open ::STDOUT, ">& $call_fds[1]" or fail_log("dup for fd1");
open ::STDERR, ">& $call_fds[2]" or fail_log("dup for fd2");
close_call_fds();
open ::STDOUT, ">& $call_fds[1]" or fail_log("dup for fd1");
open ::STDERR, ">& $call_fds[2]" or fail_log("dup for fd2");
close_call_fds();