--- a/libinterp/corefcn/mex.cc	Tue May 16 17:23:09 2017 -0400
+++ b/libinterp/corefcn/mex.cc	Tue May 16 18:32:46 2017 -0400
@@ -3084,8 +3084,8 @@
                                 F77_INT& nrhs, mxArray **prhs);
 
 octave_value_list
-call_mex (bool have_fmex, void *f, const octave_value_list& args,
-          int nargout_arg, octave_mex_function *curr_mex_fcn)
+call_mex (octave_mex_function& mex_fcn, const octave_value_list& args,
+          int nargout_arg)
 {
   octave_quit ();
 
@@ -3109,16 +3109,18 @@
   // Save old mex pointer.
   frame.protect_var (mex_context);
 
-  mex context (curr_mex_fcn);
+  mex context (&mex_fcn);
 
   for (int i = 0; i < nargin; i++)
     argin[i] = context.make_value (args(i));
 
   mex_context = &context;
 
-  if (have_fmex)
+  void *mex_fcn_ptr = mex_fcn.mex_fcn_ptr ();
+
+  if (mex_fcn.is_fmex ())
     {
-      fmex_fptr fcn = reinterpret_cast<fmex_fptr> (f);
+      fmex_fptr fcn = reinterpret_cast<fmex_fptr> (mex_fcn_ptr);
 
       F77_INT tmp_nargout = nargout;
       F77_INT tmp_nargin = nargin;
@@ -3127,7 +3129,7 @@
     }
   else
     {
-      cmex_fptr fcn = reinterpret_cast<cmex_fptr> (f);
+      cmex_fptr fcn = reinterpret_cast<cmex_fptr> (mex_fcn_ptr);
 
       fcn (nargout, argout, nargin, argin);
     }

--- a/libinterp/octave-value/ov-mex-fcn.cc	Tue May 16 17:23:09 2017 -0400
+++ b/libinterp/octave-value/ov-mex-fcn.cc	Tue May 16 18:32:46 2017 -0400
@@ -45,36 +45,36 @@
 octave_mex_function::octave_mex_function
   (void *fptr, bool fmex, const octave::dynamic_library& shl,
    const std::string& nm)
-  : octave_function (nm), mex_fcn_ptr (fptr), exit_fcn_ptr (0),
-    have_fmex (fmex), sh_lib (shl)
+  : octave_function (nm), m_mex_fcn_ptr (fptr), m_exit_fcn_ptr (0),
+    m_is_fmex (fmex), m_sh_lib (shl)
 {
   mark_fcn_file_up_to_date (time_parsed ());
 
   std::string file_name = fcn_file_name ();
 
-  system_fcn_file
+  m_is_system_fcn_file
     = (! file_name.empty ()
        && Voct_file_dir == file_name.substr (0, Voct_file_dir.length ()));
 }
 
 octave_mex_function::~octave_mex_function (void)
 {
-  if (exit_fcn_ptr)
-    (*exit_fcn_ptr) ();
+  if (m_exit_fcn_ptr)
+    (*m_exit_fcn_ptr) ();
 
-  octave::dynamic_loader::remove_mex (my_name, sh_lib);
+  octave::dynamic_loader::remove_mex (my_name, m_sh_lib);
 }
 
 std::string
 octave_mex_function::fcn_file_name (void) const
 {
-  return sh_lib.file_name ();
+  return m_sh_lib.file_name ();
 }
 
 octave::sys::time
 octave_mex_function::time_parsed (void) const
 {
-  return sh_lib.time_loaded ();
+  return m_sh_lib.time_loaded ();
 }
 
 octave_value_list
@@ -124,8 +124,8 @@
 
 // FIXME: shouldn't this declaration be a header file somewhere?
 extern octave_value_list
-call_mex (bool have_fmex, void *f, const octave_value_list& args,
-          int nargout, octave_mex_function *curr_mex_fcn);
+call_mex (octave_mex_function& curr_mex_fcn, const octave_value_list& args,
+          int nargout);
 
 octave_value_list
 octave_mex_function::do_multi_index_op (int nargout,
@@ -144,7 +144,7 @@
 
   profile_data_accumulator::enter<octave_mex_function> block (profiler, *this);
 
-  retval = call_mex (have_fmex, mex_fcn_ptr, args, nargout, this);
+  retval = call_mex (*this, args, nargout);
 
   return retval;
 }

--- a/libinterp/octave-value/ov-mex-fcn.h	Tue May 16 17:23:09 2017 -0400
+++ b/libinterp/octave-value/ov-mex-fcn.h	Tue May 16 18:32:46 2017 -0400
@@ -44,10 +44,11 @@
 public:
 
   octave_mex_function (void)
-    : mex_fcn_ptr (), exit_fcn_ptr (), have_fmex (), sh_lib (),
-      t_checked (), system_fcn_file () { }
+    : m_mex_fcn_ptr (), m_exit_fcn_ptr (), m_is_fmex (), m_sh_lib (),
+      m_time_checked (), m_is_system_fcn_file () { }
 
-  octave_mex_function (void *fptr, bool fmex, const octave::dynamic_library& shl,
+  octave_mex_function (void *fptr, bool fmex,
+                       const octave::dynamic_library& shl,
                        const std::string& nm = "");
 
   // No copying!
@@ -73,15 +74,18 @@
 
   const octave_function * function_value (bool = false) const { return this; }
 
-  void mark_fcn_file_up_to_date (const octave::sys::time& t) { t_checked = t; }
+  void mark_fcn_file_up_to_date (const octave::sys::time& t)
+  {
+    m_time_checked = t;
+  }
 
   std::string fcn_file_name (void) const;
 
   octave::sys::time time_parsed (void) const;
 
-  octave::sys::time time_checked (void) const { return t_checked; }
+  octave::sys::time time_checked (void) const { return m_time_checked; }
 
-  bool is_system_fcn_file (void) const { return system_fcn_file; }
+  bool is_system_fcn_file (void) const { return m_is_system_fcn_file; }
 
   bool is_builtin_function (void) const { return false; }
 
@@ -90,29 +94,32 @@
   octave_value_list
   do_multi_index_op (int nargout, const octave_value_list& args);
 
-  void atexit (void (*fcn) (void)) { exit_fcn_ptr = fcn; }
+  void atexit (void (*fcn) (void)) { m_exit_fcn_ptr = fcn; }
+
+  octave::dynamic_library get_shlib (void) const { return m_sh_lib; }
 
-  octave::dynamic_library get_shlib (void) const
-  { return sh_lib; }
+  void *mex_fcn_ptr (void) const { return m_mex_fcn_ptr; }
+
+  bool is_fmex (void) const { return m_is_fmex; }
 
 private:
 
-  void *mex_fcn_ptr;
+  void *m_mex_fcn_ptr;
 
-  void (*exit_fcn_ptr) (void);
+  void (*m_exit_fcn_ptr) (void);
 
-  bool have_fmex;
+  bool m_is_fmex;
 
-  octave::dynamic_library sh_lib;
+  octave::dynamic_library m_sh_lib;
 
   // The time the file was last checked to see if it needs to be
   // parsed again.
-  mutable octave::sys::time t_checked;
+  mutable octave::sys::time m_time_checked;
 
   // True if this function came from a file that is considered to be a
   // system function.  This affects whether we check the time stamp
   // on the file to see if it has changed.
-  bool system_fcn_file;
+  bool m_is_system_fcn_file;
 
   DECLARE_OV_TYPEID_FUNCTIONS_AND_DATA
 };