Prefer type definitions (typedef
) to macro definitions (#define
) when encoding types. Type definitions obey scope rules; macro definitions do not. textual substitution is inferior to using the type system. While type definitions for non-pointer types have similar advantages [Summit 2005], can make it more difficult to write const
-correct code (see DCL05-C. Use typedefs of non-pointer types only).
This noncompliant code example will not compile, because macros use textual substitution and not the type system:
#define MATRIX double matrix[4][4] MATRIX matrix_a; |
After preprocessing, this code example is translated to the following invalid declaration:
#define MATRIX double matrix[4][4] double matrix[4][4] matrix_a; |
Using type definitions instead of macro definitions in this compliant solution results in a valid declaration:
typedef double matrix[4][4]; matrix matrix_a; |
I don't actually know what is wrong with this:
#define uchar unsigned char |
Use type definitions to encode all non-pointer types.
typedef unsigned char uchar; |
Recommendation | Severity | Likelihood | Remediation Cost | Priority | Level |
---|---|---|---|---|---|
PRE03-C | Low | Unlikely | Medium | P2 | L3 |
Tool | Version | Checker | Description |
---|---|---|---|
Axivion Bauhaus Suite | CertC-PRE03 | ||
CC2.PRE03 | Fully implemented | ||
Helix QAC | C3413 | ||
LDRA tool suite | 79 S | Enhanced Enforcement |
Search for vulnerabilities resulting from the violation of this rule on the CERT website.
SEI CERT C++ Coding Standard | VOID PRE03-CPP. Prefer typedefs to defines for encoding types |
ISO/IEC TR 24772:2013 | Pre-processor Directives [NMP] |
[Saks 1999] | |
[Summit 2005] | Question 1.13 Question 11.11 |