post  collect2 error

devas (6)   Link to this post
Hello,

i'm trying to call a C method in C++ code and i have some difficulties about it.

let me explain it with code samples:


my .h header file.
#ifndef X_MODULE_H_
#define X_MODULE_H_

#include <stdio.h>
#ifdef __cplusplus
extern "C"
{
#endif

int printStatus();

#ifdef __cplusplus
}
#endif
#endif /*X_MODULE_H_*/

my .c implementation file
#include "X_Module.h"

int printStatus()
{
printf("printStatus is called\n");
return 1;
}

my main.cpp file
#include <iostream>
using namespace std;
extern "C"
{
#include "/home/user/sample/X_Module/X_Module_Module.h"
}

int main()
{

printStatus();
return 0;
}

now, firstly i compiled the c code which is located at X_Module folder
user@user-desktop:~/sample$ ls
user@user-desktop:~/sample/X_Module$ ls
X_Module.c X_Module.h X_Module.o Makefile
user@user-desktop:~/sample/X_Module$

then i compiled the sample folder.
X_Module main.o
main.cpp Makefile
user@user-desktop:~/sample$

Here is the Makefiles:

This is the X_Module's Makefile:
SRCS = X_Module.c

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

CCOPTS = -Wall -g -O2

.c.o : $(CCOPTS)
$(CC) -c $<

all: $(OBJS)

clean:
rm -f *.o *~

This is the main's Makefile:
SYSDEF = TGS

LIBDIR = /usr/lib

CXXFLAGS = -Wall -g -O2 \
-DCMP_KUS \
-DCMP_RFM1G -DDEBUG

CFLAGS = -g -O2 \
-DCMP_RFM2G -DDEBUG -DLINUX -DCMP_$(SYSDEF)

LFLAGS = -lpthread -lexpat -lxerces-c -lvmic -L$(LIBDIR)/rfm2g -lrfm2g

CXXSRCS = main.cpp

CSRCS = /home/user/sample/X_Module/X_Module.c

CXXOBJS = $(CXXSRCS:.cpp=.o)
COBS = $(CSRCS:.c=.o)

all: sample

sample: ${COBJS} ${CXXOBJS}
${CXX} ${COBJS} ${CXXOBJS} -o sample ${LFLAGS}

clean:
rm -f sample ${COBJS} ${CXXOBJS}

dep:
${CXX} ${CXXFLAGS} -MM ${CXXSRCS} > .depends
${CC} ${CFLAGS} -MM ${CSRCS} >> .depends

include .depends

when i try to compile main, i'm getting this error:
user@user-desktop:~/sample$ touch .depends
user@user-desktop:~/sample$ make dep
g++ -Wall -g -O2 -DCMP_KUS -DCMP_RFM1G -DDEBUG -MM main.cpp > .depends
cc -g -O2 -DCMP_RFM2G -DDEBUG -DLINUX -DCMP_TGS -MM /home/user/sample/X_Module/X_Module.c >> .depends
user@user-desktop:~/sample$ make all
g++ -Wall -g -O2 -DCMP_KUS -DCMP_RFM1G -DDEBUG -c -o main.o main.cpp
g++ main.o -o sample -lpthread -lexpat -lxerces-c -lvmic -L/usr/lib/rfm2g -lrfm2g
main.o: In function `main':
/home/user/sample/main.cpp:22: undefined reference to `printStatus'
collect2: ld returned 1 exit status
make: *** [sample] Error 1
user@user-desktop:~/sample$

Do you have any idea why i'm getting this error?
jsmith (3794)   Link to this post
I do not see you linking against X_Module.o which contains the implementation of printStatus.

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