C中的枚举类型警告

Question

我在lpc1788 ARM Cortex M3上编写代码.当我尝试将端口配置为GPIO时,我遇到了一个奇怪的警告.尽管有警告,代码工作得非常好,但要了解为什么会出现这个警告,我在这里提出这篇文章.以下是我写的代码.

static uint32_t * PIN_GetPointer(uint8_t portnum, uint8_t pinnum)  
{  
    uint32_t *pPIN = NULL;  
    pPIN = (uint32_t *)(LPC_IOCON_BASE + ((portnum * 32 + pinnum)*sizeof(uint32_t)));  
    return pPIN;  
}    

void PINSEL_SetPinMode ( uint8_t portnum, uint8_t pinnum, PinSel_BasicMode modenum)  
{  
    uint32_t *pPIN = NULL;  
    pPIN = PIN_GetPointer(portnum, pinnum);  
    *(uint32_t *)pPIN &= ~(3<<3);    //Clear function bits  
    *(uint32_t *)pPIN |= (uint32_t)(modenum<<3);  
}  

int main(void)  
{  
    PINSEL_SetPinMode(1,15,0);  //this gave a warning: enumerated type mixed with another type  
    PINSEL_SetPinMode(1,18,PINSEL_BASICMODE_NPLU_NPDN);    //this doesnt give any warning  

   /* Following is the enum present in a GPIO related header file, putting it here in comments so that   
       those who are going through this post, can see the enum  

            typedef enum
            {
                PINSEL_BASICMODE_NPLU_NPDN  = 0, // Neither Pull up nor pull down        
                PINSEL_BASICMODE_PULLDOWN,       // Pull-down enabled
                PINSEL_BASICMODE_PULLUP,         // Pull-up enabled (default)         
                PINSEL_BASICMODE_REPEATER        // Repeater mode          
            }PinSel_BasicMode;        
   */

    return 0;  
}     

Answer 1

您正在使用需要int类型的enum PinSel_BasicMode类型.虽然枚举和整数通常是可以互换的,但它们是不同的类型.

值0不是枚举值.PINSEL_BASICMODE_NPLU_NPDN是.只有0通过定义.

如果枚举声明更改并且PINSEL_BASICMODE_NPLU_NPDN等于1,则代码将无效.