(Strange) C++ linker error in constructor
- by Microkernel
I am trying to write a template class in C++ and getting this strange linker error and can't figureout the cause, please let me know whats wrong with this!
Here is the error message I am getting in Visula C++ 2010.
1>------ Rebuild All started: Project: FlashEmulatorTemplates, Configuration: Debug Win32 ------
1> main.cpp
1> emulator.cpp
1> Generating Code...
1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall flash_emulator<char>::flash_emulator<char>(char const *,struct FLASH_PROPERTIES *)" (??0?$flash_emulator@D@@QAE@PBDPAUFLASH_PROPERTIES@@@Z) referenced in function _main
1>C:\Projects\FlashEmulator_templates\VS\FlashEmulatorTemplates\Debug\FlashEmulatorTemplates.exe : fatal error LNK1120: 1 unresolved externals
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========
Error message in g++
main.cpp: In function âint main()â:
main.cpp:8: warning: deprecated conversion from string constant to âchar*â
/tmp/ccOJ8koe.o: In function `main':
main.cpp:(.text+0x21): undefined reference to `flash_emulator<char>::flash_emulator(char*, FLASH_PROPERTIES*)'
collect2: ld returned 1 exit status
There are 2 .cpp files and 1 header file, and I have given them below.
emulator.h
#ifndef __EMULATOR_H__
#define __EMULATOR_H__
typedef struct {
int property;
}FLASH_PROPERTIES ;
/* Flash emulation class */
template<class T>
class flash_emulator
{
private:
/* Private data */
int key;
public:
/* Constructor - Opens an existing flash by name flashName or creates one with
given FLASH_PROPERTIES if it doesn't exist */
flash_emulator( const char *flashName,
FLASH_PROPERTIES *properties );
/* Constructor - Opens an existing flash by name flashName or creates one with
given properties given in configFIleName */
flash_emulator<T>( char *flashName,
char *configFileName );
/* Destructor for the emulator */
~flash_emulator(){
}
};
#endif /* End of __EMULATOR_H__ */
emulator.cpp
#include <Windows.h>
#include "emulator.h"
using namespace std;
template<class T>flash_emulator<T>::flash_emulator( const char *flashName,
FLASH_PROPERTIES *properties )
{
return;
}
template<class T>flash_emulator<T>::flash_emulator(char *flashName,
char *configFileName)
{
return;
}
main.cpp
#include <Windows.h>
#include "emulator.h"
int main()
{
FLASH_PROPERTIES properties = {0};
flash_emulator<char> myEmulator("C:\newEMu.flash", &properties);
return 0;
}
