what‘s wrong with my makefile

mzzz (33)
recently, i am learning how to write a makefile on linux.
now, i give my source files and returned mistakes:
f1.h
 
 
void f1();

f1.c
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#include "f1.h"
#include <stdio.h>
void f1(){
  printf("this is function f1\n");
}

f2.h
 
 
void f2();

f2.c
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#include "f2.h"
#include <stdio.h>
void f2(){
  printf("this is function f2\n");
}

main.c
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#include "f1.h"
#include "f2.h"
#include <stdio.h>
int main(){
  f1();
  f2();
  puts("Press any key to continue...");
  getchar();
  return 0;
}

the follows is my makefile:
makefile
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#this is my first makefile
main:main.o f1.o f2.o
	gcc -o main main.o f1.o f2.o
main.o:f1.h f2.h
	gcc -C main.c
f1.o:f1.h
	gcc -C f1.c
f2.o:f2.h
	gcc -C f2.c
.PHONY:clean
	rm main main.o f1.o f2.o


////////////////////////////////////
when i enter "make" command in terminal, it returns:

gcc -C f1.c
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 0 has invalid symbol index 11
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 1 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 2 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 3 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 4 has invalid symbol index 11
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 5 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 6 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 7 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 8 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 9 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 10 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 11 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 12 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 13 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 14 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 15 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 16 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 17 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 18 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 19 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 20 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info): relocation 21 has invalid symbol index 22
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_line): relocation 0 has invalid symbol index 2
/usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crt1.o: In function `_start':
(.text+0x18): undefined reference to `main'
collect2: error: ld returned 1 exit status
make: *** [f1.o] Error 1


i am confuse what is wrong with my makefile?

Any kindly advice would be help.
thinks~




Last edited on
ne555 (10692)
it should be -c (lowercase) to just compile
kbw (9488)
You don't need mention the compiler at all.
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PROG = main
SRCS = main.c f1.c f2.c

.PHONEY: clean

all: $(PROG)

clean:
        - rm $(PROG) $(SRCS:.c=.o)

$(PROG): $(SRCS:.c=.o)

f1.o: f1.h

f2.o: f2.h

main.o: f1.h f2.h
Last edited on
mzzz (33)
@ne55
think you very much. i have tried as your suggestion, and it works. you have a good eyesight.
@kbw
i kinda new to writing makefile, so i don't understand your writing type. i need to learn more deep. but also think you very much.
kbw (9488)
The idea is that GNU make knows how to compile and link a C program already, you just need to supply the dependencies.

Lines 1 - 9 should be clear, except $(SRCS:.c=.o). That means take all files that end with .c and replace the extension with .o. It's the list of object files.

Line 11: prog depends on .o files. GNU make knows how to create a .o file from a .c file, and it knows how to create a program from a list of .o files, so you don't need to specify it.

Lines 13-17 should be clear as well, they're header file dependencies.
Last edited on
mzzz (33)
@kbw
thanks, your explain is very clear, i can understand it.
i have learned a method to creat *.o file from *.c

OBJ=$(patsubst %.c,%.o,$(wildcard *.c))
main:$(OBJ)
	gcc -o main $(OBJ)


do those two styles have some differences?
Last edited on
kbw (9488)
The version I use is simpler. It's what GNU make call Substitution References.
https://www.gnu.org/software/make/manual/html_node/Substitution-Refs.html#Substitution-Refs

To quote https://www.gnu.org/software/make/manual/html_node/Text-Functions.html
Substitution references (see Substitution References) are a simpler way to get the effect of the patsubst function:

$(var:pattern=replacement)

is equivalent to

$(patsubst pattern,replacement,$(var))
Last edited on
mzzz (33)
@kbw
thinks for your kindness. i get it.
and think you again
Last edited on
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