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<h1>Pool Debugging functions.<br>
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[<a class="el" href="group__apr__pools.html">Memory Pool Functions</a>]</small>
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<tr><td colspan="2"><br><h2>Functions</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__PoolDebug.html#ga0">apr_pool_join</a> (<a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> *p, <a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> *sub)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top"><a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="group__PoolDebug.html#ga1">apr_pool_find</a> (const void *mem)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">apr_size_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group__PoolDebug.html#ga2">apr_pool_num_bytes</a> (<a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> *p, int recurse)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__PoolDebug.html#ga3">apr_pool_lock</a> (<a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> *pool, int flag)</td></tr>
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<hr><a name="_details"></a><h2>Detailed Description</h2>
pools have nested lifetimes -- sub_pools are destroyed when the parent pool is cleared. We allow certain liberties with operations on things such as tables (and on other structures in a more general sense) where we allow the caller to insert values into a table which were not allocated from the table's pool. The table's data will remain valid as long as all the pools from which its values are allocated remain valid.<p>
For example, if B is a sub pool of A, and you build a table T in pool B, then it's safe to insert data allocated in A or B into T (because B lives at most as long as A does, and T is destroyed when B is cleared/destroyed). On the other hand, if S is a table in pool A, it is safe to insert data allocated in A into S, but it is *not safe* to insert data allocated from B into S... because B can be cleared/destroyed before A is (which would leave dangling pointers in T's data structures).<p>
In general we say that it is safe to insert data into a table T if the data is allocated in any ancestor of T's pool. This is the basis on which the APR_POOL_DEBUG code works -- it tests these ancestor relationships for all data inserted into tables. APR_POOL_DEBUG also provides tools (apr_pool_find, and apr_pool_is_ancestor) for other folks to implement similar restrictions for their own data structures.<p>
However, sometimes this ancestor requirement is inconvenient -- sometimes we're forced to create a sub pool (such as through apr_sub_req_lookup_uri), and the sub pool is guaranteed to have the same lifetime as the parent pool. This is a guarantee implemented by the *caller*, not by the pool code. That is, the caller guarantees they won't destroy the sub pool individually prior to destroying the parent pool.<p>
In this case the caller must call <a class="el" href="group__PoolDebug.html#ga0">apr_pool_join()</a> to indicate this guarantee to the APR_POOL_DEBUG code. There are a few examples spread through the standard modules.<p>
These functions are only implemented when <a class="el" href="group__apr__pools.html#ga32">APR_POOL_DEBUG</a> is set. <hr><h2>Function Documentation</h2>
<a class="anchor" name="ga1" doxytag="apr_pools.h::apr_pool_find"></a><p>
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<td class="md" nowrap valign="top"><a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a>* apr_pool_find </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">const void * </td>
<td class="mdname1" valign="top" nowrap> <em>mem</em> </td>
<td class="md" valign="top"> ) </td>
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Find a pool from something allocated in it. <dl compact><dt><b>Parameters:</b></dt><dd>
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<tr><td valign="top"></td><td valign="top"><em>mem</em> </td><td>The thing allocated in the pool </td></tr>
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<dl compact><dt><b>Returns:</b></dt><dd>The pool it is allocated in </dd></dl>
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<a class="anchor" name="ga0" doxytag="apr_pools.h::apr_pool_join"></a><p>
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<td class="md" nowrap valign="top">void apr_pool_join </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top"><a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> * </td>
<td class="mdname" nowrap> <em>p</em>, </td>
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<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap><a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> * </td>
<td class="mdname" nowrap> <em>sub</em></td>
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<td class="md"></td>
<td class="md">) </td>
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Guarantee that a subpool has the same lifetime as the parent. <dl compact><dt><b>Parameters:</b></dt><dd>
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<tr><td valign="top"></td><td valign="top"><em>p</em> </td><td>The parent pool </td></tr>
<tr><td valign="top"></td><td valign="top"><em>sub</em> </td><td>The subpool </td></tr>
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<a class="anchor" name="ga3" doxytag="apr_pools.h::apr_pool_lock"></a><p>
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<td class="md" nowrap valign="top">void apr_pool_lock </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top"><a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> * </td>
<td class="mdname" nowrap> <em>pool</em>, </td>
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<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>int </td>
<td class="mdname" nowrap> <em>flag</em></td>
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<td class="md"></td>
<td class="md">) </td>
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Lock a pool <dl compact><dt><b>Parameters:</b></dt><dd>
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<tr><td valign="top"></td><td valign="top"><em>pool</em> </td><td>The pool to lock </td></tr>
<tr><td valign="top"></td><td valign="top"><em>flag</em> </td><td>The flag </td></tr>
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<a class="anchor" name="ga2" doxytag="apr_pools.h::apr_pool_num_bytes"></a><p>
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<td class="md" nowrap valign="top">apr_size_t apr_pool_num_bytes </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top"><a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> * </td>
<td class="mdname" nowrap> <em>p</em>, </td>
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<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>int </td>
<td class="mdname" nowrap> <em>recurse</em></td>
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<td class="md"></td>
<td class="md">) </td>
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Report the number of bytes currently in the pool <dl compact><dt><b>Parameters:</b></dt><dd>
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<tr><td valign="top"></td><td valign="top"><em>p</em> </td><td>The pool to inspect </td></tr>
<tr><td valign="top"></td><td valign="top"><em>recurse</em> </td><td>Recurse/include the subpools' sizes </td></tr>
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<dl compact><dt><b>Returns:</b></dt><dd>The number of bytes </dd></dl>
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<hr size="1"><address style="align: right;"><small>Generated on Sun Mar 20 19:52:27 2005 for Apache Portable Runtime by
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