Re: AC_SYS_RESTARTABLE_SYSCALLS

[Paul Eggert]

Ian Lance Taylor <address@hidden> writes:

> What is the logic behind obsoleting AC_SYS_RESTARTABLE_SYSCALLS in
> current versions of autoconf?  I searched the mailing lists at
> gnu.org

Here's the announcement of that change:

http://mail.gnu.org/archive/html/bug-autoconf/2001-06/msg00042.html

Short summary: I surveyed uses of AC_SYS_RESTARTABLE_SYSCALLS in GNU
code, and found only one use (in Bash), and it was used incorrectly.
I therefore concluded AC_SYS_RESTARTABLE_SYSCALLS was not needed any
more, and (worse) that it was confusing Autoconf users.


> The manual, and the program, suggest using sigaction with SA_RESTART.
> This is obviously useless.  Firstly not every system supports
> SA_RESTART

Which systems don't?  That info would be good to add to the manual.


> AC_SYS_RESTARTABLE_SYSCALLS is for systems which do not provide
> sigaction.

That part of the manual gives advice to people writing new code, and I
think it's safe to assume SA_RESTART in newly written code.  Many GNU
programs do that now, to no ill effect that I know of.  If I'm wrong,
though, I'd like to fix the manual.

AC_SYS_RESTARTABLE_SYSCALLS is still in autoconf, so nothing has been
broken (yet :-).  If people still need it for something, we'll keep it.