# I ^C it after a little while:

Program received signal SIGINT, Interrupt. 0x1212c62b0 in StgRun () at StgCRun.c:6 6 * STG-to-C glue.

So it stalls or loops (it sits at 98% of cpu) on entry to stg_init().

More info will have to wait until I try a debug build.

Try with a debugging RTS, and use 'stepi' rather than 'step' when in Haskell code (everything from StgRun onwards), because the debugger won't have any line number info. Cheers, Simon