[PATCH v2] Documentation/process/coding-style.rst: space around const

From: Max Kellermann
Date: Tue Oct 10 2023 - 08:29:44 EST


There are currently no rules on the placement of "const", but a recent
code submission revealed that there is clearly a preference for spaces
around them.

checkpatch.pl has no check at all for this; though it does sometimes
complain, but only because it erroneously thinks that the "*" (on
local variables) is an unary dereference operator, not a pointer type.

Current coding style for const pointers-to-pointers:

"*const*": 2 occurrences
"* const*": 3
"*const *": 182
"* const *": 681

Just const pointers:

"*const": 2833 occurrences
"* const": 16615

Changed in v2: removed "volatile" on gregkh's request.

Link: https://lore.kernel.org/r/264fa39d-aed6-4a54-a085-107997078f8d@xxxxxxxxxxxx/
Link: https://lore.kernel.org/r/f511170fe61d7e7214a3a062661cf4103980dad6.camel@xxxxxxxxxxx/
Signed-off-by: Max Kellermann <max.kellermann@xxxxxxxxx>
---
Documentation/process/coding-style.rst | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst
index 6db37a46d305..71d62d81e506 100644
--- a/Documentation/process/coding-style.rst
+++ b/Documentation/process/coding-style.rst
@@ -271,6 +271,17 @@ adjacent to the type name. Examples:
unsigned long long memparse(char *ptr, char **retptr);
char *match_strdup(substring_t *s);

+Use space around the ``const`` keyword (except when adjacent to
+parentheses). Example:
+
+.. code-block:: c
+
+ const void *a;
+ void * const b;
+ void ** const c;
+ void * const * const d;
+ int strcmp(const char *a, const char *b);
+
Use one space around (on each side of) most binary and ternary operators,
such as any of these::

--
2.39.2