f -name *.c)
OBJECTS = $(patsubst $(SRCDIR)/%,$(OBJDIR)/%,$(SOURCES:.c=.o))
#Flags, Libraries
CFLAGS      := -I. -c 
LIB         := 

all: $(OBJECTS)
    $(CC) $(OBJECTS) -o $(TARGET)

$(OBJECTS):$(SOURCES)
    $(CC) $(CFLAGS) $< $(LIB) -o $@

.PHONY : clean

clean:
    rm bin/*
    rm main

But when I run it. it somehow manages to compile a file two time.

make
cc -I. -c  src/somefile.c  -o bin/somefile.o
cc -I. -c  src/somefile.c  -o bin/main.o
cc bin/somefile.o bin/main.o -o main 
/usr/bin/ld: /usr/lib/gcc/x86_64-redhat-linux/10/../../../../lib64/crt1.o: in function `_start':
(.text+0x24): undefined reference to `main'
collect2: error: ld returned 1 exit status

Upvotes: 2

Views: 172

Answers (2)

Maxim Egorushkin
Maxim Egorushkin

Reputation: 136256

The pattern rules need fixes:

all: $(TARGET)

$(TARGET): $(OBJECTS)
    $(CC) -o $@ $^ $(LIB)

$(OBJDIR)/%.o : $(SRCDIR)/%.c | $(OBJDIR)
    $(CC) -o $@ -c $(CFLAGS) $<

$(OBJDIR) :
    mkdir -p $@

.PHONY : all

You also need automatic dependency generation.

Upvotes: 1

tripleee
tripleee

Reputation: 189397

Your $(OBJECTS) recipe is literally asking it to compile $< which is the first file in $(SOURCES).

Probably simply remove these recipes; make already knows exactly how to compile C files correctly.

Upvotes: 0

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