Re: Template class Compile problem

Mark <>
Thu, 31 Jan 2008 01:01:23 -0800 (PST)
On Jan 31, 12:55 am, Mark <> wrote:

On Jan 31, 12:21 am, hyderabadblues <> wrote:

I have created a timer class which is a template, but when I tried to
to create an object , I am getting following compile time error

template<class T>class prefetcher_tclTimer
   typedef tVoid (T::*PMEMFUNC)();

      T* m_poClient; // Pointer to calling class
      PMEMFUNC m_pMemFunc;
      tU32 _u32Timeout;
      tU32 _u32TimerInterval;
      static void vOnTimeout( tPVoid arg );
      tclTrace *m_poTrace;

      // Public functions
      // connstructor / destructor
      prefetcher_tclTimer ( );
      ~prefetcher_tclTimer( );

      tBool Create( tU32 u32TimerMSec, tU32 u32TimerIntervalMSec,
                       T* _poClient, PMEMFUNC _pMemFunc );
      tBool bStart( );
      tBool bReset( );
      tBool bStop ( );


I have defined the function bStart as

tBool prefetcher_tclTimer::bStart( )
   tS32 s32RetVal;

   if( _phTimerHandle != INVALID_HANDLE )
      m_poTrace->vInfo(" prefetcher_tclTimer::bStart "):

      s32RetVal = s32TimerSetTime( _phTimerHandle, _u32Timeout,
                                        _u32TimerInterval );
      if( s32RetVal != OK )
         m_poTrace->vInfo("prefetcher_tclTimer::bStart( ), Timer Set
      m_poTrace->vInfo("prefetcher_tclTimer::bStart( ), Invalid Timer
      s32RetVal = FALSE;
   return (tBool)s32RetVal;


I am getting an error as when tried to to compile it, I am creating
the template object with parameter tclUsbDataBuffer

Error: L6218E: Undefined symbol
prefetcher_tclTimer<tclUsbDataBuffer>::bStart() (referred from

The simple answer is to put the entire function (including
definitions) in the .h file. There's a reason for this, but I'd
probably screw up the explanation quite horribly and you're better to
google it.

Actually, I'll give it a shot.

 prefetcher_tclTimer<tclUsbDataBuffer>::bStart() is declared in
your .h file, but never defined (for tclUsbDataBuffer). When the
compiler sees prefetcher_tclTimer<tclUsbDataBuffer>::bStart() for the
first time, it needs to find the templated definition for it, and then
generate a function specifically for tclUsbDataBuffer. However, since
the compiler only has a declaration and not a definition at this
point, it can't do that.

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