| Message ID | 20190212222021.28517-5-jacopo@jmondi.org |
|---|---|
| State | Accepted |
| Headers | show |
| Series |
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| Related | show |
Hi Jacopo, Thank you for the patch. On Tue, Feb 12, 2019 at 11:20:21PM +0100, Jacopo Mondi wrote: > Using std::move() on return statement of a method or on the its returned > value prevents the compiler from implementing copy-elision. Discourage > that in the coding style document. > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> I haven't explicitly given my SoB for this one, so please don't add it yourself. To record the advices I gave you, you could use Suggested-by. This being said, I hereby give you my Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> :-) > Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > --- > Documentation/coding-style.rst | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/Documentation/coding-style.rst b/Documentation/coding-style.rst > index 51afef27e9c1..065fbe0ab07b 100644 > --- a/Documentation/coding-style.rst > +++ b/Documentation/coding-style.rst > @@ -151,6 +151,10 @@ reference for the duration of the operation that borrows it. > never by reference. The caller can decide whether to transfer its ownership > of the std::shared_ptr<> with std::move() or retain it. The callee shall > use std::move() if it needs to store the shared pointer. > + * Do not over-use std::move(), as it may prevent copy-elision. In particular > + a function returning a std::shared_ptr<> value shall not use std::move() in > + its return statements, and its callers shall not wrap the function call > + with std::move(). > * Borrowed references to shared objects are passed as references to the > objects themselves, not to the std::shared_ptr<>, with the same rules as > for single owner objects.
Hi Jacopo, Thanks for your work. On 2019-02-12 23:20:21 +0100, Jacopo Mondi wrote: > Using std::move() on return statement of a method or on the its returned > value prevents the compiler from implementing copy-elision. Discourage > that in the coding style document. > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> > --- > Documentation/coding-style.rst | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/Documentation/coding-style.rst b/Documentation/coding-style.rst > index 51afef27e9c1..065fbe0ab07b 100644 > --- a/Documentation/coding-style.rst > +++ b/Documentation/coding-style.rst > @@ -151,6 +151,10 @@ reference for the duration of the operation that borrows it. > never by reference. The caller can decide whether to transfer its ownership > of the std::shared_ptr<> with std::move() or retain it. The callee shall > use std::move() if it needs to store the shared pointer. > + * Do not over-use std::move(), as it may prevent copy-elision. In particular > + a function returning a std::shared_ptr<> value shall not use std::move() in > + its return statements, and its callers shall not wrap the function call > + with std::move(). > * Borrowed references to shared objects are passed as references to the > objects themselves, not to the std::shared_ptr<>, with the same rules as > for single owner objects. > -- > 2.20.1 > > _______________________________________________ > libcamera-devel mailing list > libcamera-devel@lists.libcamera.org > https://lists.libcamera.org/listinfo/libcamera-devel
diff --git a/Documentation/coding-style.rst b/Documentation/coding-style.rst index 51afef27e9c1..065fbe0ab07b 100644 --- a/Documentation/coding-style.rst +++ b/Documentation/coding-style.rst @@ -151,6 +151,10 @@ reference for the duration of the operation that borrows it. never by reference. The caller can decide whether to transfer its ownership of the std::shared_ptr<> with std::move() or retain it. The callee shall use std::move() if it needs to store the shared pointer. + * Do not over-use std::move(), as it may prevent copy-elision. In particular + a function returning a std::shared_ptr<> value shall not use std::move() in + its return statements, and its callers shall not wrap the function call + with std::move(). * Borrowed references to shared objects are passed as references to the objects themselves, not to the std::shared_ptr<>, with the same rules as for single owner objects.