README.md

SCStreamError Sample

Make sure to read my article about why mentioning SCStreamError crashes on older macOS versions.

Minimal sample to demonstrates executables referencing SCStreamError fail to start when running on a macOS before 12.3, because it can't find ScreenCaptureKit.

My assumption is that this is because SCError.h doesn't have API_AVAILABLE(macos(12.3)) annotations (at the time of writing 2023-03-09).

Creating a build

swift build -c release --arch x86_64 --arch arm64

The resulting binary can be found at .build/apple/Products/Release/scstreamerror-sample and can run on both Intel and Apple Silicon Macs.

Demonstrating the issue

Running the build product will work as expected on macOS 12.3+, but will crash on macOS versions from before, that don't ship with ScreenCaptureKit. The error reports that ScreenCaptureKit.framework can't be loaded:

dyld: Library not loaded: /System/Library/Frameworks/ScreenCaptureKit.framework/Versions/A/ScreenCaptureKit
  Referenced from: /Users/alice/Downloads/Archive/./SCStreamError-sample-bad
  Reason: image not found
Abort trap: 6

Workaround

Don't directy reference the SCStreamError or SCStreamError.Code types from code. Instead, use their raw values.

For example, instead of:

// Don't write this:
do {
    try await stream.stop()
} catch let error as SCStreamError where error.code == .attemptToStopStreamState {
    // ...
}

Instead use raw values:

// Write this instead:
let streamErrorDomain = "com.apple.ScreenCaptureKit.SCStreamErrorDomain"
let attemptToStopCode = -3808
do {
    try await stream.stop()
} catch let error as NSError where error.domain == streamErrorDomain && error.code == attemptToStopCode {
    // ...
}

Authors

Nonstrict B.V., Mathijs Kadijk & Tom Lokhorst, released under MIT License.