From: Eric Blake <eblake@redhat.com>
Date: Fri, 11 Nov 2011 20:51:33 +0000 (-0700)
Subject: doc: mention export portability hint
X-Git-Tag: v2.68b~46
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2f3cec7dfc609308f645b593dc5e396f9f790f4d;p=thirdparty%2Fautoconf.git

doc: mention export portability hint

* doc/autoconf.texi (Limitations of Builtins) <export>: Document
export limitation.
Suggested by Bruno Haible.

Signed-off-by: Eric Blake <eblake@redhat.com>
---

diff --git a/ChangeLog b/ChangeLog
index e51f7d74..72b1dbcc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2011-11-11  Eric Blake  <eblake@redhat.com>
+
+	doc: mention export portability hint
+	* doc/autoconf.texi (Limitations of Builtins) <export>: Document
+	export limitation.
+	Suggested by Bruno Haible.
+
 2011-10-21  Stefano Lattarini  <stefano.lattarini@gmail.com>
 
 	fortran: define $GFC to "yes" if $FC is a GNU compiler
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index b6dc67b8..417c432d 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -17642,6 +17642,20 @@ $ @kbd{ash -c 'export foo; env | grep foo'}
 foo=
 @end example
 
+Posix requires @command{export} to honor assignments made as arguments,
+but older shells did not support this.  Portable scripts should separate
+assignments and exports into different statements (it does not matter if
+the export comes before or after the assignment).
+
+@example
+$ @kbd{bash -c 'export foo=bar; echo $foo'}
+bar
+$ @kbd{/bin/sh -c 'export foo=bar; echo $foo'}
+/bin/sh: foo=bar: is not an identifier
+$ @kbd{/bin/sh -c 'export foo; foo=bar; echo $foo'}
+bar
+@end example
+
 @item @command{false}
 @c ------------------
 @prindex @command{false}