C ++编译错误-未定义参考

Question

I'm having a bit of trouble trying to compile the following simple code in cygwin:

main.cpp:

#include <iostream>
#include "Point.h"

using namespace std;

int main() {
    Point a;
    return 0;
}

Point.cpp:

#include <iostream>
#include "Point.h"

using namespace std;

Point::Point() {
    cout << "Compile test" << endl;
}

Point.h:

#ifndef POINT_H
#define POINT_H

class Point {
    public:
        Point();
};

#endif

Make file:

CC=g++
CFLAGS=-c -Wall
LDFLAGS=
SOURCES=main.cpp Point.cpp
OBJECTS=$(SOURCES:.cpp=.o)
EXECUTABLE=test

all: $(SOURCES) $(EXECUTABLE)

$(EXECUTABLE): $(OBJECTS)
    $(CC) $(LDFLAGS) $(OBJECTS) -o $@

%.o : %.cpp
    $(CC) $(CFLAGS) -c $<

clean:
    rm -rf *.o core

When I try to compile main.cpp, I'm getting the following error:

main.o:main.cpp:(.text+0x15): undefined reference to `Point::Point()'
main.o:main.cpp:(.text+0x15): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `Point::Point()'

And when I try to compile Point.cpp, I'm getting:

/usr/lib/gcc/x86_64-pc-cygwin/4.9.3/../../../../lib/libcygwin.a(libcmain.o): In function `main':
/usr/src/debug/cygwin-2.2.1-1/winsup/cygwin/lib/libcmain.c:39: undefined reference to `WinMain'
/usr/src/debug/cygwin-2.2.1-1/winsup/cygwin/lib/libcmain.c:39:(.text.startup+0x7f): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `WinMain'

All files are in the same directory. I should also note that the main class compiles perfectly fine if I don't create the point object. Any ideas? Would really appreciate some help, thanks!

Answer 1

(Reposting from comments since this turned out to solve it)

So, my assumption is that your build system is messed up, and you aren't actually compiling Point.cpp .

You can check if you are or not by looking at what gets printed in the console when you use make VERBOSE=1 , more info here:

How do I force make/gcc to show me the commands?

Answer 2

I get the same undefined reference to `WinMain' problem when I forget the executable name for the linking.

g++ -o source1.o source2.o

instead of

g++ -o executable source1.o source2.o

I did not find the answer anywhere for my problem so I hope it helps...