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DbEnv::mutex_stat
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#include &lt;db_cxx.h&gt;

int
DbEnv::mutex_stat(DB_MUTEX_STAT **statp, u_int32_t flags);

int
DbEnv::mutex_stat_print(u_int32_t flags);
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Description: DbEnv::mutex_stat
The DbEnv::mutex_stat method returns the mutex subsystem statistics.
The DbEnv::mutex_stat method creates a statistical structure of type
DB_MUTEX_STAT and copies a pointer to it into a user-specified memory
location.
Statistical structures are stored in allocated memory. If application-specific allocation
routines have been declared (see <a href="../../db4-devel-4.7.25/api_cxx/env_set_alloc.html">DbEnv::set_alloc</a> for more
information), they are used to allocate the memory; otherwise, the
standard C library malloc(3) is used. The caller is
responsible for deallocating the memory. To deallocate the memory, free
the memory reference; references inside the returned memory need not be
individually freed.
The following DB_MUTEX_STAT fields will be filled in:
 
u_int32_t st_mutex_align;<ul compact><li>The mutex alignment, in bytes.</ul>
u_int32_t st_mutex_tas_spins;<ul compact><li>The number of times test-and-set mutexes will spin without blocking.</ul>
int st_mutex_cnt;<ul compact><li>The total number of mutexes configured.</ul>
u_int32_t st_mutex_free;<ul compact><li>The number of mutexes currently available.</ul>
u_int32_t st_mutex_inuse;<ul compact><li>The number of mutexes currently in use.</ul>
u_int32_t st_mutex_inuse_max;<ul compact><li>The maximum number of mutexes ever in use.</ul>
roff_t st_regsize;<ul compact><li>The size of the mutex region, in bytes.</ul>
u_int32_t st_region_wait;<ul compact><li>The number of times that a thread of control was forced to wait before
obtaining the mutex region mutex.</ul>
u_int32_t st_region_nowait;<ul compact><li>The number of times that a thread of control was able to obtain
the mutex region mutex without waiting.</ul>
 
The DbEnv::mutex_stat method may not be called before the <a href="../../db4-devel-4.7.25/api_cxx/env_open.html">DbEnv::open</a> method is called.
The DbEnv::mutex_stat method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.

Parameters 
 flags<ul compact><li>The flags parameter must be set to 0 or
the following value:
 
<a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a><ul compact><li>Reset statistics after returning their values.</ul>
 </ul>
 statp<ul compact><li>The statp parameter references memory into which
a pointer to the allocated statistics structure is copied.</ul> 
 
 Errors
The DbEnv::mutex_stat method
may fail and throw
<a href="../../db4-devel-4.7.25/api_cxx/except_class.html">DbException</a>,
encapsulating one of the following non-zero errors, or return one of
the following non-zero errors:
 
EINVAL<ul compact><li>An
invalid flag value or parameter was specified.</ul>
 
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Description: DbEnv::mutex_stat_print
The DbEnv::mutex_stat_print method displays the
mutex subsystem statistical information, as described for the DbEnv::mutex_stat method.
The information is printed to a specified output channel (see the
<a href="../../db4-devel-4.7.25/api_cxx/env_set_msgfile.html">DbEnv::set_msgfile</a> method for more information), or passed to an
application callback function (see the <a href="../../db4-devel-4.7.25/api_cxx/env_set_msgcall.html">DbEnv::set_msgcall</a> method for
more information).
The DbEnv::mutex_stat_print method may not be called before the <a href="../../db4-devel-4.7.25/api_cxx/env_open.html">DbEnv::open</a> method is called.
The DbEnv::mutex_stat_print method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.

Parameters 
 flags<ul compact><li>The flags parameter must be set to 0 or by bitwise inclusively OR'ing together one
or more of the following values:
 
<a name="DB_STAT_ALL">DB_STAT_ALL</a><ul compact><li>Display all available information.</ul>
<a name="DB_STAT_CLEAR">DB_STAT_CLEAR</a><ul compact><li>Reset statistics after displaying their values.</ul>
 </ul>
 
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 Class
<a href="../../db4-devel-4.7.25/api_cxx/env_class.html">DbEnv</a>
 See Also
<a href="../../db4-devel-4.7.25/api_cxx/env_list.html">Database Environments and Related Methods</a>
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