CERT C:Rec.PRE03-C

Prefer typedefs to defines for encoding non-pointer type

自 R2024a 起

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描述

规则定义

Prefer typedefs to defines for encoding non-pointer type.¹

Polyspace 实现

规则检查项检查问题宏中编码了非指针类型。

示例

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宏中编码的非指针类型

问题

当非指针类型使用 #define 预处理器指令而不是 typedef 编码为宏时，会发生此问题。在以下情况下，规则检查器不会报告违规：

指针类型通过宏进行编码。
您在宏中与类型一起编码修饰符，例如 static 或 volatile。这些修饰符不属于类型定义的一部分，因此无法在 typedef 语句中使用。
在代码中未使用用于编码非指针类型的宏。

风险

宏定义不遵循作用域规则，宏中编码的类型通过文本替换应用于代码。最佳做法是使用 typedef 类型对非指针类型进行编码。

修复

使用 typedef 编码非指针类型，而不是使用宏。

示例 - 在宏中编码的类型

在此示例中，规则检查器报告了对编码非指针类型的宏的违规情况。

#define MATRIX(X) double X[4][4]  //Noncompliant
#define MY_INTEGRAL_TYPE1(sign, base) sign base  //Noncompliant
#define QUAL_TYPE_MAC1 const int  //Unused - no violation reported
#define QUAL_TYPE_MAC3 static volatile int //Not a violation
                  // - volatile and static cannot be used with typedefs

void noncompliant ()
{
    MATRIX(tab);
	MY_INTEGRAL_TYPE1(unsigned, int) uint;
	QUAL_TYPE_MAC3 var3;
}

未使用的宏以及编码了修饰符（如 volatile 或 static）的宏不违反此规则。

更正 - 使用 typedef 声明来编码非指针类型

在此合规示例中，非指针类型使用 typedef 语句进行编码。

typedef double matrix[4][4];
typedef unsigned int myint;

void compliant ()
{
    matrix matrix_a;
	myint uint;
}

检查信息

组：Rec.01.预处理器 (PRE)

版本历史记录

在 R2024a 中推出

另请参阅

检查 SEI CERT-C (-cert-c)

主题

检查并审查编码标准违规

¹ This software has been created by MathWorks incorporating portions of: the “SEI CERT-C Website,” © 2017 Carnegie Mellon University, the SEI CERT-C++ Web site © 2017 Carnegie Mellon University, ”SEI CERT C Coding Standard – Rules for Developing safe, Reliable and Secure systems – 2016 Edition,” © 2016 Carnegie Mellon University, and “SEI CERT C++ Coding Standard – Rules for Developing safe, Reliable and Secure systems in C++ – 2016 Edition” © 2016 Carnegie Mellon University, with special permission from its Software Engineering Institute.

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