Surprizing little documentation on setting this up, so I'm sure this is a setup problem.
Steps to reproduce: Open terminal (p4.exe in PATH) type p4 [RET]
Hangs indefinitely. When I issue commands from emacs (ie p4 edit [file] it eventually comes back with
Perforce client error:
Connect to server failed; check $P4PORT.
TCP connect to perforce failed.
perforce: host unknown.
The error message that is displayed when called from emacs points in the right direction, p4 can't find your perforce server (the default is perforce, that's where the perforce: host unknown comes from.
Make sure to either specify -p for your call to p4 or set the environment variable P4PORT. Beware, despite the name, P4PORT includes the hostname of the perforce server.
p4 -p serverhost:1666
I'm not sure why p4 would hang indefinitely on the CLI and return after some time when called from emacs.