Go – How to print the memory address of a slice in Golang

gomemory-addressslice

I have some experience in C and I am totally new to golang.

func learnArraySlice() {
  intarr := [5]int{12, 34, 55, 66, 43}
  slice := intarr[:]
  fmt.Printf("the len is %d and cap is %d \n", len(slice), cap(slice))
  fmt.Printf("address of slice 0x%x add of Arr 0x%x \n", &slice, &intarr)
}

Now in golang slice is a reference of array which contains the pointer to an array len of slice and cap of slice but this slice will also be allocated in memory and i want to print the address of that memory. But unable to do that.

Best Answer

http://golang.org/pkg/fmt/

fmt.Printf("address of slice %p add of Arr %p \n", &slice, &intarr)

%p will print the address.

Related Solutions

What exactly is a C pointer if not a memory address

The C standard does not define what a pointer is internally and how it works internally. This is intentional so as not to limit the number of platforms, where C can be implemented as a compiled or interpreted language.

A pointer value can be some kind of ID or handle or a combination of several IDs (say hello to x86 segments and offsets) and not necessarily a real memory address. This ID could be anything, even a fixed-size text string. Non-address representations may be especially useful for a C interpreter.

Go – How to get the underlying array of a slice in Go

First, if you haven't already, you should read this official blog post about slice internals. That should clear up everything.

Now to access the underlying array, you can use a combination of reflect and unsafe. In particular, reflect.SliceHeader contains a Data field which contains a pointer to the underlying array of a slice.

Example adapted from the documentation of the unsafe package:

s := []int{1, 2, 3, 4}
hdr := (*reflect.SliceHeader)(unsafe.Pointer(&s))
data := *(*[4]int)(unsafe.Pointer(hdr.Data))

Best Answer

Related Solutions

What exactly is a C pointer if not a memory address

Go – How to get the underlying array of a slice in Go

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