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< p > Library Version 11.2.5.3< / p >
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< th colspan = "3" align = "center" > DB_ENV-> mutex_set_increment()< / th >
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Mutex Methods
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< h2 class = "title" style = "clear: both" > < a id = "mutexset_increment" > < / a > DB_ENV-> mutex_set_increment()< / h2 >
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< pre class = "programlisting" > #include < db.h>
int
DB_ENV-> mutex_set_increment(DB_ENV *dbenv, u_int32_t increment); < / pre >
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Configure the number of additional mutexes to allocate.
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< p >
If an application will allocate mutexes for its own use,
the < code class = "methodname" > DB_ENV-> mutex_set_increment()< / code > method is used to add a
number of mutexes to the default allocation.
< / p >
< p >
Calling the < code class = "methodname" > DB_ENV-> mutex_set_increment()< / code > method discards any value
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previously set using the < a class = "xref" href = "mutexset_max.html" title = "DB_ENV->mutex_set_max()" > DB_ENV-> mutex_set_max()< / a > method.
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The database environment's number of additional mutexes may also be
configured using the environment's < a href = "../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class = "olink" > DB_CONFIG< / a > file. The
syntax of the entry in that file is a single line with the string
"mutex_set_increment", one or more whitespace characters, and the
number of additional mutexes. Because the < a href = "../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class = "olink" > DB_CONFIG< / a > file is
read when the database environment is opened, it will silently
overrule configuration done before that time.
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< p >
The < code class = "methodname" > DB_ENV-> mutex_set_increment()< / code > method configures a database
environment, not only operations performed using the specified
< a class = "link" href = "env.html" title = "Chapter > DB_ENV< / a > handle.
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< p >
The < code class = "methodname" > DB_ENV-> mutex_set_increment()< / code > method may not be called after the
< a class = "xref" href = "envopen.html" title = "DB_ENV->open()" > DB_ENV-> open()< / a > method is
called. If the database environment already exists when
< a class = "xref" href = "envopen.html" title = "DB_ENV->open()" > DB_ENV-> open()< / a > is called, the
information specified to < code class = "methodname" > DB_ENV-> mutex_set_increment()< / code > will be
ignored.
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< p >
The < code class = "methodname" > DB_ENV-> mutex_set_increment()< / code > < span >
< span >
method returns a non-zero error value on failure and 0 on success.
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< h3 class = "title" > < a id = "idp61701200" > < / a > Parameters< / h3 >
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< h4 class = "title" > < a id = "idp61713312" > < / a > increment< / h4 >
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The < span class = "bold" > < strong > increment< / strong > < / span > parameter is the number
of additional mutexes to allocate.
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< h3 class = "title" > < a id = "idp61706008" > < / a > Errors< / h3 >
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The < code class = "methodname" > DB_ENV-> mutex_set_increment()< / code > < span >
< span >
method may fail and return one of the following non-zero errors:
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< h4 class = "title" > < a id = "idp61721552" > < / a > EINVAL< / h4 >
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If the method was called after < a class = "xref" href = "envopen.html" title = "DB_ENV->open()" > DB_ENV-> open()< / a >
was called; or if an invalid flag value or parameter was specified.
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< a class = "link" href = "env.html" title = "Chapter > DB_ENV< / a >
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< h3 class = "title" > < a id = "idp61723680" > < / a > See Also< / h3 >
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< a class = "xref" href = "mutex.html#mutexlist" title = "Mutex Methods" > Mutex Methods< / a >
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