Swift 中的 Realloc UnsafeMutablePointer 导致错误

Posted 2023-03-14

【中文标题】Swift 中的 Realloc UnsafeMutablePointer 导致错误

【英文标题】：Realloc UnsafeMutablePointer in Swift cause error

【发布时间】：2016-04-13 02:15:33

【问题描述】：

我正在将一些关于 C 指针的操作转换为 Swift。

var bits = UnsafeMutableBufferPointer<Int32>(start: nil, count: 0)

var startIdx: UnsafeMutablePointer<Int32> = nil 
    didSet 
        bits = UnsafeMutableBufferPointer<Int32>(start: startIdx, count: bitsLength)
        defer  bits.baseAddress.dealloc(bits.count) 
    


var size: Int = 0
var bitsLength: Int = 1

init(size: Int) 
    self.size = size
    self.bitsLength = (size + 31) / 32
    self.startIdx = UnsafeMutablePointer<Int32>.alloc(bitsLength * sizeof(Int32))


func ensureCapacity(size: Int) 
    if size > bitsLength * 32 
        let newBitsLength = (size + 31) / 32

        startIdx = realloc(startIdx, sizeof(Int32) * newBitsLength) 
        // Cannot convert value of type `UnsafeMutablePointer<Int32>` to type 'UnsafeMutablePointer<Void>'(aka `UnsafeMutablePointer<()>`) in coercion
    

我知道了

无法将UnsafeMutablePointer<Int32> 类型的值强制转换为类型“UnsafeMutablePointer”（又名UnsafeMutablePointer<()>）

有什么想法吗？

【参考方案1】：

这能帮上忙吗：

startIdx = unsafeBitCast(realloc(startIdx, sizeof(Int32) * newBitsLength), UnsafeMutablePointer<Int32>.self)