From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752570AbYKGVwx (ORCPT ); Fri, 7 Nov 2008 16:52:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751434AbYKGVwq (ORCPT ); Fri, 7 Nov 2008 16:52:46 -0500 Received: from rcsinet12.oracle.com ([148.87.113.124]:21971 "EHLO rgminet12.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751171AbYKGVwp (ORCPT ); Fri, 7 Nov 2008 16:52:45 -0500 Date: Fri, 7 Nov 2008 13:51:32 -0800 From: Randy Dunlap To: lkml Cc: akpm , Alexey Dobriyan Subject: [PATCH] DOC: add printk-formats.txt Message-Id: <20081107135132.a6fe9bba.randy.dunlap@oracle.com> Organization: Oracle Linux Eng. X-Mailer: Sylpheed 2.5.0 (GTK+ 2.12.0; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Source-IP: acsmt704.oracle.com [141.146.40.82] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A0B0202.4914B884.0102:SCFSTAT928724,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Randy Dunlap Add printk-formats.txt so that we don't have to keep fixing the same things over and over again. Signed-off-by: Randy Dunlap cc: Alexey Dobriyan --- Documentation/00-INDEX | 2 ++ Documentation/printk-formats.txt | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+) --- linux-next-20081107.orig/Documentation/00-INDEX +++ linux-next-20081107/Documentation/00-INDEX @@ -290,6 +290,8 @@ powerpc/ - directory with info on using Linux with the PowerPC. preempt-locking.txt - info on locking under a preemptive kernel. +printk-formats.txt + - how to get printk format specifiers right prio_tree.txt - info on radix-priority-search-tree use for indexing vmas. ramdisk.txt --- /dev/null +++ linux-next-20081107/Documentation/printk-formats.txt @@ -0,0 +1,36 @@ +If variable is of Type, use printk format specifier: +--------------------------------------------------------- + int %d or %x + unsigned int %u or %x + long %ld or %lx + unsigned long %lu or %lx + long long %lld or %llx + unsigned long long %llu or %llx + size_t %zu or %zx + ssize_t %zd or %zx + +Raw pointer value SHOULD be printed with %p. + +u64 SHOULD be printed with %llu/%llx, (unsigned long long): + + printk("%llu", (unsigned long long)u64_var); + +s64 SHOULD be printed with %lld/%llx, (long long): + + printk("%lld", (long long)s64_var); + +If is dependent on a config option for its size (e.g., sector_t, +blkcnt_t, phys_addr_t, resource_size_t) or is architecture-dependent +for its size (e.g., tcflag_t), use a format specifier of its largest +possible type and explicitly cast to it. Example: + + printk("test: sector number/total blocks: %llu/%llu\n", + (unsigned long long)sector, (unsigned long long)blockcount); + +Reminder: sizeof() result is of type size_t. + +Thank you for your cooperation and attention. + + +Written by Alexey Dobriyan +Updated by Randy Dunlap