From 88288ed050adb5a96f6063d2d0e3e35bac8e84c2 Mon Sep 17 00:00:00 2001 From: Miles Chen Date: Tue, 1 Oct 2019 18:04:49 +0800 Subject: 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(+) (limited to 'Documentation/core-api/printk-formats.rst') diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index ecbebf4ca8e7..8a0f49cd158b 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 ---------------- -- cgit