38 lines
1.3 KiB
Plaintext
38 lines
1.3 KiB
Plaintext
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C provides a way of defining or aliasing a type through <code>typedef</code>. On top of it, C++ adds <code>using</code> that can do the same and more.
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Using a macro to define a type is inferior to the previous ways for two reasons:
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* 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.
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* 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. <code>typedef</code> and <code>using</code> are known to the compiler to define types and can be more strictly checked.
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As a result, macros should not be used as a replacement to <code>typedef</code> or <code>using</code>.
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== Noncompliant Code Example
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----
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#define UINT unsigned int // Noncompliant
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#define INT int // Noncompliant
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UINT uabs( INT i );
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----
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== Compliant Solution
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----
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typedef unsigned int UINT;
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typedef int INT;
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UINT uabs( INT i );
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----
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or
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----
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using UINT = unsigned int;
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using INT = int;
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UINT uabs( INT i );
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----
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== See
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* 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
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