Weird function in Emacs 24.4: x-display-pixel-width

When you use two or more monitors, Mac, Emacs 24.4, actually it's Emacs 24.3.50.3.

You will find weird behavior about the function: x-display-pixel-width.

In Emacs 24.4, the function return the width of your all monitors.

This is the description in Emacs 24.4:

x-display-pixel-width is a built-in function in `C source code'.
(x-display-pixel-width &optional TERMINAL)
Return the width in pixels of the Nextstep display TERMINAL.
The optional argument TERMINAL specifies which display to ask about.
TERMINAL should be a terminal object, a frame or a display name (a string).
If omitted or nil, that stands for the selected frame's display.
On "multi-monitor" setups this refers to the pixel width for all
physical monitors associated with TERMINAL.  To get information for
each physical monitor, use `display-monitor-attributes-list'.

This is the description in Emacs 24.3:

x-display-pixel-width is a built-in function in `C source code'.
(x-display-pixel-width &optional DISPLAY)
Return the width in pixels of the Nextstep display DISPLAY.
The optional argument DISPLAY specifies which display to ask about.
DISPLAY should be either a frame, a display name (a string), or terminal ID.
If omitted or nil, that stands for the selected frame's display.

Install Emacs from homebrew, Mac user only

For brand new install, just run this 4 lines in shell:

brew install --cocoa --srgb emacs
ln -s /usr/local/Cellar/emacs/24.3/Emacs.app /Applications/Emacs.app
ln -s /usr/local/Cellar/emacs/24.3/bin/emacs /usr/local/bin
ln -s /usr/local/Cellar/emacs/24.3/bin/emacsclient /usr/local/bin

Please make sure that "/usr/local/bin" before "/usr/bin" in your $PATH