Snippet

Reinterpreting Fixed-Array Memory to Slices using unsafe.Slice

The unsafe package allows zero-copy conversions between fixed-size array pointers and dynamic slices. unsafe.Slice constructs a slice backed by the provided pointer and length, allowing mutations in the slice to directly mutate the underlying array memory.

snippet.go

package main
 
import (
	"fmt"
	"unsafe"
)
 
func main() {
	var arr [4]uint32 = [4]uint32{0x01, 0x02, 0x03, 0x04}
	ptr := unsafe.SliceData(arr[:])
	sl := unsafe.Slice(ptr, len(arr))
	sl[0] = 0xFF
	fmt.Printf("Original Array: %v\nReinterpreted Slice: %v\n", arr, sl)
}

Breakdown

ptr := unsafe.SliceData(arr[:])

Obtains a raw pointer to the underlying backing array element.

sl := unsafe.Slice(ptr, len(arr))

Creates a slice header backed directly by the memory starting at ptr with the specified length.

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Reinterpreting Fixed-Array Memory to Slices using unsafe.Slice

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