Re[2]: Eliminate Function Call in Conditional Macro

[Shigeru Mabuchi]

Hi James,

PORTER, JAMES C (Jim), ALBAS wrote in RE: Eliminate Function Call in 
Conditional Macro:

>This is from the IBM Open Class Library, which is trying to do the same 
>technique...
>
>#ifdef IC_TRACE_RUNTIME
>   #define ITRACE_RUNTIME(p1)          ITrace::write(p1)
>#else
>   #define ITRACE_RUNTIME(p1)
>#endif
>
>The difference is -- you need to include the parameter in the #define 
>variable, so that the parameter is part of the definition.

 Yes, but this only works with fixed arguments.
 In my Trace function, I use flexible number of arguments,
like printf.
 
void CProcess::Trace(LPCSTR format, ...)
{
#ifdef _TRACE
        va_list args;
        va_start(args,format);
        ..all the printing...
        va_end(args);
#endif
}

 Although I can filter the printing by including the
above condition inside the Trace function,
a call like

  TRACE("info is %d,%d\n",getinfo(x),getinfo(y));

will still do some extra work by calling getinfo().

The easiest way might be to write it as:

#ifdef _TRACE
  Trace("info is %d,%d\n",getinfo(x),getinfo(y));
#endif

 But this is what I am trying to avoid for better 
legibility and less redundancy.

 Sorry if I'm asking too much. :-)

Regards,
S. Mabuchi
WING
http://www.wing.gr.jp/