linuxswiftlibdispatch

Swift in Linux: use of unresolved identifier 'dispatch_async'

I compiled libdispatch. This code is working:

import Dispatch
var lockQueue = dispatch_queue_create("com.test.async", nil);

But if I put this code to end file:

dispatch_async(lockQueue) {
    print("test1");
}

I got an error:

use of unresolved identifier 'dispatch_async'

Solution

  • As I commented above, this appears to be a current limitation with the Swift Package Manager. It doesn't currently support the addition of the appropriate compile-time options, such as the ones needed to support blocks as inputs to GCD functions (-Xcc -fblocks).

    In the meantime, you can avoid the Swift Package Manager and compile your files directly using swiftc, with the appropriate options. An example is provided by sheffler in their test repository:

    swiftc -v -o gcd4 Sources/main.swift -I .build/debug -j8 -Onone -g -Xcc -fblocks -Xcc -F-module-map=Packages/CDispatch-1.0.0/module.modulemap -I Packages/CDispatch-1.0.0 -I /usr/local/include

    The -I options will pull in your module maps for libdispatch, so adjust those to match where you've actually placed these system module directories.