Void of C language learning notes

Void of C language learning notes

? 1. void literally means "no type", void * means "no type Pointer", and void * can point to any type of data.

? 2. Usage 1: Data Type Encapsulation

Int InitHardEnv (void ** handle );

Typical function prototypes for memory operation functions such as memcpy and memset are

Void * memcpy (void * dest, const void * src, size_t len );

Void * memset (void * buffer, int c, size_t num );

? 3. Usage 2: Modify the return value and parameters of the void function, which only indicates none.

If the function does not return a value, declare it as void.

If the function has no parameters, you should declare the parameter as void.

Int function (void)

{Return 1 ;}

? 4. Significance of the void pointer

C language requires that only pointers of the same type can be assigned values to each other

Void * the pointer is used as the left value to receive any type of pointer.

Void * forced type conversion is required when the pointer is assigned to another pointer as the right value

Int * p1 = NULL;

Char * p2 = (char *) malloc (sizoeof (char) * 20 );

? 5. The void type variable does not exist.

The C language does not define the alias for how much memory the void is.