From a179d867391b05923ef3a6dbbe04eb63f5b264b1 Mon Sep 17 00:00:00 2001 From: Boris Kolpackov Date: Mon, 17 Oct 2016 17:24:47 +0200 Subject: Move cxx-style.txt to doc/ --- cxx-style.txt | 66 ----------------------------------------------------------- 1 file changed, 66 deletions(-) delete mode 100644 cxx-style.txt (limited to 'cxx-style.txt') diff --git a/cxx-style.txt b/cxx-style.txt deleted file mode 100644 index 8e968b8..0000000 --- a/cxx-style.txt +++ /dev/null @@ -1,66 +0,0 @@ -0. Don't try to be clever, prefer value/move semantics - -These days optimizers can often "see through" (via constexpr/inline/lto) and -optimize simple code that uses value semantics to the equivalent (or even -better) "clever" code that tries to avoid extra copies, allocations, etc. - -See also the note on small value optimization. - -1. Modernization - -- use override -- consider constexpr for inline functions (e.g., enum class bitmask operators) -- consider noexcept -? migrate to #pragma once - -2. Almost never auto - -Using auto instead of the actual type often makes code harder to understand. -You may (but don't have to) use auto when (a) the type is spelled out on the -right hand side (e.g., casts, make_*<>() functions, etc), and (b) in cases of -idiomatic use where the type is clear to anyone familiar with C++ and it would -be painful to spell it out explicitly. - -Examples of the latter are lambda initializations, iterator initializations -(e.g, from begin()), and some cases of pair initialization (e.g, from -container's insert()). - -3. Almost never brace-initialization - -We only use brace-initialization syntax when initializing an aggregate or a -container. We can also use it for an aggregate-like initialization of an -aggregate-like class. - -An aggregate-like class is class with public data members only and an -aggregate-like initialization is an initialization that provides initializers -for every such data member. For example: - -struct foo -{ - int x, y; - - foo (int x, int y); - foo (int both); -}; - -foo x {0, 1}; // Ok. -foo x {0}; // Bad. - -For default member variable initialization use assignment syntax, for example: - -struct foo -{ - int i = 123; - string s = string (123, 's'); -}; - -4. Many performance-critical standard types are "small object optimized" - -For example, across all the implementations that we care, std::string can hold -at least 15 characters without allocation. Similarly, std::function can hold a -lambda with at least 2 pointers also without allocation. - -As a result, it is seldom makes sense to resort to elaborate optimizations -such as string pooling. In fact, if we have a string pool that contains mostly -short, SOO strings, then we will most likely hurt performance due to lack of -locality. -- cgit v1.1