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| Next: <a href="Mini-Symbols.html#Mini-Symbols" accesskey="n" rel="next">Mini Symbols</a>, Previous: <a href="Reading-Symbols.html#Reading-Symbols" accesskey="p" rel="prev">Reading Symbols</a>, Up: <a href="Symbols.html#Symbols" accesskey="u" rel="up">Symbols</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="BFD-Index.html#BFD-Index" title="Index" rel="index">Index</a>]</p> |
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| <a name="Writing-symbols"></a> |
| <h4 class="subsection">2.7.2 Writing symbols</h4> |
| <p>Writing of a symbol table is automatic when a BFD open for |
| writing is closed. The application attaches a vector of |
| pointers to pointers to symbols to the BFD being written, and |
| fills in the symbol count. The close and cleanup code reads |
| through the table provided and performs all the necessary |
| operations. The BFD output code must always be provided with an |
| “owned” symbol: one which has come from another BFD, or one |
| which has been created using <code>bfd_make_empty_symbol</code>. Here is an |
| example showing the creation of a symbol table with only one element: |
| </p> |
| <div class="example"> |
| <pre class="example"> #include "sysdep.h" |
| #include "bfd.h" |
| int main (void) |
| { |
| bfd *abfd; |
| asymbol *ptrs[2]; |
| asymbol *new; |
| |
| abfd = bfd_openw ("foo","a.out-sunos-big"); |
| bfd_set_format (abfd, bfd_object); |
| new = bfd_make_empty_symbol (abfd); |
| new->name = "dummy_symbol"; |
| new->section = bfd_make_section_old_way (abfd, ".text"); |
| new->flags = BSF_GLOBAL; |
| new->value = 0x12345; |
| |
| ptrs[0] = new; |
| ptrs[1] = 0; |
| |
| bfd_set_symtab (abfd, ptrs, 1); |
| bfd_close (abfd); |
| return 0; |
| } |
| |
| ./makesym |
| nm foo |
| 00012345 A dummy_symbol |
| </pre></div> |
| |
| <p>Many formats cannot represent arbitrary symbol information; for |
| instance, the <code>a.out</code> object format does not allow an |
| arbitrary number of sections. A symbol pointing to a section |
| which is not one of <code>.text</code>, <code>.data</code> or <code>.bss</code> cannot |
| be described. |
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