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<! "@(#)stat.so 10.9 (Sleepycat) 10/28/98">
<!Copyright 1997, 1998 by Sleepycat Software, Inc. All rights reserved.>
<html>
<body bgcolor=white>
<head>
<title>Berkeley DB: DbLockTab::stat</title>
<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
<meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btr
ee,hash,hashing,transaction,transactions,locking,logging,access method,access me
thods,java,C,C++">
</head>
<h1>DbLockTab::stat</h1>
<hr size=1 noshade>
<tt>
<h3>
<pre>
#include <db_cxx.h>
<p>
int
DbLockTab::stat(DB_LOCK_STAT **statp, void *(*db_malloc)(size_t));
</pre>
</h3>
<h1>Description</h1>
The DbLockTab::stat method
creates a statistical structure and copies pointers to it into
user-specified memory locations.
<p>
Statistical structure are created in allocated memory.
If
<b>db_malloc</b> is non-NULL, it is called to allocate the memory,
otherwise, the library function <b>malloc</b>(3)) is used.
The function <b>db_malloc</b> must match the calling conventions of
the <b>malloc</b>(3)) library routine.
Regardless, the caller is responsible for deallocating the returned
memory.
To deallocate the returned memory, free each returned memory pointer;
pointers inside the memory do not need to be individually freed.
<p>
The lock region statistics are stored in a structure of type
DB_LOCK_STAT. The following DB_LOCK_STAT fields will be filled in:
<dl compact>
<dt>u_int32_t st_magic;<dd>The magic number that identifies a file as a lock file.
<dt>u_int32_t st_version;<dd>The version of the lock file type.
<dt>u_int32_t st_refcnt;<dd>The number of references to the region.
<dt>u_int32_t st_regsize;<dd>The size of the region.
<dt>u_int32_t st_maxlocks;<dd>The maximum number of locks possible.
<dt>u_int32_t st_nmodes;<dd>The number of lock modes.
<dt>u_int32_t st_numobjs;<dd>The number of unique objects locked.
<dt>u_int32_t st_nlockers;<dd>The number of unique lockers.
<dt>u_int32_t st_nconflicts;<dd>The total number of locks not immediately available due to conflicts.
<dt>u_int32_t st_nrequests;<dd>The total number of locks requested.
<dt>u_int32_t st_nreleases;<dd>The total number of locks released.
<dt>u_int32_t st_ndeadlocks;<dd>The number of deadlocks detected.
<dt>u_int32_t st_region_wait;<dd>The number of times that a thread of control was forced to wait before
obtaining the region lock.
<dt>u_int32_t st_region_nowait;<dd>The number of times that a thread of control was able to obtain
the region lock without waiting.
</dl>
<p>
The DbLockTab::stat
method either returns <b>errno</b> or throws an exception that
encapsulates an <b>errno</b> on failure, and 0 on success.
<p>
<h1>Errors</h1>
If a fatal error occurs in Berkeley DB, the DbLockTab::stat method may fail and either
return DB_RUNRECOVERY or throw an exception encapsulating DB_RUNRECOVERY,
at which point all subsequent database calls will also fail in the same
way. Methods marked as returning <b>errno</b> will, by default, throw
an exception that encapsulates the error information. The default error
behavior can be changed, see <a href="../../api_cxx/DbException/class.html">DbException</a>.
<p>
The DbLockTab::stat
method may fail and throw an exception
for any of the errors specified for the following Berkeley DB and C library
functions:
abort(3),
fcntl(3),
fprintf(3),
getpid(3),
malloc(3),
and
memset(3).
<p>
<h1>Class</h1>
<a href="../../api_cxx/DbLockTab/class.html">DbLockTab</a>
<p>
<h1>See Also</h1>
<a href="../../api_cxx/DbLockTab/close.html">DbLockTab::close</a>,
<a href="../../api_cxx/DbLockTab/detect.html">DbLockTab::detect</a>,
<a href="../../api_cxx/DbLockTab/get.html">DbLockTab::get</a>,
<a href="../../api_cxx/DbLockTab/id.html">DbLockTab::id</a>,
<a href="../../api_cxx/DbLockTab/open.html">DbLockTab::open</a>,
DbLockTab::stat
<a href="../../api_cxx/DbLockTab/unlink.html">DbLockTab::unlink</a>
and
<a href="../../api_cxx/DbLockTab/vec.html">DbLockTab::vec</a>.
</tt>
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