CODEWITHSUNDEEP
gopointers
eldlich
eldlich

Reputation: 39

how to convert *int64 to *int32?

I have a *int64 as one of the parameters in my function, and I need to convert it to *int32 to meet the definition of the function I want to call.

func t1(x *int64) error {
    var y *int32   
    t2(y)
}
func t2(y *int32) error {}

And, if I want to convert *int32 to *int8, then do I need another function? Is there a way to handle such problems?

Upvotes: 2

Views: 4214

Answers (2)

nguyenhoai890
nguyenhoai890

Reputation: 1219

Now, Golang has generic types which can help you to have a generic converting function:

type IntNumber interface {
 int | int8 | int16 | int32 | int64
}
func IntNumberPointersToPointers(T IntNumber, K IntNumber)(from *T) *K {
  if from == nil {
    return nil
  }
  result := K(*from)
  return &result
}

You can call the function by:

// The result will be int
input := int32(100)
result := util.IntNumberPointersToPointers[int32, int](&input)

Go playground: https://go.dev/play/p/sRP17iFX6J6

Assume that you are aware about converting big int to smaller may cause data loss. E.g int64 to int32

Upvotes: 0

Volker
Volker

Reputation: 42413

[H]ow to convert *int64 to *int32?

You cannot.

Use var i32 int32 = int32(*x); t2(&i32); *x=int64(i32).

Upvotes: 2

Related Questions