I am having issue getting my makefile to work without errors. The first issue i have is with an undefined reference to main. I have main in my producer.c file as a function. The second issue is an undefined reference to SearchCustomer().
error:
bash-4.1$ make
gcc -Wall -c producer.c shared.h
gcc -Wall -c consumer.c shared.h
gcc -Wall -c AddRemove.c shared.h
gcc -pthread -Wall -o producer.o consumer.o AddRemove.o
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../lib64/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
AddRemove.o: In function `AddRemove':
AddRemove.c:(.text+0xb1): undefined reference to `SearchCustomer'
AddRemove.c:(.text+0x1e9): undefined reference to `SearchCustomer'
AddRemove.c:(.text+0x351): undefined reference to `SearchCustomer'
collect2: ld returned 1 exit status
make: *** [producer] Error 1
makefile:
COMPILER = gcc
CCFLAGS = -Wall
all: main
debug:
make DEBUG=TRUE
main: producer.o consumer.o AddRemove.o
$(COMPILER) -pthread $(CCFLAGS) -o producer.o consumer.o AddRemove.o
producer.o: producer.c shared.h
$(COMPILER) $(CCFLAGS) -c producer.c shared.h
consumer.o: consumer.c shared.h
$(COMPILER) $(CCFLAGS) -c consumer.c shared.h
AddRemove.o: AddRemove.c shared.h
$(COMPILER) $(CCFLAGS) -c AddRemove.c shared.h
ifeq ($(DEBUG), TRUE)
CCFLAGS += -g
endif
clean:
rm -f *.o
This question is related to
c
gcc
compilation
compiler-errors
makefile
This error means that, while linking, compiler is not able to find the definition of main()
function anywhere.
In your makefile, the main
rule will expand to something like this.
main: producer.o consumer.o AddRemove.o
gcc -pthread -Wall -o producer.o consumer.o AddRemove.o
As per the gcc
manual page, the use of -o
switch is as below
-o file Place output in file file. This applies regardless to whatever sort of output is being produced, whether it be an executable file, an object file, an assembler file or preprocessed C code. If
-o
is not specified, the default is to put an executable file ina.out
.
It means, gcc will put the output in the filename provided immediate next to -o
switch. So, here instead of linking all the .o
files together and creating the binary [main
, in your case], its creating the binary as producer.o
, linking the other .o
files. Please correct that.
Source: Stackoverflow.com