lkml.org 
[lkml]   [2021]   [Sep]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v4] docs: Explain the desired position of function attributes
    Date
    While discussing how to format the addition of various function
    attributes, some "unwritten rules" of ordering surfaced[1]. Capture as
    close as possible to Linus's preferences for future reference.

    (Though I note the dissent voiced by Joe Perches, Alexey Dobriyan, and
    others that would prefer all attributes live on a separate leading line.)

    [1] https://lore.kernel.org/mm-commits/CAHk-=wiOCLRny5aifWNhr621kYrJwhfURsa0vFPeUEm8mF0ufg@mail.gmail.com/

    Signed-off-by: Kees Cook <keescook@chromium.org>
    ---
    v4:
    - fix another stray "void"! This is why code needs a compiler... (thx randy)
    ---
    Documentation/process/coding-style.rst | 30 ++++++++++++++++++++++++++
    1 file changed, 30 insertions(+)

    diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst
    index 42969ab37b34..45b48510f5ec 100644
    --- a/Documentation/process/coding-style.rst
    +++ b/Documentation/process/coding-style.rst
    @@ -487,6 +487,36 @@ because it is a simple way to add valuable information for the reader.
    Do not use the ``extern`` keyword with function prototypes as this makes
    lines longer and isn't strictly necessary.

    +When writing a function declarations, please keep the `order of elements regular
    +<https://lore.kernel.org/mm-commits/CAHk-=wiOCLRny5aifWNhr621kYrJwhfURsa0vFPeUEm8mF0ufg@mail.gmail.com/>`_.
    +For example::
    +
    + extern __init void * __must_check action(enum magic value, size_t size, u8 count,
    + char *fmt, ...) __printf(4, 5) __malloc;
    +
    +The preferred order of elements for a function prototype is:
    +
    +- storage class (here, ``extern``, and things like ``static __always_inline`` even though
    + ``__always_inline`` is technically an attribute, it is treated like ``inline``)
    +- storage class attributes (here, ``__init`` -- i.e. section declarations, but also things like ``__cold``)
    +- return type (here, ``void *``)
    +- return type attributes (here, ``__must_check``)
    +- function name (here, ``action``)
    +- function parameters (here, ``(enum magic value, size_t size, u8 count, char *fmt, ...)``, noting that parameter names should always be included)
    +- function parameter attributes (here, ``__printf(4, 5)``)
    +- function behavior attributes (here, ``__malloc``)
    +
    +Note that for a function definition (e.g. ``static inline``), the compiler does
    +not allow function parameter attributes after the function parameters. In these
    +cases, they should go after the storage class attributes (e.g. note the changed
    +position of ``__printf(4, 5)``)::
    +
    + static __always_inline __init __printf(4, 5) void * __must_check action(enum magic value,
    + size_t size, u8 count, char *fmt, ...)
    + __malloc
    + {
    + ...
    + }

    7) Centralized exiting of functions
    -----------------------------------
    --
    2.30.2
    \
     
     \ /
      Last update: 2021-10-01 01:58    [W:4.862 / U:0.040 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site