如何使C代码符合MISRA C:2012标准? [英] How to make C code to MISRA C:2012 compliance?

问题描述

我正在使用PC-Lint将MISRA C:2012标准验证为我的MCU代码. 我遇到了以下错误.在这里发布了示例代码，其中条件语句出现了错误.

I am validating MISRA C:2012 standard to my MCU code using PC-Lint. I got following errors.Here I posted a sample code where I got errors on condition statements.

1]无符号整数文字，不带'U'后缀[MISRA 2012 Rule 7.2，必填] S_LCB_100，

1] unsigned integer literal without a 'U' suffix [MISRA 2012 Rule 7.2, required] S_LCB_100,

2]逻辑运算符'&&'右侧的副作用[MISRA 2012规则13.5，必填] while(((0x00000000！= List [Loop])&&(0！= Counter))

2] side effects on right hand of logical operator, '&&' [MISRA 2012 Rule 13.5, required] while(( 0x00000000 != List[Loop] ) && ( 0 != Counter ))

3]:带符号的值和无符号的值不能同时用作！=的操作数[MISRA 2012 Rule 10.4，必需] while(((0x00000000！= List [Loop])&&(0！= Counter))

3] : a signed value and an unsigned value cannot be used together as operands to != [MISRA 2012 Rule 10.4, required] while(( 0x00000000 != List[Loop] ) && ( 0 != Counter ))

4]:带符号的值和无符号的值不能同时用作！= [MISRA 2012 Rule 10.4，required]的操作数while(((0x00000000！= List [Loop])&&(0！=计数器))

4] : a signed value and an unsigned value cannot be used together as operands to != [MISRA 2012 Rule 10.4, required] while(( 0x00000000 != List[Loop] ) && ( 0 != Counter ))

5]如果(List [Loop] == 0x00000000)

5] an unsigned value and a signed value cannot be used together as operands to == [MISRA 2012 Rule 10.4, required] if ( List[Loop] == 0x00000000 )

如何使它符合MISRA C:2012?

typedef unsigned char UINT8;
typedef unsigned char BYTE;  
typedef unsigned long int UINT32; 
#define S_LCB_100 0xF0BB12DE;
#define MULTI 0x1A;
volatile static BYTE Counter = 0;
static UINT8 Loop = 0;    
static UINT32 List[]=  
{
    S_LCB_100,
    0x00000000,
};
while(( 0x00000000 != List[Loop] ) && ( 0 != Counter ))
{
 .......some code
}
if ( List[Loop] == 0x00000000 )
{
.....some code
} 

推荐答案

一般说明:

• 在担心是否符合MISRA-C要求之前，请先获取要在C编译器上编译的代码.
• 然后确保您拥有MISRA-C:2012文档，或者您根本无法使用MISRA.
• 摆脱"Yoda条件"之类的废话.
• 摆脱自定义typedef并使用stdint.h.如果您使用的是C90，请使用stdint.h使用的名称来命名typedef.

• Before worrying about MISRA-C compliance, get the code to compile on a C compiler.
• Then make sure you have the MISRA-C:2012 document available or you simply cannot work with MISRA.
• Get rid of nonsense like "Yoda conditions".
• Get rid of custom typedefs and use stdint.h. If you are on C90 then typedef with the names used by stdint.h.

1]无符号整数文字，不带'U'后缀[MISRA 2012 Rule 7.2，必填] S_LCB_100，

1] unsigned integer literal without a 'U' suffix [MISRA 2012 Rule 7.2, required] S_LCB_100,

很容易解释.将U或u添加到应无符号的整数常量.有关详细信息，请阅读规则7.2.

Pretty self-explaining. Add U or u to integer constants that should be unsigned. Read rule 7.2 for details.

2]逻辑运算符'&&'右侧的副作用[MISRA 2012规则13.5，必填] while(((0x00000000！= List [Loop])&&(0！= Counter))

2] side effects on right hand of logical operator, '&&' [MISRA 2012 Rule 13.5, required] while(( 0x00000000 != List[Loop] ) && ( 0 != Counter ))

Counter具有挥发性限制，访问它是一种副作用.因此，一般来说，它不应该存在于复杂的表达式中，尤其是不应该位于布尔&&的右侧.表达式-这是非常可疑的代码.在这种情况下，您可以简单地将代码重写为:

Counter is voltatile-qualified and accessing it is a side-effect. So it should not exist inside complex expressions in general, and particularly not on the right hand side of a boolean && expression - that's quite questionable code. In this case you could simply rewrite the code as this:

uint32_t count = (uint32_t)Counter;

while((count != 0u) && (List[Loop] != 0u))
{
  ...
  count = (uint32_t)Counter; // read volatile variable in an expression of its own
}

3]带符号的值和无符号的值不能同时用作！= [MISRA 2012 Rule 10.4，required]的操作数while(((0x00000000！= List [Loop])&&(0！= Counter) )

3] a signed value and an unsigned value cannot be used together as operands to != [MISRA 2012 Rule 10.4, required] while(( 0x00000000 != List[Loop] ) && ( 0 != Counter ))

这是因为Counter被声明为BYTE.删除所有此类自制的废话类型，并将其声明为uint8_t.然后使用while形式，如上所示.使用u后缀.这应该将2)修复为5).

This is because Counter is declared as BYTE. Drop all such home-brewed crap types and declare it as uint8_t instead. Then use the while form as shown above. Use u suffix. This should fix 2) to 5).

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