windows 下,报这个错误:RuntimeError (RuCaptcha: D:/ruby/Ruby21-x64/lib/ruby/gems/2.1.0/gems/posix-spawn-0.3.11/lib/posix/spawn.rb:164: warning: cannot close fd before spawn 查找原因如下: pid, stdin, stdout, stderr = POSIX::Spawn.popen4(command) Process.waitpid(pid) err = stderr.read 初学 rails,不懂,求解释