REPL crashing on ctrl+c?

[leotac]

I'm sure it's a known issue, but ctrl+c causes the REPL to crash (brutal segfault).
[If it only happens to me, I'd like to find out why :)]

Related: with Gurobi, ctrl+c takes me back to the REPL but the solver keeps running in the background, until it completes (or you quit the REPL) -- only marginally less annoying than a crash. Should probably open an issue there as well, if there isn't one already.

[joehuchette]

Yeah I see this as well, I mostly use CPLEX but I think I've noticed it for other solvers as well. I have pretty much no idea how to work around this though, but @mlubin maybe has some thoughts?

[mlubin]

I've seen similar issues but haven't been following the state of signal
handling in julia.
CC @tkelman @vtjnash
On Jul 30, 2015 1:02 PM, "Joey Huchette" [email protected] wrote:

Yeah I see this as well, I mostly use CPLEX but I think I've noticed it for
other solvers as well. I have pretty much no idea how to work around this
though, but @mlubin https://github.com/mlubin maybe has some thoughts?

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#45 (comment).

[tkelman]

might need some sigint fiddling? ref JuliaLang/julia#2622 and JuliaLang/julia#12309

[joehuchette]

So just wrapping e.g.

stat = disable_sigint() do
    @cpx_ccall(mipopt, Cint, (Ptr{Void}, Ptr{Void}), model.env.ptr, model.lp)
end

means CPLEX just keeps running after CTRL+C, which IMO is less desirable than a brutal segfault. Ideally we'd want to propagate the SIGINT to CPLEX so it can fail gracefully, but I'm not certain how to do that.

[leotac]

The CPLEX callable library does provide a function to terminate it gracefully: http://www-01.ibm.com/support/knowledgecenter/SSSA5P_12.6.2/ilog.odms.cplex.help/refcallablelibrary/cpxapi/setterminate.html?cp=SSSA5P_12.6.2%2F2-8-0-30-2&lang=en
I wonder if it's possible to (temporarily) replace the default Julia signal handler with something that ccalls CPXsetterminate(). Make sense?

[joehuchette]

Looks like maybe we could do something like this:

try 
    @cpx_ccall(mipopt, Cint, (Ptr{Void}, Ptr{Void}), model.env.ptr, model.lp)
catch ex
    if isa(ex, InterruptException)
        @cpx_ccall(setterminate, Cint, (Ptr{Void}, Ptr{Void}), model.env.ptr, CPLEX_SIGINT)
    else
        rethrow(ex)
    end
end

(ref http://stackoverflow.com/questions/20831290/julia-handle-keyboard-interrupt)

[joehuchette]

I don't know what CPLEX_SIGINT should be, though.

[joehuchette]

In my not too exhaustive testing, ab71579 seems to give the expected behavior now. Reopen if I'm wrong!