===================================================================
@@ -948,7 +948,7 @@ twice.
CPP optimizes even further. It remembers when a header file has a
wrapper @samp{#ifndef}. If a subsequent @samp{#include} specifies that
header, and the macro in the @samp{#ifndef} is still defined, it does
-not bother to rescan the file at all.
+not bother to open the file at all.
You can put comments outside the wrapper. They will not interfere with
this optimization.
@@ -968,7 +968,8 @@ additional text, to avoid conflicts with
CPP supports two more ways of indicating that a header file should be
read only once. Neither one is as portable as a wrapper @samp{#ifndef}
and we recommend you do not use them in new programs, with the caveat
-that @samp{#import} is standard practice in Objective-C.
+that @samp{#import} is standard practice in Objective-C. Note that CPP
+optimizations obviate the need for these methods.
@findex #import
CPP supports a variant of @samp{#include} called @samp{#import} which
@@ -992,7 +993,8 @@ prevent the file from ever being read ag
Another way to prevent a header file from being included more than once
is with the @samp{#pragma once} directive. If @samp{#pragma once} is
seen when scanning a header file, that file will never be read again, no
-matter what.
+matter what. (Note that @samp{#pragma once} is obsolete due to CPP
+optimizations and its use should be eliminated from GNU source files.)
@samp{#pragma once} does not have the problems that @samp{#import} does,
but it is not recognized by all preprocessors, so you cannot rely on it