Errno location

errno_location.cr

ERNNOS = Hash(Pointer(Int32), Int32).new(0)

enum Errno
  def self.pointer
    {% if flag?(:netbsd) || flag?(:openbsd) || flag?(:android) %}
      LibC.__errno
    {% elsif flag?(:linux) || flag?(:dragonfly) %}
      LibC.__errno_location
    {% elsif flag?(:wasi) %}
      raise NotImplementedError.new("Errno.pointer")
    {% elsif flag?(:darwin) || flag?(:freebsd) %}
      LibC.__error
    {% elsif flag?(:win32) %}
      raise NotImplementedError.new("Errno.pointer")
    {% end %}
  end
end

def print_errno_info(name)
  puts "#{name}: #{Thread.current} errno at #{Errno.pointer}"
  ERNNOS[Errno.pointer] += 1
end

count = ARGV[0]?.try(&.to_i) || 10
count.times do |i|
  Thread.new do
    print_errno_info(i)
  end
end

print_errno_info("main")

print "Distribution: "
ERNNOS.values.join(STDOUT, ", ")
puts