Abstract
- A Datatype whose value is Memory Address, and itself is located at a memory address too
- In the diagram below shows some Go codes, we create a pointer
var p *int32 = new(int32)and perform Pointer Dereference with*p
Pass data by pointer
Pass data to functions by pointer is memory-efficient. The data we pass into a function is basically a Memory Address to access that block of data. If we pass data into functions without pointer. We need to create an entire duplicate of data and pass it to the functions.
In Java, data is passed to functions by pointer by default. However in Go, we need to explicity specify the pointer datatype for the function input, then we can pass data by point!
Pointee
- The actual data that a Pointer points-to inside the Heap Segment
Pointer Dereference
Null Pointer
- Pointer that doesn’t point to any memory location, basically contains a invalid Memory Address
- In C, it is represented by
0ornullptr - In Java, it is represented by
null, Custom Datatype can benull - In Go, it is represented with
nil
Void Pointer
- A Pointer without Datatype aka a pre-defined size
- Used when we aren’t sure what the exact size of a variable like the return type of malloc
- We should always try to cast it to a specific type whenever it is possible
Rust
Rust Box
- A smart Pointer that represents Rust Ownership of values allocated on the Heap Segment
Rust References
- Non-owning pointers that points to Rust Box, thus they do not own the data they point to.
- Powers Rust Borrowing