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authorGravatar Vijay Pai <vpai@google.com>2016-11-02 22:02:47 -0700
committerGravatar GitHub <noreply@github.com>2016-11-02 22:02:47 -0700
commitb37ace5d279925ecd7f8dd6dca03e20cb066ae50 (patch)
tree09e1654e0819011d955682d09909c0d77665fa9a /doc/cpp-style-guide.md
parent9895a56cd2d90aa587f405d0eabe01794a5b633a (diff)
parenta189b7b9f144ae811a5e725b102acb06cab31b89 (diff)
Merge pull request #8602 from vjpai/turn_it_to_11
Stop supporting non-C++11 conformant compilers - DO NOT MERGE INTO V1.0.X
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diff --git a/doc/cpp-style-guide.md b/doc/cpp-style-guide.md
index 0138ceb737..a1f91353fe 100644
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@@ -1,91 +1,9 @@
GRPC C++ STYLE GUIDE
=====================
-Background
-----------
-
-Here we document style rules for C++ usage in the gRPC C++ bindings
-and tests.
-
-General
--------
-
-- The majority of gRPC's C++ requirements are drawn from the [Google C++ style
-guide] (https://google.github.io/styleguide/cppguide.html)
- - However, gRPC has some additional requirements to maintain
- [portability] (#portability)
-- As in C, layout rules are defined by clang-format, and all code
+The majority of gRPC's C++ requirements are drawn from the [Google C++ style
+guide] (https://google.github.io/styleguide/cppguide.html). Additionally,
+as in C, layout rules are defined by clang-format, and all code
should be passed through clang-format. A (docker-based) script to do
so is included in [tools/distrib/clang\_format\_code.sh]
(../tools/distrib/clang_format_code.sh).
-
-<a name="portability"></a>
-Portability Restrictions
--------------------
-
-gRPC supports a large number of compilers, ranging from those that are
-missing many key C++11 features to those that have quite detailed
-analysis. As a result, gRPC compiles with a high level of warnings and
-treat all warnings as errors. gRPC also forbids the use of some common
-C++11 constructs. Here are some guidelines, to be extended as needed:
-- Do not use range-based for. Expressions of the form
- ```c
- for (auto& i: vec) {
- // code
- }
- ```
-
- are not allowed and should be replaced with code such as
- ```c
- for (auto it = vec.begin; it != vec.end(); it++) {
- auto& i = *it;
- // code
- }
- ```
-
-- Do not use lambda of any kind (no capture, explicit capture, or
-default capture). Other C++ functional features such as
-`std::function` or `std::bind` are allowed
-- Do not use brace-list initializers.
-- Do not compare a pointer to `nullptr` . This is because gcc 4.4
- does not support `nullptr` directly and gRPC implements a subset of
- its features in [include/grpc++/impl/codegen/config.h]
- (../include/grpc++/impl/codegen/config.h). Instead, pointers should
- be checked for validity using their implicit conversion to `bool`.
- In other words, use `if (p)` rather than `if (p != nullptr)`
-- Do not initialize global/static pointer variables to `nullptr`. Just let
- the compiler implicitly initialize them to `nullptr` (which it will
- definitely do). The reason is that `nullptr` is an actual object in
- our implementation rather than just a constant pointer value, so
- static/global constructors will be called in a potentially
- undesirable sequence.
-- Do not use `final` or `override` as these are not supported by some
- compilers. Instead use `GRPC_FINAL` and `GRPC_OVERRIDE` . These
- compile down to the traditional C++ forms for compilers that support
- them but are just elided if the compiler does not support those features.
-- In the [include] (../../../tree/master/include/grpc++) and [src]
- (../../../tree/master/src/cpp) directory trees, you should also not
- use certain STL objects like `std::mutex`, `std::lock_guard`,
- `std::unique_lock`, `std::nullptr`, `std::thread` . Instead, use
- `grpc::mutex`, `grpc::lock_guard`, etc., which are gRPC
- implementations of the prominent features of these objects that are
- not always available. You can use the `std` versions of those in [test]
- (../../../tree/master/test/cpp)
-- Similarly, in the same directories, do not use `std::chrono` unless
- it is guarded by `#ifndef GRPC_CXX0X_NO_CHRONO` . For platforms that
- lack`std::chrono,` there is a C-language timer called gpr_timespec that can
- be used instead.
-- `std::unique_ptr` must be used with extreme care in any kind of
- collection. For example `vector<std::unique_ptr>` does not work in
- gcc 4.4 if the vector is constructed to its full size at
- initialization but does work if elements are added to the vector
- using functions like `push_back`. `map` and other pair-based
- collections do not work with `unique_ptr` under gcc 4.4. The issue
- is that many of these collection implementations assume a copy
- constructor
- to be available.
-- Don't use `std::this_thread` . Use `gpr_sleep_until` for sleeping a thread.
-- [Some adjacent character combinations cause problems]
- (https://en.wikipedia.org/wiki/Digraphs_and_trigraphs#C). If declaring a
- template against some class relative to the global namespace,
- `<::name` will be non-portable. Separate the `<` from the `:` and use `< ::name`.