How to set font size in emacs 24 installed in gentoo

Question

I found emacs 24 can not use c-x c-+ and c-- to change the font size.

once i input c-x c-+ the horizontal bar below text region shows (Emacs-Lisp +1 h1-p) and the number after + symbol increases if i press c-+ further. also in the minibar, it says

Use +,-,0 for further adjustment

however, the font size in the text region doesn't change at all

also I followed How to set the font size in Emacs?, it seems not working either.

in emacs wiki, it doesn't give detail solutions either... http://www.emacswiki.org/emacs/SetFonts

my emacs version is

GNU Emacs 24.3.1
Copyright (C) 2013 Free Software Foundation, Inc.
GNU Emacs comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of Emacs
under the terms of the GNU General Public License.
For more information about these matters, see the file named COPYING.

and system

Linux mybox 3.10.7-gentoo #1 SMP Mon Sep 2 16:48:35 Local time zone must be set--see zic m x86_64 AMD E-450 APU with Radeon(tm) HD Graphics AuthenticAMD GNU/Linux

thanks in advance!

Answer 1

ok, I finally solved the problem, it is due to a missing flag during compile. based on http://wiki.gentoo.org/wiki/Project:Emacs/GNU_Emacs_developer_guide

gconf    Use gconf to read the system font name (Emacs 23 and above).
gsettings    Use gsettings (glib) to read the system font name (Emacs 24 and above).
gconf    Use gconf to read the system font name (Emacs 23 and above).

but they are not enabled as default compiling.

so i add

echo  'app-editors/emacs xft gsettings gconf' >> /etc/portage/package.use

and then recompile & build emacs.

finally we have

$ ldd `which emacs` | grep libXft
libXft.so.2 => /usr/lib64/libXft.so.2 (0x00007f9c1eed6000)