StarMirror/CppCoreGuidelines
1
0
Fork 0
mirror of https://github.com/isocpp/CppCoreGuidelines.git synced 2024-03-22 13:30:58 +08:00
Code Issues Projects Releases Wiki Activity

Fix #903.

Browse Source
This commit is contained in:
Gabriel Dos Reis 2017-05-08 10:50:03 -07:00
parent ad6f863152
commit 52aa9ba997
1 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
CppCoreGuidelines.md
View File

@ -17298,18 +17298,29 @@ Flag `using namespace` at global scope in a header file.
To avoid files being `#include`d several times. To avoid files being `#include`d several times.
In order to avoid include guard collisions, do not just name the guard after the filename.
Be sure to also include a key and good differentiator, such as the name of library or component
the header file is part of.
##### Example ##### Example
// file foobar.h: // file foobar.h:
#ifndef FOOBAR_H #ifndef LIBRARY_FOOBAR_H
#define FOOBAR_H #define LIBRARY_FOOBAR_H
// ... declarations ... // ... declarations ...
#endif // FOOBAR_H #endif // LIBRARY_FOOBAR_H
##### Enforcement ##### Enforcement
Flag `.h` files without `#include` guards. Flag `.h` files without `#include` guards.
##### Note
Some implementations offer vendor extensions like `#pragma once` as alternative to include guards.
It is not standard and it is not portable. It injects the hosting machine's filesystem semantics
into your program, in addition to locking you down to a vendor.
Our recommendation is to write in ISO C++: See [rule P.2]((#Rp-Cplusplus).
### <a name="Rs-cycles"></a>SF.9: Avoid cyclic dependencies among source files ### <a name="Rs-cycles"></a>SF.9: Avoid cyclic dependencies among source files
##### Reason ##### Reason