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| <a name="Questions-and-Anomalies"></a> |
| <h2 class="appendix">Appendix E Questions and Anomalies</h2> |
| |
| <ul> |
| <li> For GNU C stabs defining local and global variables (<code>N_LSYM</code> and |
| <code>N_GSYM</code>), the desc field is supposed to contain the source |
| line number on which the variable is defined. In reality the desc |
| field is always 0. (This behavior is defined in <samp>dbxout.c</samp> and |
| putting a line number in desc is controlled by ‘<samp>#ifdef |
| WINNING_GDB</samp>’, which defaults to false). GDB supposedly uses this |
| information if you say ‘<samp>list <var>var</var></samp>’. In reality, <var>var</var> can |
| be a variable defined in the program and GDB says ‘<samp>function |
| <var>var</var> not defined</samp>’. |
| |
| </li><li> In GNU C stabs, there seems to be no way to differentiate tag types: |
| structures, unions, and enums (symbol descriptor ‘<samp>T</samp>’) and typedefs |
| (symbol descriptor ‘<samp>t</samp>’) defined at file scope from types defined locally |
| to a procedure or other more local scope. They all use the <code>N_LSYM</code> |
| stab type. Types defined at procedure scope are emitted after the |
| <code>N_RBRAC</code> of the preceding function and before the code of the |
| procedure in which they are defined. This is exactly the same as |
| types defined in the source file between the two procedure bodies. |
| GDB over-compensates by placing all types in block #1, the block for |
| symbols of file scope. This is true for default, ‘<samp>-ansi</samp>’ and |
| ‘<samp>-traditional</samp>’ compiler options. (Bugs gcc/1063, gdb/1066.) |
| |
| </li><li> What ends the procedure scope? Is it the proc block’s <code>N_RBRAC</code> or the |
| next <code>N_FUN</code>? (I believe its the first.) |
| </li></ul> |
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