Unable to share csh history between terminals

[Mike Clarke]

After googling how to do this I ended up with the following in ~/.cshrc

alias postcmd 'history -S; history -M'
set history = 1000
set histdup = erase
set savehist = (1000 merge)

But the results were disastrous, instead of sharing the history each terminal opened 
with a fresh empty history and wiped out the previous .history file.

What am I doing wrong?

When I remove the postcmd alias I revert to the previous arrangement where each 
terminal window starts with the contents of .history and stores its entire history back 
into the file on exit.

-- 
Mike Clarke