C++11: Remove const from in auto guidelines

Using const is orthogonal to guidelines on using auto& and auto*.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203257 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan P. N. Exon Smith 2014-03-07 18:06:15 +00:00
parent f7952d3a5f
commit feed88059f

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@ -746,23 +746,21 @@ The convenience of ``auto`` makes it easy to forget that its default behavior
is a copy. Particularly in range-based ``for`` loops, careless copies are
expensive.
As a rule of thumb, use ``const auto &`` unless you need to mutate or copy the
result, and use ``const auto *`` when copying pointers.
As a rule of thumb, use ``auto &`` unless you need to copy the result, and use
``auto *`` when copying pointers.
.. code-block:: c++
// Typically there's no reason to mutate or modify Val.
// Typically there's no reason to copy.
for (const auto &Val : Container) { observe(Val); }
// Remove the const if you need to modify Val.
for (auto &Val : Container) { Val.change(); }
// Remove the reference if you really want a new copy.
for (auto Val : Container) { Val.change(); saveSomewhere(Val); }
// Copy pointers, but make it clear that they're pointers.
for (const auto *Val : Container) { observe(*Val); }
for (auto *Val : Container) { Val->change(); }
for (const auto *Ptr : Container) { observe(*Ptr); }
for (auto *Ptr : Container) { Ptr->change(); }
Style Issues
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