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<h1>DB->fd</h1>
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<h3><pre>
#include <db.h>
<p>
int
DB->fd(DB *db, int *fdp);
</pre></h3>
<h1>Description</h1>
<p>The DB->fd method
copies a file descriptor representative of the underlying database into
the memory to which <b>fdp</b> refers. A file descriptor referring to
the same file will be returned to all processes that call
<a href="../api_c/db_open.html">DB->open</a> with the same <b>file</b> argument. This file
descriptor may be safely used as an argument to the <b>fcntl</b>(2)
and <b>flock</b>(2) locking functions. The file descriptor is not
necessarily associated with any of the underlying files actually used
by the access method.
<p>The DB->fd method only supports a coarse-grained form of locking.
Applications should use the lock manager where possible.
<p>The DB->fd method returns a non-zero error value on failure and 0 on success.
<h1>Errors</h1>
<p>The DB->fd method may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions.
If a catastrophic error has occurred, the DB->fd method may fail and
return <a href="../ref/program/errorret.html#DB_RUNRECOVERY">DB_RUNRECOVERY</a>,
in which case all subsequent Berkeley DB calls will fail in the same way.
<h1>Class</h1>
<a href="../api_c/db_class.html">DB</a>
<h1>See Also</h1>
<a href="../api_c/db_list.html">Databases and Related Methods</a>
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