From: Ralf Wildenhues Date: Sat, 22 Jan 2011 08:28:44 +0000 (+0100) Subject: docs: update entry about unset. X-Git-Tag: v2.68b~119 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f27287014003d7cbcac13f4da263066b86398908;p=thirdparty%2Fautoconf.git docs: update entry about unset. * doc/autoconf.texi (Limitations of Builtins): NetBSD sh unset also fails upon `unset' of a variable that is not set. Bash 2.01 could also dump core over `unset MAILPATH'. Suggestion by Eric Blake. Signed-off-by: Ralf Wildenhues --- diff --git a/ChangeLog b/ChangeLog index 13594f18..8b7052aa 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2011-01-22 Ralf Wildenhues + + docs: update entry about unset. + * doc/autoconf.texi (Limitations of Builtins): NetBSD sh unset + also fails upon `unset' of a variable that is not set. Bash 2.01 + could also dump core over `unset MAILPATH'. + Suggestion by Eric Blake. + 2011-01-21 Ralf Wildenhues Fix LEXLIB and YYTEXT_POINTER with IRIX 6.5 flex 2.5.4. diff --git a/doc/autoconf.texi b/doc/autoconf.texi index 4cb3a8c6..7eccba7e 100644 --- a/doc/autoconf.texi +++ b/doc/autoconf.texi @@ -17758,13 +17758,15 @@ and file name expansion. @item @command{unset} @c ------------------ @prindex @command{unset} -In some nonconforming shells (e.g., Bash 2.05a), @code{unset FOO} fails -when @code{FOO} is not set. You can use +In some nonconforming shells (e.g., NetBSD 5.99.43 sh or Bash 2.05a), +@code{unset FOO} fails when @code{FOO} is not set. This can interfere +with @code{set -e} operation. You can use @smallexample FOO=; unset FOO @end smallexample +@noindent if you are not sure that @code{FOO} is set. A few ancient shells lack @command{unset} entirely. For some variables @@ -17777,8 +17779,8 @@ PS1='$ ' Usually, shells that do not support @command{unset} need less effort to make the environment sane, so for example is not a problem if you cannot unset @command{CDPATH} on those shells. However, Bash 2.01 mishandles -@code{unset MAIL} in some cases and dumps core. So, you should do -something like +@code{unset MAIL} and @code{unset MAILPATH} in some cases and dumps core. +So, you should do something like @smallexample ( (unset MAIL) || exit 1) >/dev/null 2>&1 && unset MAIL || :