Getting the exit status from the command at the head of a pipeline in dash vs. bash

gistfile1.txt

DASH
----
Not actually supported by POSIX alone. Googled from http://www.spinics.net/lists/dash/msg00327.html:

$ exec 3>&1 # duplicate original stdout
$ result=$(
  exec 4>&1 >&3 3>&- # move cmd subst stdout, and restore original
  { ./main.sh; echo $? >&4 # run command, and record its status
  } | head -n 3)
$ echo $result # status from ./main.sh
$ exec 3>&-

BASH
----
$ ./main.sh | head -n 3
$ echo ${PIPESTATUS[0]} # nice bash extension

whoa