Bug 4368 – Fork() on OS X 2.047 results in a core.thread.ThreadException

import core.sys.posix.unistd, std.stdio; void main() { auto pid = fork(); if( pid > 0 ) { writeln( "Parent" ); } else if( pid == 0 ) { writeln( "Child" ); } else { writeln( "Failed to fork!" ); } } $ ./fork Parent Child core.thread.ThreadException: Unable to load thread state ---------------- 5 fork 0x00006e0d thread_suspendAll + 85 6 fork 0x0000b014 D2gc3gcx3Gcx11fullcollectMFPvZk + 32 7 fork 0x0000afe1 D2gc3gcx3Gcx16fullcollectshellMFZk + 41 8 fork 0x0000a0c6 D2gc3gcx2GC18fullCollectNoStackMFZv + 54 9 fork 0x00008060 gc_term + 44 10 fork 0x0000cf1a D2rt6dmain24mainUiPPaZi6runAllMFZv + 90 11 fork 0x0000cdea D2rt6dmain24mainUiPPaZi7tryExecMFMDFZvZv + 42 12 fork 0x0000cd78 main + 168 13 fork 0x00001acd start + 53halle109-82:dbug admin$

// Workaround (+ possible clue to what the cause is) import core.sys.posix.unistd, core.thread, //++++ std.stdio; void main() { auto pid = fork(); if( pid > 0 ) { writeln( "Parent" ); } else if( pid == 0 ) { thread_attachThis(); // ++++ writeln( "Child" ); } else { writeln( "Failed to fork!" ); } }:

This isn't an issue anymore.