libjulia_sigint_demo.py

from ctypes import c_char_p, c_void_p
import ctypes
import os
import subprocess


def juliainfo():
    out = subprocess.check_output(
        ["julia", "-e", """
        using Libdl
        println(Base.Sys.BINDIR)
        println(Libdl.dlpath(string("lib", splitext(Base.julia_exename())[1])))
        println(unsafe_string(Base.JLOptions().image_file))
        """],
        universal_newlines=True)
    return out.split("\n")[:3]


def demo():
    try:
        input("Please hit Ctrl-C\n")
    except KeyboardInterrupt:
        print("Got a KeyboardInterrupt")

    bindir, libjulia_path, image_file = juliainfo()
    print("Base.Sys.BINDIR =", bindir)
    print("libjulia_path =", libjulia_path)
    if not os.path.exists(libjulia_path):
        raise RuntimeError('Julia library ("libjulia") not found! {}'
                           .format(libjulia_path))

    # Handle to libjulia without GIL:
    dll = ctypes.CDLL(libjulia_path, ctypes.RTLD_GLOBAL)
    try:
        jl_init_with_image = dll.jl_init_with_image
    except AttributeError:
        try:
            jl_init_with_image = dll.jl_init_with_image__threading
        except AttributeError:
            raise RuntimeError(
                "No libjulia entrypoint found! (tried jl_init_with_image"
                " and jl_init_with_image__threading)")
    jl_init_with_image.argtypes = [c_char_p, c_char_p]
    jl_init_with_image = jl_init_with_image

    dll.jl_eval_string.argtypes = [c_char_p]
    dll.jl_eval_string.restype = c_void_p

    print("calling jl_init_with_image({}, {})".format(bindir, image_file))
    jl_init_with_image(bindir.encode("utf-8"), image_file.encode("utf-8"))
    print("seems to work...")

    dll.jl_eval_string(b"""
    try
        println("Please hit Ctrl-C")
        readline(stdin)
    catch err
        @show typeof(err)
        display(stacktrace(catch_backtrace()))
    end
    """)
    print()
    print()

    try:
        input("Please hit Ctrl-C\n")
    except KeyboardInterrupt:
        print("Got a KeyboardInterrupt")


if __name__ == "__main__":
    demo()