Given an arbitrary memory address how do I find (in runtime) the nature of memory block it belongs to? For stack addresses I guess there's some "stack start" and "stack end" of the current thread. For other threads' stacks - I guess I'd have to enumerate all threads to get those ranges. I also found that I can use malloc_size and sometimes it gives me correct result (the size if non zero at least), although it doesn't give me the beginning of the block memory address belongs to. For anything else I have no clue at the moment. Ideal method I am looking for: struct MemoryBlock { let type: MemoryBlockType // stack, heap, unmapped, etc let start: UnsafeRawPointer let size: Int let attributes // e.g. red / write } func findMemoryBlock(_ address: UnsafeRawPointer) -> MemoryBlock PS. the language doesn't matter (e.g. can be C) so long as this method works in a swift/obj-c app.

Where's CBAdvDataManufacturerData format documented? It looks like there's the company code stored in little endian order in the first two bytes (referencing the companies found in company_identifiers.yaml on bluetooth site). And the rest is arbitrary? I'd like to see the official documentation about this. Thank you.

Why is "fork" prohibited in sandboxed apps?

Hi, Given pthread_id (†), is there a way to find the associated NSThread (when the one exists)? Perhaps using an undocumented / unsupported method – I don't mind. Thank you! (†) the pthread_id is neither of the current nor of the main thread.

Am I calling this right? host_priv_t hostPriv = 0; int err = host_get_host_priv_port(mach_host_self(), &hostPriv); err = host_processors(hostPriv, &processorList, &processorCount); host_get_host_priv_port above returns 4 "(os/kern) invalid argument". Tried with App Sandbox enabled and disabled.

I'm trying to reproduce a case when there are more dispatch queues than there are threads serving them. Is that a possible scenario?

The man page for getifaddrs states: The ifa_data field references address family specific data. For AF_LINK addresses it contains a pointer to the struct if_data (as defined in include file <net/if.h>) which contains various interface attributes and statistics. For all other address families, it contains a pointer to the struct ifa_data (as defined in include file <net/if.h>) which contains per-address interface statistics. I assume that "AF_LINK address" is the one that has AF_LINK in the p.ifa_addr.sa_family field. However I do not see "struct ifa_data" anywehere. Is this a documentation bug and if so how do I read this documentation right?

What best to pass to the options parameter of: MTLDevice.makeBuffer(length:options:) MTLDevice.makeBuffer(bytes:length:options:) MTLDevice.makeBuffer(bytesNoCopy:length:options:deallocator:) Basically I'm looking for a "plain English" explanation of MTLResourceOptions doc page.

While playing with this app I found something odd: let dylib1 = dlopen("/System/Library/Frameworks/CreateMLComponents.framework/CreateMLComponents", O_RDONLY)! let s1 = dlsym(dylib1, "CreateMLComponentsVersionString")! var info1 = Dl_info() let success1 = dladdr(s1, &info1) precondition(success1 != 0) print(String(cString: info1.dli_sname!)) // CreateMLComponentsVersionString let path1 = String(cString: info1.dli_fname!) print(path1) // /System/Library/Frameworks/CreateMLComponents.framework/Versions/A/CreateMLComponents let exists1 = FileManager.default.fileExists(atPath: path1) print(exists1) // true let dylib2 = dlopen("/System/Library/Frameworks/Foundation.framework/Foundation", O_RDONLY)! let s2 = dlsym(dylib2, "NSAllocateMemoryPages")! // var info2 = Dl_info() let success2 = dladdr(s2, &info2) precondition(success2 != 0) print(String(cString: info2.dli_sname!)) // NSAllocateMemoryPages let path2 = String(cString: info2.dli_fname!) print(path2) // /System/Library/Frameworks/Foundation.framework/Versions/C/Foundation let exists2 = FileManager.default.fileExists(atPath: path2) print(exists2) // false The app runs fine and prints true for exists1 and false for exists2. That means that while both dlsym calls succeed and both dladdr calls return paths (within CreateMLComponents.framework and Foundation.framework correspondingly) the first file exists while the second file doesn't exist. This raises quite a few questions: Why some of the dylib files (in fact – most dylibs inside /System/Library/Frameworks hirerarchy) don't exist at the expected locations? Why do we have symbolic link files (like Foundation.framework/Foundation) that point to those non-existent locations? What is the purpose of those symbols links? Where are those missing dylib files in fact? They must be somewhere, no?! I guess to figure out the answer I could search the whole disk raw bytes for a particular byte pattern to know the answer but hope there's an easier way to know the truth! Why do we have some exceptional cases like "CreateMLComponents.framework" and a couple of others that don't follow the rules established by the rest? Thanks!

I'm getting "unsatisfied (Local network prohibited)" when trying accessing my local http server running on mac (http://192.168.0.12:8000/test.txt) from an app running on iPhone with iOS 18.4. That's using URLSession, nothing fancy. This is the contents of the plist file of the app: NSAppTransportSecurity NSExceptionAllowsInsecureHTTPLoads true NSAllowsArbitraryLoads true NSAllowsLocalNetworking true NSExceptionDomains 192.168.0.12 NSIncludesSubdomains true NSAllowsLocalNetworking true NSExceptionAllowsInsecureHTTPLoads true NSLocalNetworkUsageDescription Hello The app correctly "prompts" the alert on the first app run, asking if I want to access local network, to which I say yes. Afterwards I could see that Local Network is enabled in iOS settings for the app, yet getting those "Local network prohibited" errors. From testing other global IP + 'http only" sites it feels like NSAllowsArbitraryLoads no longer works as it used to work before. But specifying other test "global" HTTP-only IP addresses in NSExceptionDomains work alright, it's just the local address doesn't. I could access that IP from iOS safari with no problem. The local web site is HTTP only. Googling reveals tons of relevant hits including FAQ articles from Quinn, but whatever I tried so far based on those hits doesn't seem to work.

I'm creating a simple p2p server to advertise a service: // server let txtRecord = NWTXTRecord(["key": "value"]) NWListener.Service(name: name, type: "_p2p._tcp", domain: nil, txtRecord: txtRecord) and client to look that service up: // client switch result.endpoint { case let .service(name: name, type: type, domain: domain, interface: interface): print(result.metadata) The client is getting the advertisement ok, but metadata is nil. I expected to see a txt record there, is that not supported? public let metadata: NWBrowser.Result.Metadata /// Additional metadata provided to the browser by a service. Currently, /// only Bonjour TXT records are supported. Is the above server making a Bonjour TXT record or something else? Basically what I want is to pass a short key/value data as part of advertisement.

I have an iOS app that allows user to select a folder (from local Files). User is seemingly capable selecting the "On My iPhone" folder (the "Open" button is enabled, clickable and when it is tapped the app gets the relevant URL) although there's nothing in that folder apart from ".trash" item. Is selecting that folder not supported? If not why is the "Open" button enabled on that level to begin with?

is JSONSerialization.jsonObject(with: inputStream) reliable? sometimes it works fine (e.g. with small objects) and sometimes it blocks forever (easier to get the block with big objects). yet sometimes it works ok even with big objects. tried to call it on a different queue - didn't help.

https://developer.apple.com/documentation/foundation/urlcache has this: "Although URLCache instance methods can safely be called from multiple execution contexts at the same time, be aware that methods like  cachedResponse(for:) and storeCachedResponse(_:for:) have an unavoidable race condition when attempting to read or write responses for the same request." What does it mean "unavoidable"? If I put a lock (mutex / NSLock, or similar) in my wrappers on top of "cachedResponse" / "storeCachedResponse" would that avoid the mentioned race condition? Also, what do they mean by "the same request"? A few examples below: let url = URL(string: "https://www.apple.com")! let req1 = URLRequest(url: url) let req2 = req1 // perhaps "the same" let req3 = URLRequest(url: url) // "the same"? let req4 = URLRequest(url: req1.url!) // "the same"? let req5 = URLRequest(url: url, cachePolicy: req1.cachePolicy, timeoutInterval: req1.timeoutInterval) // "the same"? let req6 = URLRequest(url: url, cachePolicy: req1.cachePolicy, timeoutInterval: 1234) // "the same"? let req7 = URLRequest(url: url, cachePolicy: .reloadIgnoringCacheData, timeoutInterval: req1.timeoutInterval) // "the same"? assert(req1 == req2) assert(req1 == req3) assert(req1 == req4) assert(req1 == req5) assert(req1 == req6) // this is ok assert(req1 == req7) // this fails

In the following simplified app I want to change the status bar color from default black to white (the main iPhone theme is light) but nothing else. I'm partly succeeded doing so, but the theme of keyboard is wrong: when it is first appeared it is good (light) and as soon as i start typing it changes itself to unwanted dark. Is there a way to change just the status bar color but nothing else? Note that I want the status bar color be dynamic - sometimes white, sometimes black depending upon what the app is doing. import SwiftUI struct ContentView: View {     @State var string = "Hello, World"     var body: some View {         TextField("EditableText", text: $string)             .font(.largeTitle)             .frame(maxHeight: 1000)             .navigationTitle("Hello, World")             .background(                 Color(red: 1, green: 0.7, blue: 0.7, opacity: 1)             )             .colorScheme(.light) // attempt to "undo" the effect             .preferredColorScheme(.dark)     } } @main struct NavBarTestApp: App {     var body: some Scene {         WindowGroup {             ContentView()         }     } } PS. I don't mind dropping to UIKit for status bar handling if it is not possible to do it in SwiftUI. The rest of app itself is SwiftUI and it is quite big, here I am showing a stripped down version.