path: root/Documentation/printk-formats.txt
diff options
authorGeert Uytterhoeven <>2015-04-15 16:17:14 -0700
committerLinus Torvalds <>2015-04-15 16:35:23 -0700
commit7330660ed2e8d8d4c65b90cea62d8f1ed49c0104 (patch)
treebb7a2a8a7d4670037da7e669f534a12a3a3cfaf2 /Documentation/printk-formats.txt
parentd1c1b12137fff14363d0cf45c8b7a9ec5cd4578b (diff)
lib/vsprintf: document %p parameters passed by reference
This patch series improves the documentation for printk() formats, and adds support for printing clocks. The latter has always been a hassle if you wanted to support both the common and legacy clock frameworks. - '%pC' and '%pCn' print the name (Common Clock Framework) or address (legacy clock framework) of a clock, - '%pCr' prints the current clock rate. This patch (of 3): Make sure all %p extensions that take parameters by references are documented to do so. Signed-off-by: Geert Uytterhoeven <> Cc: Jonathan Corbet <> Cc: Mike Turquette <> Cc: Stephen Boyd <> Cc: Tetsuo Handa <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'Documentation/printk-formats.txt')
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 5a615c14f75d..71438f3eb0c0 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -54,6 +54,7 @@ Struct Resources:
For printing struct resources. The 'R' and 'r' specifiers result in a
printed resource with ('R') or without ('r') a decoded flags member.
+ Passed by reference.
Physical addresses types phys_addr_t:
@@ -132,6 +133,8 @@ MAC/FDDI addresses:
specifier to use reversed byte order suitable for visual interpretation
of Bluetooth addresses which are in the little endian order.
+ Passed by reference.
IPv4 addresses:
@@ -146,6 +149,8 @@ IPv4 addresses:
host, network, big or little endian order addresses respectively. Where
no specifier is provided the default network/big endian order is used.
+ Passed by reference.
IPv6 addresses:
%pI6 0001:0002:0003:0004:0005:0006:0007:0008
@@ -160,6 +165,8 @@ IPv6 addresses:
print a compressed IPv6 address as described by
+ Passed by reference.
IPv4/IPv6 addresses (generic, with port, flowinfo, scope):
%pIS or 0001:0002:0003:0004:0005:0006:0007:0008
@@ -186,6 +193,8 @@ IPv4/IPv6 addresses (generic, with port, flowinfo, scope):
specifiers can be used as well and are ignored in case of an IPv6
+ Passed by reference.
Further examples:
%pISfc or [1:2:3:4:5:6:7:8]/123456789
@@ -207,6 +216,8 @@ UUID/GUID addresses:
Where no additional specifiers are used the default little endian
order with lower case hex characters will be printed.
+ Passed by reference.
dentry names:
@@ -216,6 +227,8 @@ dentry names:
equivalent of %s dentry-> we used to use, %pd<n> prints
n last components. %pD does the same thing for struct file.
+ Passed by reference.
struct va_format:
@@ -231,6 +244,8 @@ struct va_format:
Do not use this feature without some mechanism to verify the
correctness of the format string and va_list arguments.
+ Passed by reference.
u64 SHOULD be printed with %llu/%llx:
printk("%llu", u64_var);