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<h3 class="section">8.6 Method Definition</h3>

<p>The class definition shown above declares Ameth.  The C<tt>++</tt> source below
defines Ameth:

<pre class="example">     int
     baseA::Ameth(int in, char other)
     {
             return in;
     };
</pre>
   <p>This method definition yields three stabs following the code of the
method.  One stab describes the method itself and following two describe
its parameters.  Although there is only one formal argument all methods
have an implicit argument which is the <code>this</code> pointer.  The <code>this</code>
pointer is a pointer to the object on which the method was called.  Note
that the method name is mangled to encode the class name and argument
types.  Name mangling is described in the <span class="sc">arm</span> (<cite>The Annotated
C++ Reference Manual</cite>, by Ellis and Stroustrup, <span class="sc">isbn</span>
0-201-51459-1); <samp><span class="file">gpcompare.texi</span></samp> in Cygnus GCC distributions
describes the differences between GNU mangling and <span class="sc">arm</span>
mangling. 
<!-- FIXME: Use @xref, especially if this is generally installed in the -->
<!-- info tree. -->
<!-- FIXME: This information should be in a net release, either of GCC or -->
<!-- GDB.  But gpcompare.texi doesn't seem to be in the FSF GCC. -->

<pre class="example">     .stabs "name:symbol_descriptor(global function)return_type(int)",
             N_FUN, NIL, NIL, code_addr_of_method_start
     
     .stabs "Ameth__5baseAic:F1",36,0,0,_Ameth__5baseAic
</pre>
   <p>Here is the stab for the <code>this</code> pointer implicit argument.  The
name of the <code>this</code> pointer is always <code>this</code>.  Type 19, the
<code>this</code> pointer is defined as a pointer to type 20, <code>baseA</code>,
but a stab defining <code>baseA</code> has not yet been emitted.  Since the
compiler knows it will be emitted shortly, here it just outputs a cross
reference to the undefined symbol, by prefixing the symbol name with
&lsquo;<samp><span class="samp">xs</span></samp>&rsquo;.

<pre class="example">     .stabs "name:sym_desc(register param)type_def(19)=
             type_desc(ptr to)type_ref(baseA)=
             type_desc(cross-reference to)baseA:",N_RSYM,NIL,NIL,register_number
     
     .stabs "this:P19=*20=xsbaseA:",64,0,0,8
</pre>
   <p>The stab for the explicit integer argument looks just like a parameter
to a C function.  The last field of the stab is the offset from the
argument pointer, which in most systems is the same as the frame
pointer.

<pre class="example">     .stabs "name:sym_desc(value parameter)type_ref(int)",
             N_PSYM,NIL,NIL,offset_from_arg_ptr
     
     .stabs "in:p1",160,0,0,72
</pre>
   <p>&lt;&lt; The examples that follow are based on A1.C &gt;&gt;

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