virutal function in static library

[pipehappy]

Hi there,

I have came across a problem to make a library with virtual function.
I have example code listed below and if I compile this way it works:
g++ main.cpp a.cpp -o main
But when I want to have a static library it reports error:
g++ -c a.cpp -o liba.o
ar rcs liba.a liba.o
g++ -L. -la main.cpp -o main
/tmp/ccqQZO7f.o.rodata._ZTV4Base[vtable for Base]+0x10): undefined
reference to `__cxa_pure_virtual'

Anyone has any suggestion about this?

Thx

Here is the code example:

a.h:

#ifndef HE
#define HE
class Base {
public:
virtual double func(double)=0;
};

class Child: public Base{
public:
virtual double func(double);
};
#endif


a.cpp:

#include "a.h"

double Child::func(double a) {
return a+ 3;
}


main.cpp:

#include "a.h"

int
main (void) {
Child child1;
child1.func(0.3);
}

 

[Ian Collins]

Hi there,

I have came across a problem to make a library with virtual function.
I have example code listed below and if I compile this way it works:
g++ main.cpp a.cpp -o main
But when I want to have a static library it reports error:
g++ -c a.cpp -o liba.o
ar rcs liba.a liba.o
g++ -L. -la main.cpp -o main
/tmp/ccqQZO7f.o.rodata._ZTV4Base[vtable for Base]+0x10): undefined
reference to `__cxa_pure_virtual'

This is a tool question, rather than a C++ one.

Anyone has any suggestion about this?

Link in the correct order!

g++ -L. main.cpp -la -o main

 

[pipehappy]

Hi there,

I have came across a problem to make a library with virtual function.
I have example code listed below and if I compile this way it works:
g++ main.cpp a.cpp -o main
But when I want to have a static library it reports error:
g++ -c a.cpp -o liba.o
ar rcs liba.a liba.o
g++ -L. -la main.cpp -o main
/tmp/ccqQZO7f.o.rodata._ZTV4Base[vtable for Base]+0x10): undefined
reference to `__cxa_pure_virtual'

This is a tool question, rather than a C++ one.

Anyone has any suggestion about this?

Thx for quick reply.
Link in the correct order!

g++ -L. main.cpp -la -o main