linker problem with --wrap option

[nsrajanme]

Hi,

I have successfully written the wrapper function. When I try to compile that it gave a linker error.

Please consider the program:
main.cpp
--------

#include "Test.h"
#include <stdio.h>

extern "C"
{
void __wrap__ZN4Test5printEP8Unneeded(Unneeded* test)
{
printf("This is wrapper function\n");
}
}

int main(int argc, void** argv)
{
Test a;
Unneeded u;
a.print(&u);
}

Test.h
------
#ifndef TEST_H_
#define TEST_H_

#include "Unneeded.h"

class Test
{
public:
void print(Unneeded *junk);
};

Test.cpp
--------
#include <stdio.h>
#include "Test.h"

void Test::print(Unneeded *junk)
{
printf("This is real function\n");
junk->sprint();
}

Unneeded.h
----------
#ifndef UNNEEDED_H_
#define UNNEEDED_H_

class Unneeded
{
private:
int i;

public:
void sprint();
};

Unneeded.cpp
------------
#include "Unneeded.h"

void Unneeded::sprint()
{

}


i have given the linker option as below:
linkopt -Wl,--wrap=_ZN4Test5printEP8Unneeded

If i don't include Test.o and Unneeded.o to create the executable, it worked fine. If i include only the Test.o, the executable asks for the definition of sprint() function.
"Test.cpp:(.text+0x19): undefined reference to `Unneeded::sprint()'"

I am wondering that why it asks for the definition of sprint() function, as it won't be called any time (please see that it worked fine, if i don't include test.o and unneeded.o). I am building only the static binary. Please help me to resolve this issue

[clanmjc]

You are callings junk->sprint(); from Test which you are linking which is why you are receiving the error. If you removed that call from Test you would be ok.