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195 <h1>Retrieving data from the server
<a class=
"headerlink" href=
"#retrieving-data-from-the-server" title=
"Permalink to this headline">¶
</a></h1>
196 <div class=
"section" id=
"synopsis">
197 <h2>SYNOPSIS
<a class=
"headerlink" href=
"#synopsis" title=
"Permalink to this headline">¶
</a></h2>
199 <dt>#include
<libmemcached/memcached.h
></dt><dd><p>Compile and link with -lmemcached
</p>
202 <dl class=
"cpp function">
203 <dt id=
"_CPPv422memcached_fetch_resultP12memcached_stP19memcached_result_stP18memcached_return_t">
204 <span id=
"_CPPv322memcached_fetch_resultP12memcached_stP19memcached_result_stP18memcached_return_t"></span><span id=
"_CPPv222memcached_fetch_resultP12memcached_stP19memcached_result_stP18memcached_return_t"></span><span id=
"memcached_fetch_result__memcached_stP.memcached_result_stP.memcached_return_tP"></span><a class=
"reference internal" href=
"memcached_result_st.html#_CPPv419memcached_result_st" title=
"memcached_result_st">memcached_result_st
</a> *
<code class=
"sig-name descname">memcached_fetch_result
</code><span class=
"sig-paren">(
</span><a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st">memcached_st
</a> *
<em>ptr
</em>,
<a class=
"reference internal" href=
"memcached_result_st.html#_CPPv419memcached_result_st" title=
"memcached_result_st">memcached_result_st
</a> *
<em>result
</em>,
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t">memcached_return_t
</a> *
<em>error
</em><span class=
"sig-paren">)
</span><a class=
"headerlink" href=
"#_CPPv422memcached_fetch_resultP12memcached_stP19memcached_result_stP18memcached_return_t" title=
"Permalink to this definition">¶
</a><br /></dt>
207 <dl class=
"cpp function">
208 <dt id=
"_CPPv413memcached_getP12memcached_stPKc6size_tP6size_tP8uint32_tP18memcached_return_t">
209 <span id=
"_CPPv313memcached_getP12memcached_stPKc6size_tP6size_tP8uint32_tP18memcached_return_t"></span><span id=
"_CPPv213memcached_getP12memcached_stPKc6size_tP6size_tP8uint32_tP18memcached_return_t"></span><span id=
"memcached_get__memcached_stP.cCP.s.sP.uint32_tP.memcached_return_tP"></span>char *
<code class=
"sig-name descname">memcached_get
</code><span class=
"sig-paren">(
</span><a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st">memcached_st
</a> *
<em>ptr
</em>,
<em class=
"property">const
</em> char *
<em>key
</em>, size_t
<em>key_length
</em>, size_t *
<em>value_length
</em>, uint32_t *
<em>flags
</em>,
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t">memcached_return_t
</a> *
<em>error
</em><span class=
"sig-paren">)
</span><a class=
"headerlink" href=
"#_CPPv413memcached_getP12memcached_stPKc6size_tP6size_tP8uint32_tP18memcached_return_t" title=
"Permalink to this definition">¶
</a><br /></dt>
212 <dl class=
"cpp function">
213 <dt id=
"_CPPv414memcached_mgetP12memcached_stPPCKcPK6size_t6size_t">
214 <span id=
"_CPPv314memcached_mgetP12memcached_stPPCKcPK6size_t6size_t"></span><span id=
"_CPPv214memcached_mgetP12memcached_stPPCKcPK6size_t6size_t"></span><span id=
"memcached_mget__memcached_stP.cCPCP.sCP.s"></span><a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t">memcached_return_t
</a> <code class=
"sig-name descname">memcached_mget
</code><span class=
"sig-paren">(
</span><a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st">memcached_st
</a> *
<em>ptr
</em>,
<em class=
"property">const
</em> char *
<em class=
"property">const
</em> *
<em>keys
</em>,
<em class=
"property">const
</em> size_t *
<em>key_length
</em>, size_t
<em>number_of_keys
</em><span class=
"sig-paren">)
</span><a class=
"headerlink" href=
"#_CPPv414memcached_mgetP12memcached_stPPCKcPK6size_t6size_t" title=
"Permalink to this definition">¶
</a><br /></dt>
217 <dl class=
"cpp function">
218 <dt id=
"_CPPv420memcached_get_by_keyP12memcached_stPKc6size_tPKc6size_tP6size_tP8uint32_tP18memcached_return_t">
219 <span id=
"_CPPv320memcached_get_by_keyP12memcached_stPKc6size_tPKc6size_tP6size_tP8uint32_tP18memcached_return_t"></span><span id=
"_CPPv220memcached_get_by_keyP12memcached_stPKc6size_tPKc6size_tP6size_tP8uint32_tP18memcached_return_t"></span><span id=
"memcached_get_by_key__memcached_stP.cCP.s.cCP.s.sP.uint32_tP.memcached_return_tP"></span>char *
<code class=
"sig-name descname">memcached_get_by_key
</code><span class=
"sig-paren">(
</span><a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st">memcached_st
</a> *
<em>ptr
</em>,
<em class=
"property">const
</em> char *
<em>group_key
</em>, size_t
<em>group_key_length
</em>,
<em class=
"property">const
</em> char *
<em>key
</em>, size_t
<em>key_length
</em>, size_t *
<em>value_length
</em>, uint32_t *
<em>flags
</em>,
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t">memcached_return_t
</a> *
<em>error
</em><span class=
"sig-paren">)
</span><a class=
"headerlink" href=
"#_CPPv420memcached_get_by_keyP12memcached_stPKc6size_tPKc6size_tP6size_tP8uint32_tP18memcached_return_t" title=
"Permalink to this definition">¶
</a><br /></dt>
222 <dl class=
"cpp function">
223 <dt id=
"_CPPv421memcached_mget_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_t">
224 <span id=
"_CPPv321memcached_mget_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_t"></span><span id=
"_CPPv221memcached_mget_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_t"></span><span id=
"memcached_mget_by_key__memcached_stP.cCP.s.cCPCP.sCP.s"></span><a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t">memcached_return_t
</a> <code class=
"sig-name descname">memcached_mget_by_key
</code><span class=
"sig-paren">(
</span><a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st">memcached_st
</a> *
<em>ptr
</em>,
<em class=
"property">const
</em> char *
<em>group_key
</em>, size_t
<em>group_key_length
</em>,
<em class=
"property">const
</em> char *
<em class=
"property">const
</em> *
<em>keys
</em>,
<em class=
"property">const
</em> size_t *
<em>key_length
</em>, size_t
<em>number_of_keys
</em><span class=
"sig-paren">)
</span><a class=
"headerlink" href=
"#_CPPv421memcached_mget_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_t" title=
"Permalink to this definition">¶
</a><br /></dt>
227 <dl class=
"cpp function">
228 <dt id=
"_CPPv423memcached_fetch_executeP12memcached_stP20memcached_execute_fnPv8uint32_t">
229 <span id=
"_CPPv323memcached_fetch_executeP12memcached_stP20memcached_execute_fnPv8uint32_t"></span><span id=
"_CPPv223memcached_fetch_executeP12memcached_stP20memcached_execute_fnPv8uint32_t"></span><span id=
"memcached_fetch_execute__memcached_stP.memcached_execute_fnP.voidP.uint32_t"></span><a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t">memcached_return_t
</a> <code class=
"sig-name descname">memcached_fetch_execute
</code><span class=
"sig-paren">(
</span><a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st">memcached_st
</a> *
<em>ptr
</em>,
<a class=
"reference internal" href=
"#_CPPv420memcached_execute_fn" title=
"memcached_execute_fn">memcached_execute_fn
</a> *
<em>callback
</em>, void *
<em>context
</em>, uint32_t
<em>number_of_callbacks
</em><span class=
"sig-paren">)
</span><a class=
"headerlink" href=
"#_CPPv423memcached_fetch_executeP12memcached_stP20memcached_execute_fnPv8uint32_t" title=
"Permalink to this definition">¶
</a><br /></dt>
232 <dl class=
"cpp function">
233 <dt id=
"_CPPv422memcached_mget_executeP12memcached_stPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t">
234 <span id=
"_CPPv322memcached_mget_executeP12memcached_stPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t"></span><span id=
"_CPPv222memcached_mget_executeP12memcached_stPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t"></span><span id=
"memcached_mget_execute__memcached_stP.cCPCP.sCP.s.memcached_execute_fnP.voidP.uint32_t"></span><a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t">memcached_return_t
</a> <code class=
"sig-name descname">memcached_mget_execute
</code><span class=
"sig-paren">(
</span><a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st">memcached_st
</a> *
<em>ptr
</em>,
<em class=
"property">const
</em> char *
<em class=
"property">const
</em> *
<em>keys
</em>,
<em class=
"property">const
</em> size_t *
<em>key_length
</em>, size_t
<em>number_of_keys
</em>,
<a class=
"reference internal" href=
"#_CPPv420memcached_execute_fn" title=
"memcached_execute_fn">memcached_execute_fn
</a> *
<em>callback
</em>, void *
<em>context
</em>, uint32_t
<em>number_of_callbacks
</em><span class=
"sig-paren">)
</span><a class=
"headerlink" href=
"#_CPPv422memcached_mget_executeP12memcached_stPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t" title=
"Permalink to this definition">¶
</a><br /></dt>
237 <dl class=
"cpp function">
238 <dt id=
"_CPPv429memcached_mget_execute_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t">
239 <span id=
"_CPPv329memcached_mget_execute_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t"></span><span id=
"_CPPv229memcached_mget_execute_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t"></span><span id=
"memcached_mget_execute_by_key__memcached_stP.cCP.s.cCPCP.sCP.s.memcached_execute_fnP.voidP.uint32_t"></span><a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t">memcached_return_t
</a> <code class=
"sig-name descname">memcached_mget_execute_by_key
</code><span class=
"sig-paren">(
</span><a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st">memcached_st
</a> *
<em>ptr
</em>,
<em class=
"property">const
</em> char *
<em>group_key
</em>, size_t
<em>group_key_length
</em>,
<em class=
"property">const
</em> char *
<em class=
"property">const
</em> *
<em>keys
</em>,
<em class=
"property">const
</em> size_t *
<em>key_length
</em>, size_t
<em>number_of_keys
</em>,
<a class=
"reference internal" href=
"#_CPPv420memcached_execute_fn" title=
"memcached_execute_fn">memcached_execute_fn
</a> *
<em>callback
</em>, void *
<em>context
</em>, uint32_t
<em>number_of_callbacks
</em><span class=
"sig-paren">)
</span><a class=
"headerlink" href=
"#_CPPv429memcached_mget_execute_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t" title=
"Permalink to this definition">¶
</a><br /></dt>
242 <dl class=
"cpp type">
243 <dt id=
"_CPPv420memcached_execute_fn">
244 <span id=
"_CPPv320memcached_execute_fn"></span><span id=
"_CPPv220memcached_execute_fn"></span><span id=
"memcached_execute_fn"></span><em class=
"property">typedef
</em><a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t">memcached_return_t
</a> (*
<code class=
"sig-name descname">memcached_execute_fn
</code>)
<span class=
"sig-paren">(
</span><em class=
"property">const
</em> <a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st">memcached_st
</a> *ptr,
<a class=
"reference internal" href=
"memcached_result_st.html#_CPPv419memcached_result_st" title=
"memcached_result_st">memcached_result_st
</a> *result, void *context
<span class=
"sig-paren">)
</span><a class=
"headerlink" href=
"#_CPPv420memcached_execute_fn" title=
"Permalink to this definition">¶
</a><br /></dt>
248 <div class=
"section" id=
"description">
249 <h2>DESCRIPTION
<a class=
"headerlink" href=
"#description" title=
"Permalink to this headline">¶
</a></h2>
250 <p><a class=
"reference internal" href=
"#_CPPv413memcached_getP12memcached_stPKc6size_tP6size_tP8uint32_tP18memcached_return_t" title=
"memcached_get"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_get()
</span></code></a> is used to fetch an individual value from the server.
251 You must pass in a key and its length to fetch the object. You must supply
252 three pointer variables which will give you the state of the returned
253 object. A
<code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">uint32_t
</span></code> pointer to contain whatever flags you stored
254 with the value, a
<code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">size_t
</span></code> pointer which will be filled with size of of
255 the object, and a
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t"><code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">memcached_return_t
</span></code></a> pointer to hold any error. The
256 object will be returned upon success and NULL will be returned on failure. Any
257 object returned by
<a class=
"reference internal" href=
"#_CPPv413memcached_getP12memcached_stPKc6size_tP6size_tP8uint32_tP18memcached_return_t" title=
"memcached_get"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_get()
</span></code></a> must be released by the caller
259 <p><a class=
"reference internal" href=
"#_CPPv414memcached_mgetP12memcached_stPPCKcPK6size_t6size_t" title=
"memcached_mget"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget()
</span></code></a> is used to select multiple keys at once. For
260 multiple key operations it is always faster to use this function.
261 This function always works asynchronously.
</p>
262 <p>To retrieve data after a successful execution of
<a class=
"reference internal" href=
"#_CPPv414memcached_mgetP12memcached_stPPCKcPK6size_t6size_t" title=
"memcached_mget"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget()
</span></code></a>, you
263 will need to call
<a class=
"reference internal" href=
"#_CPPv422memcached_fetch_resultP12memcached_stP19memcached_result_stP18memcached_return_t" title=
"memcached_fetch_result"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_fetch_result()
</span></code></a>. You should continue to call
264 this function until it returns a NULL (i.e. no more values). If you need to quit
265 in the middle of a
<a class=
"reference internal" href=
"#_CPPv414memcached_mgetP12memcached_stPPCKcPK6size_t6size_t" title=
"memcached_mget"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget()
</span></code></a> call, you can execute a
266 <a class=
"reference internal" href=
"memcached_quit.html#_CPPv414memcached_quitP12memcached_st" title=
"memcached_quit"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_quit()
</span></code></a>, those this is not required.
</p>
267 <p><a class=
"reference internal" href=
"#_CPPv422memcached_fetch_resultP12memcached_stP19memcached_result_stP18memcached_return_t" title=
"memcached_fetch_result"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_fetch_result()
</span></code></a> is used to fetch an individual value from the
268 server.
<a class=
"reference internal" href=
"#_CPPv414memcached_mgetP12memcached_stPPCKcPK6size_t6size_t" title=
"memcached_mget"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget()
</span></code></a> must always be called before using this method.
269 You must pass in a key and its length to fetch the object. You must supply
270 three pointer variables which will give you the state of the returned object.
271 A
<code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">uint32_t
</span></code> pointer to contain whatever flags you stored with the value,
272 a
<code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">size_t
</span></code> pointer which will be filled with size of of the object, and a
273 <a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t"><code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">memcached_return_t
</span></code></a> pointer to hold any error. The object will be
274 returned upon success and NULL will be returned on failure.
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv4N18memcached_return_t13MEMCACHED_ENDE" title=
"MEMCACHED_END"><code class=
"xref cpp cpp-any docutils literal notranslate"><span class=
"pre">MEMCACHED_END
</span></code></a> is
275 returned by the *error value when all objects that have been found have been
276 returned. The final value upon
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv4N18memcached_return_t13MEMCACHED_ENDE" title=
"MEMCACHED_END"><code class=
"xref cpp cpp-any docutils literal notranslate"><span class=
"pre">MEMCACHED_END
</span></code></a> is null.
</p>
277 <p><a class=
"reference internal" href=
"#_CPPv422memcached_fetch_resultP12memcached_stP19memcached_result_stP18memcached_return_t" title=
"memcached_fetch_result"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_fetch_result()
</span></code></a> is used to return a
<a class=
"reference internal" href=
"memcached_result_st.html#_CPPv419memcached_result_st" title=
"memcached_result_st"><code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">memcached_result_st
</span></code></a>
278 structure from a memcached server. The result object is forward compatible
279 with changes to the server. For more information please refer to the
280 <a class=
"reference internal" href=
"memcached_result_st.html#_CPPv419memcached_result_st" title=
"memcached_result_st"><code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">memcached_result_st
</span></code></a> help. This function will dynamically allocate a
281 result structure for you if you do not pass one to the function.
</p>
282 <p><a class=
"reference internal" href=
"#_CPPv423memcached_fetch_executeP12memcached_stP20memcached_execute_fnPv8uint32_t" title=
"memcached_fetch_execute"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_fetch_execute()
</span></code></a> is a callback function for result sets.
283 Instead of returning the results to you for processing, it passes each of the
284 result sets to the list of functions you provide. It passes to the function
285 a
<a class=
"reference internal" href=
"memcached_create.html#_CPPv412memcached_st" title=
"memcached_st"><code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">memcached_st
</span></code></a> that can be cloned for use in the called
286 function (it can not be used directly). It also passes a result set which does
287 not need to be freed. Finally it passes a
"context
". This is just a pointer to
288 a memory reference you supply the calling function. Currently only one value
289 is being passed to each function call. In the future there will be an option
290 to allow this to be an array.
</p>
291 <p><a class=
"reference internal" href=
"#_CPPv422memcached_mget_executeP12memcached_stPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t" title=
"memcached_mget_execute"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget_execute()
</span></code></a> and
<a class=
"reference internal" href=
"#_CPPv429memcached_mget_execute_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t" title=
"memcached_mget_execute_by_key"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget_execute_by_key()
</span></code></a>
292 is similar to
<a class=
"reference internal" href=
"#_CPPv414memcached_mgetP12memcached_stPPCKcPK6size_t6size_t" title=
"memcached_mget"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget()
</span></code></a>, but it may trigger the supplied
293 callbacks with result sets while sending out the queries. If you try to
294 perform a really large multiget with
<a class=
"reference internal" href=
"#_CPPv414memcached_mgetP12memcached_stPPCKcPK6size_t6size_t" title=
"memcached_mget"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget()
</span></code></a> you may
295 encounter a deadlock in the OS kernel (it will fail to write data to the
296 socket because the input buffer is full).
<a class=
"reference internal" href=
"#_CPPv422memcached_mget_executeP12memcached_stPPCKcPK6size_t6size_tP20memcached_execute_fnPv8uint32_t" title=
"memcached_mget_execute"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget_execute()
</span></code></a>
297 solves this problem by processing some of the results before continuing
298 sending out requests. Please note that this function is only available in
299 the binary protocol.
</p>
300 <p><a class=
"reference internal" href=
"#_CPPv420memcached_get_by_keyP12memcached_stPKc6size_tPKc6size_tP6size_tP8uint32_tP18memcached_return_t" title=
"memcached_get_by_key"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_get_by_key()
</span></code></a> and
<a class=
"reference internal" href=
"#_CPPv421memcached_mget_by_keyP12memcached_stPKc6size_tPPCKcPK6size_t6size_t" title=
"memcached_mget_by_key"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget_by_key()
</span></code></a> behave
301 in a similar nature as
<a class=
"reference internal" href=
"#_CPPv413memcached_getP12memcached_stPKc6size_tP6size_tP8uint32_tP18memcached_return_t" title=
"memcached_get"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_get()
</span></code></a> and
<a class=
"reference internal" href=
"#_CPPv414memcached_mgetP12memcached_stPPCKcPK6size_t6size_t" title=
"memcached_mget"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_mget()
</span></code></a>.
302 The difference is that they take a master key that is used for determining
303 which server an object was stored if key partitioning was used for storage.
</p>
304 <p>All of the above functions are not tested when the
305 <a class=
"reference internal" href=
"memcached_behavior.html#_CPPv4N20memcached_behavior_t26MEMCACHED_BEHAVIOR_USE_UDPE" title=
"MEMCACHED_BEHAVIOR_USE_UDP"><code class=
"xref cpp cpp-any docutils literal notranslate"><span class=
"pre">MEMCACHED_BEHAVIOR_USE_UDP
</span></code></a> has been set. Executing any of these
306 functions with this behavior on will result in
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv4N18memcached_return_t23MEMCACHED_NOT_SUPPORTEDE" title=
"MEMCACHED_NOT_SUPPORTED"><code class=
"xref cpp cpp-any docutils literal notranslate"><span class=
"pre">MEMCACHED_NOT_SUPPORTED
</span></code></a> being
307 returned, or for those functions which do not return a
308 <a class=
"reference internal" href=
"memcached_return_t.html#_CPPv418memcached_return_t" title=
"memcached_return_t"><code class=
"xref cpp cpp-type docutils literal notranslate"><span class=
"pre">memcached_return_t
</span></code></a>, the error function parameter will be set to
309 <a class=
"reference internal" href=
"memcached_return_t.html#_CPPv4N18memcached_return_t23MEMCACHED_NOT_SUPPORTEDE" title=
"MEMCACHED_NOT_SUPPORTED"><code class=
"xref cpp cpp-any docutils literal notranslate"><span class=
"pre">MEMCACHED_NOT_SUPPORTED
</span></code></a>.
</p>
311 <div class=
"section" id=
"return-value">
312 <h2>RETURN VALUE
<a class=
"headerlink" href=
"#return-value" title=
"Permalink to this headline">¶
</a></h2>
313 <p>All objects retrieved via
<a class=
"reference internal" href=
"#_CPPv413memcached_getP12memcached_stPKc6size_tP6size_tP8uint32_tP18memcached_return_t" title=
"memcached_get"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_get()
</span></code></a> or
<a class=
"reference internal" href=
"#_CPPv420memcached_get_by_keyP12memcached_stPKc6size_tPKc6size_tP6size_tP8uint32_tP18memcached_return_t" title=
"memcached_get_by_key"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_get_by_key()
</span></code></a>
314 must be freed with
<em class=
"manpage"><a class=
"manpage reference external" href=
"https://linux.die.net/man/3/free">free(
3)
</a></em>.
</p>
315 <p><a class=
"reference internal" href=
"#_CPPv413memcached_getP12memcached_stPKc6size_tP6size_tP8uint32_tP18memcached_return_t" title=
"memcached_get"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_get()
</span></code></a> will return NULL on error.
316 You must look at the value of error to determine what the actual error was.
</p>
317 <p><a class=
"reference internal" href=
"#_CPPv423memcached_fetch_executeP12memcached_stP20memcached_execute_fnPv8uint32_t" title=
"memcached_fetch_execute"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_fetch_execute()
</span></code></a> return
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv4N18memcached_return_t17MEMCACHED_SUCCESSE" title=
"MEMCACHED_SUCCESS"><code class=
"xref cpp cpp-any docutils literal notranslate"><span class=
"pre">MEMCACHED_SUCCESS
</span></code></a> if
318 all keys were successful.
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv4N18memcached_return_t18MEMCACHED_NOTFOUNDE" title=
"MEMCACHED_NOTFOUND"><code class=
"xref cpp cpp-any docutils literal notranslate"><span class=
"pre">MEMCACHED_NOTFOUND
</span></code></a> will be returned if no
319 keys at all were found.
</p>
320 <p><a class=
"reference internal" href=
"#_CPPv422memcached_fetch_resultP12memcached_stP19memcached_result_stP18memcached_return_t" title=
"memcached_fetch_result"><code class=
"xref cpp cpp-func docutils literal notranslate"><span class=
"pre">memcached_fetch_result()
</span></code></a> sets error
321 to
<a class=
"reference internal" href=
"memcached_return_t.html#_CPPv4N18memcached_return_t13MEMCACHED_ENDE" title=
"MEMCACHED_END"><code class=
"xref cpp cpp-any docutils literal notranslate"><span class=
"pre">MEMCACHED_END
</span></code></a> upon successful conclusion.
322 <a class=
"reference internal" href=
"memcached_return_t.html#_CPPv4N18memcached_return_t18MEMCACHED_NOTFOUNDE" title=
"MEMCACHED_NOTFOUND"><code class=
"xref cpp cpp-any docutils literal notranslate"><span class=
"pre">MEMCACHED_NOTFOUND
</span></code></a> will be returned if no keys at all were found.
</p>
324 <div class=
"section" id=
"see-also">
325 <h2>SEE ALSO
<a class=
"headerlink" href=
"#see-also" title=
"Permalink to this headline">¶
</a></h2>
327 <li><p><em class=
"manpage"><a class=
"manpage reference external" href=
"https://linux.die.net/man/1/memcached">memcached(
1)
</a></em></p></li>
328 <li><p><a class=
"reference internal" href=
"../libmemcached.html"><span class=
"doc">C/C++ Client Library for memcached
</span></a></p></li>
329 <li><p><a class=
"reference internal" href=
"memcached_strerror.html"><span class=
"doc">Converting Error Codes to Messages
</span></a></p></li>
340 <div class=
"rst-footer-buttons" role=
"navigation" aria-label=
"footer navigation">
342 <a href=
"memcached_set.html" class=
"btn btn-neutral float-right" title=
"Storing data on the server" accesskey=
"n" rel=
"next">Next
<span class=
"fa fa-arrow-circle-right"></span></a>
345 <a href=
"memcached_create.html" class=
"btn btn-neutral float-left" title=
"Creating and destroying a memcached_st" accesskey=
"p" rel=
"prev"><span class=
"fa fa-arrow-circle-left"></span> Previous
</a>
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"contentinfo">
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