C Void Pointer Parameter

Sometimes it s necessary to use void pointers for example when passing between c code and c functions.

C void pointer parameter. The void type of pointer is a special type of pointer. Function pointer in c. It is basically used to store the address of a function. A pointer of a pointer is still a pointer so it s accepted as a void.

You re expected to know which type to cast it to the compiler has no reflection capability to know what the underlying type. 2 minutes to read 2. In computer programming when void is used as a function return type it indicates that the function does not return a value when void appears in a pointer declaration it specifies that the pointer is universal. As we know that pointers are used to point some variables.

To do so simply declare the function parameter as a pointer type. When used as a function return type the void keyword specifies that the function does not return a value. Void ptr nullptr. Ptr is a void pointer that is currently a null pointer although some compilers allow deleting a void pointer that points to dynamically allocated memory doing so should be avoided as it can result in undefined behavior.

Therefore void pointers are pointers that point to a value that has no type and thus also an undetermined length and undetermined dereferencing properties. 12 8k 6 6 gold badges 44 44 silver badges 99 99 bronze badges. In c void represents the absence of type. 2 void pointers in c are used to implement generic functions in c.

In c we must explicitly typecast return value of malloc to int. C allows you to pass a pointer to a function. We can call the function by using the function pointer or we can also pass the pointer to another function as a parameter. When used for a function s parameter list void specifies that the function takes no parameters.

A pointer to void simply points to a raw memory location. C s malloc returns such a pointer expecting you to cast it to a particular type immediately. When used in a function s parameter list void indicates that the function takes no parameters. For example compare function which is used in qsort.

Similarly the function pointer is a pointer used to point functions. This gives void pointers a great. When used in the declaration of a pointer void specifies that the pointer is universal if a pointer s type is void the. Following a simple example where we pass an unsigned long pointer to a function and change the value inside the function which reflects back in the calling function.

It really isn t useful until you cast it to another pointer type. 1 void pointers cannot be. C pointers parameter passing void pointers. A void pointer is used when you want to indicate a pointer to a hunk of memory without specifying the type.