From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 24 Jul 2006 19:55:45 +0000 (+0000)
Subject: (Limitations of Usual Tools): Warn about sed stripping
X-Git-Tag: AUTOCONF-2.60a~25
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dac52fe6c9c06e3b492a89d8cd58b52b89c6853c;p=thirdparty%2Fautoconf.git

(Limitations of Usual Tools): Warn about sed stripping
leading white space from text.
---

diff --git a/ChangeLog b/ChangeLog
index 4e652b7b7..942220a54 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,8 @@
 	* doc/autoconf.texi (Volatile Objects): Be even a little
 	less skeptical about "volatile", after discussion with
 	Bruno Haible on bug-gnulib.
+	(Limitations of Usual Tools): Warn about sed stripping
+	leading white space from text.  From Bruno Haible.
 
 2006-07-20  Paul Eggert  <eggert@cs.ucla.edu>
 
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 5f7ea2045..8dda7d12b 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -9838,7 +9838,7 @@ m4_foreach([myvar], [[foo], [bar, baz]],
 
 @defmac m4_foreach_w (@var{var}, @var{list}, @var{expression})
 @msindex{foreach_w}
-Loop over the whitespace-separated list @var{list}, assigning each value
+Loop over the white-space-separated list @var{list}, assigning each value
 to @var{var}, and expand @var{expression}.
 
 The deprecated macro @code{AC_FOREACH} is an alias of
@@ -13671,6 +13671,23 @@ Also note that Posix requires that the @samp{b}, @samp{t}, @samp{r}, and
 On the other hand, no white space is allowed between @samp{:} and the
 subsequent label name.
 
+Some @command{sed} implementations (e.g., MacOS X 10.4, Solaris 10
+@command{/usr/ucb/sed}) strip leading white space from the text of
+@samp{a}, @samp{c}, and @samp{i} commands.  Prepend a backslash to
+work around this incompatibility with Posix:
+
+@example
+$ @kbd{echo flushleft | sed -e 'a\}
+@kbd{   indented'}
+flushleft
+indented
+$ @kbd{echo foo | sed -e 'a\}
+@kbd{\   indented'}
+flushleft
+   indented
+@end example
+
+
 @item @command{sed} (@samp{t})
 @c ---------------------------
 @prindex @command{sed} (@samp{t})