This function works only on the controlling terminal of the Emacs
session; to relinquish control of other tty devices, use
-@code{suspend-tty} (@pxref{Visibility of Frames}). If the Emacs
-session uses more than one terminal device, you will need to delete
-the frames on all the other devices before suspending Emacs, otherwise
-this function signals an error.
+@code{suspend-tty} (see below). If the Emacs session uses more than
+one terminal device, you will need to delete the frames on all the
+other devices before suspending Emacs, otherwise this function signals
+an error.
If @var{string} is non-@code{nil}, its characters are sent to be read
as terminal input by Emacs's superior shell. The characters in
specifies the variable, and the other ``duplicates'' are ignored.
@end defvar
-@defun environment &optional frame
-This is a convenience function that returns the value of
-@code{process-environment} after removing unset and duplicate
-variables from it. The optional argument @var{frame}, which should be
-a frame, means return the list of environment variables in effect for
-that frame. The value this function returns is a copy, so changing it
-will have no effect on the environment variables passed to
-subprocesses.
-@end defun
-
@defvar initial-environment
This variable holds the list of environment variables Emacs inherited
from its parent process. It is computed during startup, see