2004-01-12  Stepan Kasal  <address@hidden>

	* standards.texi (POSIX_ONLY): New environment variable.
	  (POSIXLY_CORRECT): Explain the difference.

--- standards.texi.orig	2004-01-12 08:45:55.000000000 +0100
+++ standards.texi	2004-01-12 09:08:19.000000000 +0100
@@ -349,7 +349,19 @@
 Many GNU programs suppress extensions that conflict with @sc{posix} if the
 environment variable @code{POSIXLY_CORRECT} is defined (even if it is
 defined with a null value).  Please make your program recognize this
-variable if appropriate.
+variable if appropriate.  (If your program recognizes the @samp{--posix}
+option, it should give the same behavior as if @code{POSIXLY_CORRECT}
+were set.)
+
address@hidden @code{POSIX_ONLY}, environment variable
+On the other hand, if the program is a basic tool, it might be useful to
+suppress @emph{all extensions}, not only the conflicting ones, in order
+to debug a @sc{posix}-portable script which calls the tool.
+This should be done via the environment variable @code{POSIX_ONLY}.
+If it is defined (even if it has a null value), the program should do
+it's best to provide a minimal feature set required by @sc{posix}.
+Please make your program recognize this variable too, if appropriate.
+(It doesn't seem necessary to create an equivalent option.)
 
 When a feature is used only by users (not by programs or command
 files), and it is done poorly in Unix, feel free to replace it
@@ -1722,7 +1734,8 @@
 @samp{-c} in @code{cpio} and @code{tar}.
 
 @item posix
-Used in @code{gawk}.
+Suppress extensions which conflict with @sc{posix}; used eg.@ in @code{gawk}.
address@hidden, for a detailed explanation.
 
 @item prefix-builtins
 @samp{-P} in @code{m4}.