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| <h3 class="section">8.3 Basic Types For C<tt>++</tt></h3> |
| |
| <p><< the examples that follow are based on a01.C >> |
| |
| <p>C<tt>++</tt> adds two more builtin types to the set defined for C. These are |
| the unknown type and the vtable record type. The unknown type, type |
| 16, is defined in terms of itself like the void type. |
| |
| <p>The vtable record type, type 17, is defined as a structure type and |
| then as a structure tag. The structure has four fields: delta, index, |
| pfn, and delta2. pfn is the function pointer. |
| |
| <p><< In boilerplate $vtbl_ptr_type, what are the fields delta, |
| index, and delta2 used for? >> |
| |
| <p>This basic type is present in all C<tt>++</tt> programs even if there are no |
| virtual methods defined. |
| |
| <pre class="display"> .stabs "struct_name:sym_desc(type)type_def(17)=type_desc(struct)struct_bytes(8) |
| elem_name(delta):type_ref(short int),bit_offset(0),field_bits(16); |
| elem_name(index):type_ref(short int),bit_offset(16),field_bits(16); |
| elem_name(pfn):type_def(18)=type_desc(ptr to)type_ref(void), |
| bit_offset(32),field_bits(32); |
| elem_name(delta2):type_def(short int);bit_offset(32),field_bits(16);;" |
| N_LSYM, NIL, NIL |
| </pre> |
| <pre class="smallexample"> .stabs "$vtbl_ptr_type:t17=s8 |
| delta:6,0,16;index:6,16,16;pfn:18=*15,32,32;delta2:6,32,16;;" |
| ,128,0,0,0 |
| </pre> |
| <pre class="display"> .stabs "name:sym_dec(struct tag)type_ref($vtbl_ptr_type)",N_LSYM,NIL,NIL,NIL |
| </pre> |
| <pre class="example"> .stabs "$vtbl_ptr_type:T17",128,0,0,0 |
| </pre> |
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