C语言assert用法　　看到一个宏, 它大概是这样的:　　　　#define assert_param(expr) ((expr) ? (void)0 : assert_failed((u8 *)__FILE__, __LINE__))　　代码的含意简单, 关键是那个 (void)0 的用法, 我还是第一次见到(别笑).　　我用 void 的时候, 有两种情况:　　　　1.放到函数前面, 强调函数没有返回值, 也就是说函数不能作右值　　　　　　如: voi

 1 /* Exported types ------------------------------------------------------------*/
 2 /* Exported constants --------------------------------------------------------*/
 3 /* Uncomment the line below to expanse the "assert_param" macro in the 
 4    Standard Peripheral Library drivers code */
 5 /* #define USE_FULL_ASSERT    1 */
 6 
 7 /* Exported macro ------------------------------------------------------------*/
 8 #ifdef  USE_FULL_ASSERT
 9 
10 /**
11   * @brief  The assert_param macro is used for function\'s parameters check.
12   * @param  expr: If expr is false, it calls assert_failed function which reports 
13   *         the name of the source file and the source line number of the call 
14   *         that failed. If expr is true, it returns no value.
15   * @retval None
16   */
17   #define assert_param(expr) ((expr) ? (void)0 : assert_failed((uint8_t *)__FILE__, __LINE__))
18 /* Exported functions ------------------------------------------------------- */
19   void assert_failed(uint8_t* file, uint32_t line);
20 #else
21   #define assert_param(expr) ((void)0)
22 #endif /* USE_FULL_ASSERT */