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gomemory-managementslice
Himanshu
Himanshu

Reputation: 12675

Go slice stored in dynamic memory or static memory

I was searching for memory allocations of slices whether static at compile time or dynamic on fly. Since slices are pointers to the array in back and I have studied that for dynamic memory allocation, pointers are crucial. So what is the allocation of slice and how about maps.

Upvotes: 2

Views: 2689

Answers (1)

peterSO
peterSO

Reputation: 166569

type slice struct {
    array unsafe.Pointer
    len   int
    cap   int
}

The slice descriptor is a struct. make([]type, len, cap) returns a slice descriptor with a pointer to an underlying array with the given type, len (length), and cap (capacity). The slice descriptor and/or its underlying array are allocated on the stack and/or the heap.

type string struct {
    array unsafe.Pointer
    len   int
}

The string descriptor is a struct with a pointer to an underlying byte array with length len. Since strings are immutable, the capacity is redundant; it is always equal to the length. The string descriptor, from a literal or conversion, and/or its underlying array are allocated on the stack and/or the heap.

Consider a string as a special form of a byte slice. For example, slice expressions apply to both.

The Go Programming Language Specification

Slice expressions

Slice expressions construct a substring or slice from a string, array, pointer to array, or slice. There are two variants: a simple form that specifies a low and high bound, and a full form that also specifies a bound on the capacity.

Upvotes: 2

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