crystal_c_call_timeout.cr

require "socket"
lib C
  # In C: double cos(double x)
  fun sleep(value : UInt32) : UInt32
end

spawn {
  loop {
    TCPSocket.new("facebook.com",80,0.1,0.1).close
    STDOUT.print "."
  }
}

loop {
  puts "sleeping"
  Fiber.yield
  C.sleep(1) # or replace with sleep(1)
}

output.log

$ crystal bad.cr 
sleeping
sleeping
sleeping
Unhandled exception in spawn: connect timed out (IO::Timeout)
  from /usr/share/crystal/src/socket/tcp_socket.cr:75:15 in 'initialize'
  from /usr/share/crystal/src/socket/tcp_socket.cr:27:3 in 'new'
  from bad.cr:9:5 in '->'
  from /usr/share/crystal/src/fiber.cr:255:3 in 'run'
  from /usr/share/crystal/src/fiber.cr:48:34 in '->'
  from ???
sleeping