From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 1 Aug 2002 12:11:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 1 Aug 2002 12:11:58 -0400 Received: from ns.suse.de ([213.95.15.193]:1031 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id convert rfc822-to-8bit; Thu, 1 Aug 2002 12:11:56 -0400 Content-Type: text/plain; charset="us-ascii" From: Andreas Gruenbacher Organization: SuSE Linux AG To: linux-kernel@vger.kernel.org, bug-glibc@gnu.org Subject: Kernel/Glibc: EOPNOTSUPP vs. ENOTSUP vs. ENOTSUPP Date: Thu, 1 Aug 2002 18:15:23 +0200 X-Mailer: KMail [version 1.4] Cc: Nathan Scott , Tim Shimmin , Thorsten Kukuk , Andreas Schwab , Andreas Jaeger MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Message-Id: <200208011815.23462.agruen@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello, we have a bit of a mess concerning error definitions: POSIX 1003.1-200 defines the errors EOPNOTSUPP and ENOTSUP as follows: [ENOTSUP] Not supported. The implementation does not support this feature of the Realtime Option Group. [EOPNOTSUPP] Operation not supported on socket. The type of socket (address family or protocol) does not support the requested operation. The standard further says the numbers assigned to ENOTSUP and EOPNOTSUPP shall be unique. Glibc seems to follow, but not quite: [ENOTSUP] "Not supported". A function returns this error when certain parameter values are valid, but the functionality they request is not available. This can mean that the function does not implement a particular command or option value or flag bit at all. For functions that operate on some object given in a parameter, such as a file descriptor or a port, it might instead mean that only that specific object (file descriptor, port, etc.) is unable to support the other parameters given; different file descriptors might support different ranges of parameter values. If the entire function is not available at all in the implementation, it returns ENOSYS instead. [EOPNOTSUPP] "Operation not supported". The operation you requested is not supported. Some socket functions don't make sense for all types of sockets, and others may not be implemented for all communications protocols. In the GNU system, this error can happen for many calls when the object does not support the particular operation; it is a generic indication that the server knows nothing to do for that call. In Glibc's sysdeps/unix/sysv/linux/bits/errno.h it says: /* Linux has no ENOTSUP error code. */ # define ENOTSUP EOPNOTSUPP In the kernel we define EOPNOTSUPP (architecture specific) and ENOTSUPP (in include/linux/errno.h). ENOTSUPP doesn't exist inside POSIX. Is ENOTSUPP supposed to be the same as ENOTSUP? Some applications are already checking for ENOTSUP; if they are compiled against Glibs they currently will really check against EOPNOTSUPP. Renaming or aliasig ENOTSUPP to ENOTSUP will cause trouble, but aliasing ENOTSUP to EOPNOTSUPP leads to a conflict with POSIX. What shall be done? Regards, Andreas. ------------------------------------------------------------------ Andreas Gruenbacher SuSE Linux AG mailto:agruen@suse.de Deutschherrnstr. 15-19 http://www.suse.de/ D-90429 Nuernberg, Germany