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<h4 class="subsection">2.6.1 Section input</h4>
<p>When a BFD is opened for reading, the section structures are
created and attached to the BFD.
</p>
<p>Each section has a name which describes the section in the
outside world&mdash;for example, <code>a.out</code> would contain at least
three sections, called <code>.text</code>, <code>.data</code> and <code>.bss</code>.
</p>
<p>Names need not be unique; for example a COFF file may have several
sections named <code>.data</code>.
</p>
<p>Sometimes a BFD will contain more than the &ldquo;natural&rdquo; number of
sections. A back end may attach other sections containing
constructor data, or an application may add a section (using
<code>bfd_make_section</code>) to the sections attached to an already open
BFD. For example, the linker creates an extra section
<code>COMMON</code> for each input file&rsquo;s BFD to hold information about
common storage.
</p>
<p>The raw data is not necessarily read in when
the section descriptor is created. Some targets may leave the
data in place until a <code>bfd_get_section_contents</code> call is
made. Other back ends may read in all the data at once.  For
example, an S-record file has to be read once to determine the
size of the data. An IEEE-695 file doesn&rsquo;t contain raw data in
sections, but data and relocation expressions intermixed, so
the data area has to be parsed to get out the data and
relocations.
</p>


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