title: undefined function :wx_object.start/3
body: <p>I have tried to install ErLang on my Mac 64bit, Capitan, I've tried to install it via brew, but when I try to run :observer.start I get this error:</p>
  
  <pre><code>** (UndefinedFunctionError) undefined function :wx_object.start/3 (module :wx_object is not available)
      :wx_object.start(:observer_wx, [], [])
      observer_wx.erl:72: :observer_wx.start/0
  </code></pre>
  
  <p>I also tried to install erLang otp 18.3 using erlang solutions, but I got the same error.</p>
  
  <p>Any idea?</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>If I try to start the observer directly from the Erlang shell: </p>
  
  <pre><code>^CiMac:~ Apple$ erl 
  Erlang/OTP 18 [erts-7.3] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]
  
  Eshell V7.3  (abort with ^G)
  1&gt; observer:start().
  ** exception error: undefined function wx_object:start/3
       in function  observer_wx:start/0 (observer_wx.erl, line 72)
  </code></pre>
  
  <p><strong>EDIT2</strong></p>
  
  <pre><code>iMac:~ Apple$ brew info erlang
  erlang: stable 18.3 (bottled), HEAD
  Programming language for highly scalable real-time systems
  https://www.erlang.org/
  /usr/local/Cellar/erlang/18.3 (7,489 files, 273.8M)
    Poured from bottle on 2016-05-13 at 12:24:59
  From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/erlang.rb
  ==&gt; Dependencies
  Build: autoconf ✔, automake ✔, libtool ✔
  Required: openssl ✔
  Recommended: wxmac ✔
  Optional: fop ✘
  ==&gt; Options
  --with-dirty-schedulers
      Enable experimental dirty schedulers
  --with-fop
      Build with fop support
  --with-native-libs
      Enable native library compilation
  --without-docs
      Do not install documentation
  --without-hipe
      Disable building hipe; fails on various OS X systems
  --without-wxmac
      Build without wxmac support
  --HEAD
      Install HEAD version
  ==&gt; Caveats
  Man pages can be found in:
    /usr/local/opt/erlang/lib/erlang/man
  
  Access them with `erl -man`, or add this directory to MANPATH.
  iMac:~ Apple$ which erl
  /opt/local/bin/erl
  </code></pre>
  
  <p>erl at brew info is:
      /usr/local/Cellar/erlang/18.3
  but, which erl is:
      /opt/local/bin/erl
  which points to <code>/opt/local/lib/erlang/bin/erl</code></p>
  
  <p>if I started <code>/usr/local/Cellar/erlang/18.3/bin/erl</code> observer will work! </p>
  
  <p>so, I deleted the alias by mouse and I:</p>
  
  <pre><code>sudo ln -s /usr/local/Cellar/erlang/18.3/lib/erlang/bin/erl /opt/local/bin/erl
  </code></pre>
  
  <p>but I am not sure about <code>/opt/local/lib/erlang/bin/erl</code> how it was created..
  any way, it works now..</p>