Pure virtual classes and the error undefined reference to `vtable

Question

I'm trying to implement a pure virtual class and derived class, but I am getting the following error.

    /usr/lib64/gcc/x86_64-suse-linux/8/../../../../x86_64-suse-linux/bin/ld: /tmp/ccvROhIa.o: in function `main':
main.cpp:(.text+0x1ea): undefined reference to `vtable for bca2016_vol1_amdt1'
/usr/lib64/gcc/x86_64-suse-linux/8/../../../../x86_64-suse-linux/bin/ld: /tmp/ccvROhIa.o: in function `bca2016_vol1_amdt1::~bca2016_vol1_amdt1()':
main.cpp:(.text._ZN18bca2016_vol1_amdt1D2Ev[_ZN18bca2016_vol1_amdt1D5Ev]+0xd): undefined reference to `vtable for bca2016_vol1_amdt1'
collect2: error: ld returned 1 exit status

I'm still new to c++, so I'm trying to learn what's wrong and why it's wrong. From my research it seems like it's primarily to do with the linker and the most common reason for this is that a virtual function hasn't been declared or that a virtual destructor hasn't been declared, though i'm pretty sure I have declared it?

I looked up your error, it produced https://stackoverflow.com/questions/3065154/undefined-reference-to-vtable - Did you come upon it while researching your issue? — StoryTeller - Unslander Monica, Oct 04 '18 at 13:22
Yeah i've read that link, however I believe i've defined all of my non pure functions...as far as I know (still very new) — user1406186, Oct 04 '18 at 13:24
There's a fair few answers there with common gotcha's, tried them all? — StoryTeller - Unslander Monica, Oct 04 '18 at 13:25
There are **pure virtual functions** and **abstract classes**. There is no such thing as a "pure virtual class". An abstract class has one or more pure virtual functions. — Pete Becker, Oct 04 '18 at 13:31

Maxim Egorushkin · Accepted Answer · 2018-10-04T13:32:35.350

2

In file bca2016_vol1_amdt1.cpp you use wrong class name bca (thus providing implementations for pure virtual functions of class bca, which is well formed). It should be bca2016_vol1_amdt1.

Also, bca2016_vol1_amdt1.cpp must include bca2016_vol1_amdt1.h.

edited Oct 04 '18 at 13:32

answered Oct 04 '18 at 13:25

Maxim Egorushkin

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Thanks, i've been staring at this for so long that I didn't even realise... – user1406186 Oct 04 '18 at 13:30

Pure virtual classes and the error undefined reference to `vtable

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