undefined reference to base constructor

Question

Possible Duplicate:
“undefined reference to” in G++ Cpp

I have this header

#ifndef TEST_H_
#define TEST_H_

class TEST
{
public :
    TEST();
};


#endif /* TEST_H_ */

and this header

#ifndef TESTS_H_
#define TESTS_H_
#include "TEST.h"

class TESTS : public TEST
{
public :
    TESTS();
};


#endif /* TESTS_H_ */

I implemented those header like this:

#include <iostream>
using namespace std;
#include "TEST.h"
TEST:: TEST()
{
}
int main(int argc, char **argv) {
    return 0;
}

and this:

#include "TESTS.h"

TESTS :: TESTS() : TEST()
{
}


int main(int argc, char **argv) {
    return 0;
}

and I get the follwing error:

/tmp/cc4jN1HN.o: In function TESTS::TESTS()': TESTS.cpp:(.text+0xd): undefined reference toTEST::TEST()'

Why is it ?

What am I doing wrong ?

You can't ask us what you're doing wrong if you don't tell us what you're *trying* to do! And it's far from clear: Why do you have two `main` functions?! A program can only have one. Is this supposed to be two programs or one program? — David Schwartz, Dec 31 '12 at 08:40

score 6 · Answer 1 · answered Dec 31 '12 at 08:39

6

This is a linker error. You're probably not compiling and linking all the required files. It should be e.g.:

$ g++ -Wall TEST.cpp TESTS.cpp -o TEST

You also need to get rid of one of the main() functions.

answered Dec 31 '12 at 08:39

Paul R

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Thank you both !!! It help me . and I delete one of the main. – John Oldman Dec 31 '12 at 08:44

score 1 · Answer 2 · answered Dec 31 '12 at 08:42

1

If this is supposed to be one program, it can only have one main function. If this is supposed to be two programs, then the one with TESTS::TESTS in it also needs the constructor for TEST.

answered Dec 31 '12 at 08:42

David Schwartz

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score 0 · Answer 3 · answered Dec 31 '12 at 08:40

Assuming your two .cpp files are named TEST.cpp and TESTS.cpp, I'm guessing you're just compiling the first one, such as with

g++ TESTS.cpp

but you need to compile them both together, such as with

g++ TEST.cpp TESTS.cpp

otherwise, TESTS.cpp won't be able to find the code defined in TEST.cpp when it's compiling.

undefined reference to base constructor

3 Answers3