mult_ios with "exec"

[Stephane Chazelas <stephane.chazelas@xxxxxxxxx>]

zsh -c 'exec 3> a 3> b; echo never reached'

That command hangs.

strace shows zsh stuck on:

rt_sigsuspend([INT])

Same with >>, not with < or <> (though I suppose mult_ios
doesn't apply to <> or is equivalent to < there).

Note:

$ zsh -c 'eval exec 3> a 3> b; echo test >&3'
zsh:1: 3: bad file descriptor

(same with other shells (except the Bourne shell)).

zsh -c 'exec 3> >(tee a > b); echo reached'

is OK.

-- 
Stephane