我正在尝试将 ObjC stackoverflow 答案转换为 Swift 但失败了。看起来我正在通过 UnsafeMutablePointer<mach_msg_type_number_t>
当我应该通过 inout mach_msg_type_number_t
我似乎无法解决我的问题。根据我对 Swift 指针文档(不多)的理解,这些应该可以互换......?
下面有更多信息。
这是 objective-c :
struct task_basic_info info;
mach_msg_type_number_t size = sizeof(info);
kern_return_t kerr = task_info(mach_task_self(), TASK_BASIC_INFO, (task_info_t)&info, &size);
这里是我在 Swift 中得到的(很多行以便于类型检查)
let name: task_name_t = mach_task_self_
let flavor: task_flavor_t = task_flavor_t(MACH_TASK_BASIC_INFO)
var info: mach_task_basic_info
var size: mach_msg_type_number_t = UnsignedFixed(sizeof(mach_task_basic_info_t))
let kerr = task_info(name, flavor, info as task_info_t, &size)
task_info
签名是:
func task_info(target_task: task_name_t, flavor: task_flavor_t, task_info_out: task_info_t, task_info_outCnt: UnsafeMutablePointer<mach_msg_type_number_t>) -> kern_return_t
最后一行的错误是:
Cannot convert the expression's type '(@!lvalue task_name_t, task_flavor_t, task_info_t, inout mach_msg_type_number_t)' to type 'kern_return_t'
最佳答案
我花了一些时间来更新 Airspeed Velocity 对最新 swift 语法(Swift 3,beta 6)的回答,但这是我得到的:
func report_memory() {
var info = mach_task_basic_info()
let MACH_TASK_BASIC_INFO_COUNT = MemoryLayout<mach_task_basic_info>.stride/MemoryLayout<natural_t>.stride
var count = mach_msg_type_number_t(MACH_TASK_BASIC_INFO_COUNT)
let kerr: kern_return_t = withUnsafeMutablePointer(to: &info) {
$0.withMemoryRebound(to: integer_t.self, capacity: MACH_TASK_BASIC_INFO_COUNT) {
task_info(mach_task_self_,
task_flavor_t(MACH_TASK_BASIC_INFO),
$0,
&count)
}
}
if kerr == KERN_SUCCESS {
print("Memory in use (in bytes): \(info.resident_size)")
}
else {
print("Error with task_info(): " +
(String(cString: mach_error_string(kerr), encoding: String.Encoding.ascii) ?? "unknown error"))
}
}
希望对您有所帮助。
关于MACH_TASK_BASIC_INFO 的 Swift 指针问题,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/27556807/