rspec/rules/S5825/rule.adoc

C provides a way of defining or aliasing a type through ``++typedef++``. On top of it, {cpp} adds ``++using++`` that can do the same and more.


Using a macro to define a type is inferior to the previous ways for two reasons:

* macros cannot be enclosed into scopes. Or at least, doing so is cumbersome and error-prone as in that case, the macro needs to be defined and undefined manually.
* macros are handled by the preprocessor and are not understood from the compiler. They can easily pollute the code in places where types are not expected. ``++typedef++`` and ``++using++`` are known to the compiler to define types and can be more strictly checked.

As a result, macros should not be used as a replacement to ``++typedef++`` or ``++using++``.


== Noncompliant Code Example

----
#define UINT unsigned int  // Noncompliant
#define INT int  // Noncompliant
UINT uabs( INT i );
----


== Compliant Solution

----
typedef unsigned int UINT;
typedef int INT;
UINT uabs( INT i );
----
or

----
using UINT = unsigned int;
using INT = int;
UINT uabs( INT i );
----


== See

* https://wiki.sei.cmu.edu/confluence/display/c/PRE03-C.+Prefer+typedefs+to+defines+for+encoding+non-pointer+types[CERT, PRE03-C.] - Prefer typedefs to defines for encoding non-pointer types