VPATH not seems to be working

[Guest olaoni]

To Whom It May Concern,

 

I am trying to learn the usage of VPATH in a makefile, but does not seems to be working for me. I am sure I am doing something wrong and hoping that someone would point this out to me

 

I have the following makefile named Makefile

 

################MAKEFILE##################

#INCLUDE = /path/to/the/general.h

INCLUDE = ./inc

 

VPATH = ./src:./inc

 

obj=$(patsubst %.c,%.o,$(wildcard *.c))

 

main: $(obj) general.h

gcc -g -o $@ $^ -I$(INCLUDE)

 

%.o: %.c

gcc -g -c -o $@ $< -I$(INCLUDE)

 

clean:

rm -r *.o main

 

######### END OF MAKEFILE #####################

 

############ main.c #######################

 

#include <stdio.h>

#include <general.h>

 

int main(int argc, char** argv)

{

print_foo();

print_bar();

 

return 0;

}

 

############ end main.c #######################.

 

########### bar.c ######################

 

#include <general.h>

 

void print_bar(void)

{

printf("Hello bar.\n");

}

 

######### end of bar.c ###############

 

############# foo.c ###############

#include <general.h>

 

void print_foo(void)

{

printf("Hello foo.\n");

}

 

############ end of foo.c ############

 

########### general.h ####################

#ifndef GENERAL_H

#define GENERAL_H

 

#include <stdio.h>

 

void print_foo(void);

void print_bar(void);

 

#endif

 

########### end of general.h ##############

 

Below is the tree directory structure in the file system

 

Code:

.

├── inc

│ └── general.h

├── main.c

├── main.o

├── Makefile

└── src

├── bar.c

└── foo.c

My understanding that make will search the path assigned to the VPATH variables hence "src" and "inc" in this case but when I build it get the following linker error.

 

############# OUTPUT ################

gcc -g -o main main.o -I./inc

main.o: In function `main':

/home/olaoni/devl/make-tutor/main.c:5: undefined reference to `print_foo'

/home/olaoni/devl/make-tutor/main.c:6: undefined reference to `print_bar'

collect2: error: ld returned 1 exit status

make: *** [main] Error 1

#####################################

 

Many thanks in advance.

 

Regards

 

onio

 

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