Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!aplcen!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.std.c
Subject: Re: #ifdef
Keywords: preprocessor, inactive segments
Message-ID: <11753@smoke.BRL.MIL>
Date: 6 Dec 89 15:55:13 GMT
References: <9326@microsoft.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 17

In article <9326@microsoft.UUCP> azeemk@microsoft.UUCP (Azeem Kahn) writes:
-#else
-/*
-#endif
-*/
-#endif
-VAR is defined and hence the #else is the inactive segment. Now
-should the preprocessor match the #else with the first or the
-second #endif? In other words, does the preprocessor have to look
-at the lines in the inactive segment for comments, unclosed qoutes
-etc. OR should it disregard everything in the inactive segment and
-just keep looking for a matching #endif to satisfy the nesting.

This is answered in section 2.1.1.2, "Translation phases".
Comments are replaced by spaces before preprocessing directives
are executed.
Thus there is no "first #endif"; it is commented-out.