From 58e39e7f7b478bee950d011ab0ad906f1e830e00 Mon Sep 17 00:00:00 2001 From: Miles Chen Date: Tue, 1 Oct 2019 18:04:49 +0800 Subject: [PATCH] docs: printk-formats: add ptrdiff_t type to printk-formats When print the difference between two pointers, we should use the ptrdiff_t modifier %t. Signed-off-by: Miles Chen Signed-off-by: Jonathan Corbet --- Documentation/core-api/printk-formats.rst | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index ecbebf4ca8e7e..8a0f49cd158b9 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -135,6 +135,20 @@ equivalent to %lx (or %lu). %px is preferred because it is more uniquely grep'able. If in the future we need to modify the way the kernel handles printing pointers we will be better equipped to find the call sites. +Pointer Differences +------------------- + +:: + + %td 2560 + %tx a00 + +For printing the pointer differences, use the %t modifier for ptrdiff_t. + +Example:: + + printk("test: difference between pointers: %td\n", ptr2 - ptr1); + Struct Resources ---------------- -- 2.39.5