Julia, handle keyboard interrupt

Question

Title says it all. How can I handle or catch a SIGINT in julia? From the docs I assumed I just wanted to catch InterruptException using a try/catch block like the following

try
    while true
        println("go go go")
    end
catch ex
    println("caught something")
    if isa(ex, InterruptException)
        println("it was an interrupt")
    end
end

But I never enter the catch block when I kill the program with ^C.

edit: The code above works as expected from the julia REPL, just not in a script.

Answer 1

I see the same behavior as alto, namely that SIGINT kills the entire process when my code is run as a script but that it is caught as an error when run in the REPL. My version is quite up to date and looks rather similar to that of tholy:

julia> versioninfo()
Julia Version 0.3.7
Commit cb9bcae* (2015-03-23 21:36 UTC)
Platform Info:
  System: Linux (x86_64-linux-gnu)
  CPU: Intel(R) Core(TM) i7-3610QM CPU @ 2.30GHz
  WORD_SIZE: 64
  BLAS: libopenblas (DYNAMIC_ARCH NO_AFFINITY Sandybridge)
  LAPACK: libopenblas
  LIBM: libopenlibm
  LLVM: libLLVM-3.3

Digging through the source, I found hints that Julia's interrupt behavior is determined by an jl_exit_on_sigint option, which can be set via a ccall. jl_exit_on_sigint is 0 for the REPL, but it looks as if init.c sets it to 1 when running a Julia program file from the command line.

Adding the appropriate ccall makes alto's code works regardless of the calling environment:

ccall(:jl_exit_on_sigint, Void, (Cint,), 0)

try
    while true
        println("go go go")
    end
catch ex
    println("caught something")
    if isa(ex, InterruptException)
        println("it was an interrupt")
    end
end

This does seem to be a bit of a hack. Is there a more elegant way of selecting the interrupt behavior of the environment? The default seems quite sensible, but perhaps there should be a command line option to override it.