What is the usage of “void” in the C language?

In the C language, void is a special type used to represent an empty type. It is typically used in the following scenarios:

1. empty

void printHello() {
    printf("Hello");
    // 无返回值
}

1. empty

void printHello(void) {
    printf("Hello");
}

1. a pointer to an unknown data type

void* ptr;
int num = 10;
ptr = # // 将int类型的指针赋值给void类型的指针

In conclusion, void in C language is a special type used to represent empty type or no return value.