GCC: Undefined reference (Makefile issue)

Question

Trying to compile these files with gcc under Makefile rules. Running gcc / make on cygwin.

Here's the makefile:

CC = gcc
CFLAGS = -g -O2 -Wall -std=c99
OBJECTS = simulation.o element.o

simulation.exe : $(OBJECTS)
    $(CC) $(CFLAGS) -o simulation.exe $(OBJECTS) 

simulation.o : file_priorite.o element.o
    $(CC) $(CFLAGS) -c simulation.c

file_priorite.o: file_priorite.h element.o
    $(CC) $(CFLAGS) -c file_priorite.c

element.o : element.h
    $(CC) $(CFLAGS) -c element.c 

clean:
    rm -f *.o simulation.exe

And getting these errors:

CLEAN SUCCESSFUL (total time: 52ms)
gcc -g -O2 -Wall -std=c99 -c element.c 
gcc -g -O2 -Wall -std=c99 -c simulation.c
gcc -g -O2 -Wall -std=c99 -o simulation.exe simulation.o element.o 
simulation.o: In function `main':
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:11: undefined reference to `construire'
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:11:(.text.startup+0x17): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `construire'
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:20: undefined reference to `ajouter_element'
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:20:(.text.startup+0x69): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `ajouter_element'
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:23: undefined reference to `consommer_element'
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:23:(.text.startup+0x76): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `consommer_element'
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:23: undefined reference to `consommer_element'
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:23:(.text.startup+0x86): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `consommer_element'
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:25: undefined reference to `obtenir_taille'
/cygdrive/d/Dropbox/UQAM AUTOMNE 2014/INF7330/lab10/lab10/simulation.c:25:(.text.startup+0x96): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `obtenir_taille'
collect2: error: ld returned 1 exit status
Makefile:6: recipe for target 'simulation.exe' failed
make: *** [simulation.exe] Error 1

The problematic functions are all implemented in file_priorite.c .

Any idea?

Answer 1

你需要

OBJECTS = simulation.o element.o file_priorite.o

Answer 2

Notice that your build log doesn't include file_priorite in any form - that means you're not building/linking against it. Add file_priorite.o to your OBJECTS line.