Changes to m4/doc/m4.texinfo,v [branch-1_4]

[Eric Blake]

CVSROOT:        /sources/m4
Module name:    m4
Branch:         branch-1_4
Changes by:     Eric Blake <ericb>      07/08/10 15:13:02

Index: doc/m4.texinfo
===================================================================
RCS file: /sources/m4/m4/doc/m4.texinfo,v
retrieving revision 1.1.1.1.2.134
retrieving revision 1.1.1.1.2.135
diff -u -b -r1.1.1.1.2.134 -r1.1.1.1.2.135
--- doc/m4.texinfo      10 Aug 2007 13:01:22 -0000      1.1.1.1.2.134
+++ doc/m4.texinfo      10 Aug 2007 15:13:02 -0000      1.1.1.1.2.135
@@ -5723,9 +5723,10 @@
 exact output of @code{errprint} is not very portable to other @code{m4}
 implementations: @acronym{POSIX} requires that all arguments be printed,
 but some implementations of @code{m4} only print the first.
-Furthermore, some BSD implementations always append a newline for each
address@hidden call, regardless of whether the last argument already
-had one, and @acronym{POSIX} is silent on whether this is acceptable.
+Furthermore, some @acronym{BSD} implementations always append a newline
+for each @code{errprint} call, regardless of whether the last argument
+already had one, and @acronym{POSIX} is silent on whether this is
+acceptable.
 
 @node Location
 @section Printing current location
@@ -6072,12 +6073,19 @@
 @chapter Compatibility with other versions of @code{m4}
 
 @cindex compatibility
-This chapter describes the differences between this implementation of
address@hidden, and the implementation found under UNIX, notably System V,
-Release 3.
-
-There are also differences in BSD flavors of @code{m4}.  No attempt
-is made to summarize these here.
+This chapter describes the many of the differences between this
+implementation of @code{m4}, and of other implementations found under
+UNIX, such as System V Release 3, Solaris, and @acronym{BSD} flavors.
+In particular, it lists the known differences and extensions to
address@hidden  However, the list is not necessarily comprehensive.
+
+At the time of this writing, @acronym{POSIX} 2001 (also known as IEEE
+Std 1003.1-2001) is the latest standard, although a new version of
address@hidden is under development and includes several proposals for
+modifying what @code{m4} is required to do.  The requirements for
address@hidden are shared between @acronym{SUSv3} and @acronym{POSIX}, and
+can be viewed at
address@hidden://www.opengroup.org/onlinepubs/@/000095399/@/utilities/@/m4.html}.
 
 @menu
 * Extensions::                  Extensions in @acronym{GNU} M4
@@ -6086,7 +6094,7 @@
 @end menu
 
 @node Extensions
address@hidden Extensions in @acronym{GNU} @code{m4}
address@hidden Extensions in @acronym{GNU} M4
 
 @cindex @acronym{GNU} extensions
 @cindex @acronym{POSIX}
@@ -6152,7 +6160,8 @@
 @item
 Searches and text substitution through basic regular expressions are
 supported by the @code{regexp} (@pxref{Regexp}) and @code{patsubst}
-(@pxref{Patsubst}) builtins.
+(@pxref{Patsubst}) builtins.  Some @acronym{BSD} implementations use
+extended regular expressions instead.
 
 @item
 The output of shell commands can be read into @code{m4} with
@@ -6183,16 +6192,16 @@
 creating a new file with a unique name on every invocation, rather than
 following the insecure behavior of replacing the trailing @samp{X}
 characters with the @code{m4} process id.
address@hidden itemize
 
-In addition to the above extensions, @acronym{GNU} @code{m4} implements the
-following command line options: @option{-F}, @option{-G}, @option{-I},
address@hidden, @option{-R}, @option{-V}, @option{-W}, @option{-d}, @option{-i},
address@hidden, @option{--debugfile} and @option{-t}.  @xref{Invoking m4}, for a
address@hidden
address@hidden only requires support for the command line options
address@hidden, @option{-D}, and @option{-U}, so all other options accepted
+by @acronym{GNU} M4 are extensions.  @xref{Invoking m4}, for a
 description of these options.
 
-Also, the debugging and tracing facilities in @acronym{GNU} @code{m4} are much
+The debugging and tracing facilities in @acronym{GNU} @code{m4} are much
 more extensive than in most other versions of @code{m4}.
address@hidden itemize
 
 @node Incompatibilities
 @section Facilities in System V @code{m4} not in @acronym{GNU} @code{m4}
@@ -6390,9 +6399,9 @@
 the sync lines when the text is being diverted, and System V @code{m4}
 when the diverted text is being brought back.
 
-The problem is which lines and file names should be attached to text that
-is being, or has been, diverted.  System V @code{m4} regards all the
-diverted text as being generated by the source line containing the
+The problem is which lines and file names should be attached to text
+that is being, or has been, diverted.  System V @code{m4} regards all
+the diverted text as being generated by the source line containing the
 @code{undivert} call, whereas @acronym{GNU} @code{m4} regards the
 diverted text as being generated at the time it is diverted.