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From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: parsing the format string at compile time...
Keywords: format printf parsing modula-2
Message-ID: <11262@smoke.BRL.MIL>
Date: 12 Oct 89 01:42:58 GMT
References: <705@nixbur.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 11

In article <705@nixbur.UUCP> jobrien@nixbur.UUCP (John O'Brien) writes:
-It seems to me that if the format string in the 
-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?

The proposed C Standard permits this in a conforming hosted implementation.
I don't know of any existing implementations that do this, although some do
optimize other standard library functions into in-line code.