parsing the format string at compile time...

[david richard cook]

>From article <705 at nixbur.UUCP>, by jobrien at nixbur.UUCP (John O'Brien):
> printf call is a constant (which it is most of the time), the compiler
> should be able to parse the string at compile time, and turn the printf
> call into something like the series of Modula-2 calls, with a correspond-
> ing increase in efficiency.  Do C compilers do this?  Are there any prob-
> lems with doing this?
> 
> 				Enquiring Minds Want to Know!
> 

	If C did allow this, it would not be C.  The compiler knows
nothing about any functions, including I/O.  Some new compilers may be
able to this, though I do not know of any, by using the #pragma
preprocesser directive to declare certain functions as builtin.  The
use of #pragma is left up to the compiler implementation and not C.
If an ANSI C implementation does not understand what the #pragma
directive is trying to accomplish, it will simply ignore it.