From: Miles Chen Date: Tue, 1 Oct 2019 10:04:49 +0000 (+0800) Subject: docs: printk-formats: add ptrdiff_t type to printk-formats X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=88288ed050adb5a96f6063d2d0e3e35bac8e84c2;p=linux.git 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 --- 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 ----------------