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[Android] Gate getifaddrs behind API 24 availability #3506

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[Android] Gate getifaddrs behind API 24 availability #3506

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ded98ec
gate getifaddrs behind android availability
madsodgaard Feb 8, 2026
17cf7e8
Merge branch 'main' into getifaddrs-availability
Lukasa Feb 9, 2026
01b30a5
run swift format
madsodgaard Feb 9, 2026
8769337
Merge remote-tracking branch 'origin/getifaddrs-availability' into ge…
madsodgaard Feb 9, 2026
4905028
Merge branch 'main' into getifaddrs-availability
Lukasa Feb 10, 2026
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7 changes: 7 additions & 0 deletions Sources/NIOCore/SystemCallHelpers.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,9 @@ private let sysRead: @convention(c) (CInt, UnsafeMutableRawPointer?, size_t) ->

#if os(Android)
private let sysIfNameToIndex: @convention(c) (UnsafePointer<CChar>) -> CUnsignedInt = if_nametoindex
#if compiler(>=6.3)
@available(Android 24, *)
#endif
private let sysGetifaddrs: @convention(c) (UnsafeMutablePointer<UnsafeMutablePointer<ifaddrs>?>) -> CInt = getifaddrs
#elseif !os(WASI)
private let sysIfNameToIndex: @convention(c) (UnsafePointer<CChar>?) -> CUnsignedInt = if_nametoindex
Expand Down Expand Up @@ -228,8 +231,12 @@ enum SystemCalls {
}

#if !os(Windows)

@inline(never)
@usableFromInline
#if compiler(>=6.3)
@available(Android 24, *)
#endif
internal static func getifaddrs(_ addrs: UnsafeMutablePointer<UnsafeMutablePointer<ifaddrs>?>) throws {
_ = try syscall(blocking: false) {
sysGetifaddrs(addrs)
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6 changes: 6 additions & 0 deletions Sources/NIOCore/Utilities.swift
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Expand Up @@ -160,6 +160,9 @@ public enum System: Sendable {
/// - Returns: An array of network interfaces available on this machine.
/// - Throws: If an error is encountered while enumerating interfaces.
@available(*, deprecated, renamed: "enumerateDevices")
#if compiler(>=6.3)
@available(Android 24, *)
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@Lukasa Lukasa Feb 9, 2026

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I'm not sufficiently Android-aware to know this impact here. Did this compile for Android API 23 prior to Swift 6.3, and now does not?

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@madsodgaard madsodgaard Feb 9, 2026

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No, but we added @available support for Android in 6.3, that's why the compiler condition

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@Lukasa Lukasa Feb 9, 2026

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So what happened to this code in the 6.2 compiler?

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@madsodgaard madsodgaard Feb 9, 2026 •
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It does not compile for Android 23, because the getifaddrs symbol is missing from the NDK in API 23 and below.

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@Lukasa Lukasa Feb 9, 2026

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The thing I'm trying to figure out is whether this change produces a break for anyone, where code that previously compiled now will not.

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@madsodgaard madsodgaard Feb 9, 2026 •
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I don't think it would break anything. If you tried to compile swift-nio API 23 before, it would fail. The only place I could theoretically see it breaking was if someone was building swift-nio using a custom Android SDK and their own shim for getifaddrs and using one of the enumerate functions. Then they would get a error that it is only available on API 24.

But that's quite a stretch imo 😄

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@Lukasa Lukasa Feb 9, 2026

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Agreed. I believe we have (limited) Android CI. Is there a reason this isn't triggering compile failures there? https://github.com/apple/swift-nio/actions/runs/21817139179/job/62941167486

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@madsodgaard madsodgaard Feb 9, 2026

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Yeah, currently the Android SDK is only compiled for API 28+. That should soon be brought down to 24, and I am working on API 23 support as well. So that's why its not appearing in CI.

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@Lukasa Lukasa Feb 9, 2026

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Gotcha, thanks.

#endif
public static func enumerateInterfaces() throws -> [NIONetworkInterface] {
var interfaces: [NIONetworkInterface] = []
interfaces.reserveCapacity(12) // Arbitrary choice.
Expand Down Expand Up @@ -190,6 +193,9 @@ public enum System: Sendable {
///
/// - Returns: An array of network devices available on this machine.
/// - Throws: If an error is encountered while enumerating interfaces.
#if compiler(>=6.3)
@available(Android 24, *)
#endif
public static func enumerateDevices() throws -> [NIONetworkDevice] {
var devices: [NIONetworkDevice] = []
devices.reserveCapacity(12) // Arbitrary choice.
Expand Down
14 changes: 13 additions & 1 deletion Sources/NIOMulticastChat/main.swift
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Expand Up @@ -53,7 +53,19 @@ let targetDevice: NIONetworkDevice? = {
if let interfaceAddress = CommandLine.arguments.dropFirst().first,
let targetAddress = try? SocketAddress(ipAddress: interfaceAddress, port: 0)
{
for device in try! System.enumerateDevices() {
let devices: [NIONetworkDevice]

#if compiler(>=6.3)
if #available(Android 24, *) {
devices = try! System.enumerateDevices()
} else {
fatalError("This demo only works on Android API 24+")
}
#else
devices = try! System.enumerateDevices()
#endif

for device in devices {
if device.address == targetAddress {
return device
}
Expand Down
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