GRPC C STYLE GUIDE
=====================

Background
----------

Here we document style rules for C usage in the gRPC Core library.

General
-------

- 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).

Header Files
------------

- Public header files (those in the include/grpc tree) should compile as pedantic C89
- Public header files should be includable from C++ programs. That is, they should 
  include the following:
  ```c
  #ifdef __cplusplus
  extern "C" {
  # endif

  /* ... body of file ... */

  #ifdef __cplusplus
  }
  # endif
  ```
- Header files should be self-contained and end in .h.
- All header files should have a #define guard to prevent multiple inclusion.
  To guarantee uniqueness they should be based on the file's path.

  For public headers: include/grpc/grpc.h --> GRPC_GRPC_H

  For private headers: 
  src/core/channel/channel_stack.h --> GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_STACK_H

C99 Features
------------

- Variable sized arrays are not allowed
- Do not use the 'inline' keyword
- Flexible array members are allowed (https://en.wikipedia.org/wiki/Flexible_array_member)

Comments
--------

Within public header files, only `/* */` comments are allowed.

Within implementation files and private headers, either single line `//` 
or multi line `/* */` comments are allowed. Only one comment style per file is
allowed however (i.e. if single line comments are used anywhere within a file,
ALL comments within that file must be single line comments).

Symbol Names
------------

- Non-static functions must be prefixed by grpc_
- static functions must not be prefixed by grpc_
- enumeration values and #define names are uppercased, all others are lowercased
- Multiple word identifiers use underscore as a delimiter (NEVER camel casing)
