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<h1>Atomic Operations<br>
<small>
[<a class="el" href="group__APR.html">Apache Portability Runtime library</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"><a class="el" href="group__apr__errno.html#ga0">apr_status_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga0">apr_atomic_init</a> (<a class="el" href="group__apr__pools.html#ga0">apr_pool_t</a> *p)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">apr_uint32_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga1">apr_atomic_read32</a> (volatile apr_uint32_t *mem)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga2">apr_atomic_set32</a> (volatile apr_uint32_t *mem, apr_uint32_t val)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">apr_uint32_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga3">apr_atomic_add32</a> (volatile apr_uint32_t *mem, apr_uint32_t val)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga4">apr_atomic_sub32</a> (volatile apr_uint32_t *mem, apr_uint32_t val)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">apr_uint32_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga5">apr_atomic_inc32</a> (volatile apr_uint32_t *mem)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga6">apr_atomic_dec32</a> (volatile apr_uint32_t *mem)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">apr_uint32_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga7">apr_atomic_cas32</a> (volatile apr_uint32_t *mem, apr_uint32_t with, apr_uint32_t cmp)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">apr_uint32_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga8">apr_atomic_xchg32</a> (volatile apr_uint32_t *mem, apr_uint32_t val)</td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void * </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__atomic.html#ga9">apr_atomic_casptr</a> (volatile void **mem, void *with, const void *cmp)</td></tr>
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<hr><h2>Function Documentation</h2>
<a class="anchor" name="ga3" doxytag="apr_atomic.h::apr_atomic_add32"></a><p>
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<td class="md" nowrap valign="top">apr_uint32_t apr_atomic_add32 </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">volatile apr_uint32_t * </td>
<td class="mdname" nowrap> <em>mem</em>, </td>
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<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>apr_uint32_t </td>
<td class="mdname" nowrap> <em>val</em></td>
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<td class="md"></td>
<td class="md">) </td>
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atomically add 'val' to an apr_uint32_t <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>pointer to the object </td></tr>
<tr><td valign="top"></td><td valign="top"><em>val</em> </td><td>amount to add </td></tr>
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</dl>
<dl compact><dt><b>Returns:</b></dt><dd>old value pointed to by mem </dd></dl>
</td>
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<a class="anchor" name="ga7" doxytag="apr_atomic.h::apr_atomic_cas32"></a><p>
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<td class="md" nowrap valign="top">apr_uint32_t apr_atomic_cas32 </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">volatile apr_uint32_t * </td>
<td class="mdname" nowrap> <em>mem</em>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>apr_uint32_t </td>
<td class="mdname" nowrap> <em>with</em>, </td>
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<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>apr_uint32_t </td>
<td class="mdname" nowrap> <em>cmp</em></td>
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<td class="md"></td>
<td class="md">) </td>
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compare an apr_uint32_t's value with 'cmp'. If they are the same swap the value with 'with' <dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>mem</em> </td><td>pointer to the value </td></tr>
<tr><td valign="top"></td><td valign="top"><em>with</em> </td><td>what to swap it with </td></tr>
<tr><td valign="top"></td><td valign="top"><em>cmp</em> </td><td>the value to compare it to </td></tr>
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</dl>
<dl compact><dt><b>Returns:</b></dt><dd>the old value of *mem </dd></dl>
</td>
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<a class="anchor" name="ga9" doxytag="apr_atomic.h::apr_atomic_casptr"></a><p>
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<td class="md" nowrap valign="top">void* apr_atomic_casptr </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">volatile void ** </td>
<td class="mdname" nowrap> <em>mem</em>, </td>
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<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>void * </td>
<td class="mdname" nowrap> <em>with</em>, </td>
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<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>const void * </td>
<td class="mdname" nowrap> <em>cmp</em></td>
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<td class="md"></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
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<p>
compare the pointer's value with cmp. If they are the same swap the value with 'with' <dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>mem</em> </td><td>pointer to the pointer </td></tr>
<tr><td valign="top"></td><td valign="top"><em>with</em> </td><td>what to swap it with </td></tr>
<tr><td valign="top"></td><td valign="top"><em>cmp</em> </td><td>the value to compare it to </td></tr>
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</dl>
<dl compact><dt><b>Returns:</b></dt><dd>the old value of the pointer </dd></dl>
</td>
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<a class="anchor" name="ga6" doxytag="apr_atomic.h::apr_atomic_dec32"></a><p>
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<td class="md" nowrap valign="top">int apr_atomic_dec32 </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">volatile apr_uint32_t * </td>
<td class="mdname1" valign="top" nowrap> <em>mem</em> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap></td>
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</td>
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<p>
atomically decrement an apr_uint32_t by 1 <dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>mem</em> </td><td>pointer to the atomic value </td></tr>
</table>
</dl>
<dl compact><dt><b>Returns:</b></dt><dd>zero if the value becomes zero on decrement, otherwise non-zero </dd></dl>
</td>
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<a class="anchor" name="ga5" doxytag="apr_atomic.h::apr_atomic_inc32"></a><p>
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<td class="md" nowrap valign="top">apr_uint32_t apr_atomic_inc32 </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">volatile apr_uint32_t * </td>
<td class="mdname1" valign="top" nowrap> <em>mem</em> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap></td>
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</td>
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<p>
atomically increment an apr_uint32_t by 1 <dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>mem</em> </td><td>pointer to the object </td></tr>
</table>
</dl>
<dl compact><dt><b>Returns:</b></dt><dd>old value pointed to by mem </dd></dl>
</td>
</tr>
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<a class="anchor" name="ga0" doxytag="apr_atomic.h::apr_atomic_init"></a><p>
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<td class="md" nowrap valign="top"><a class="el" href="group__apr__errno.html#ga0">apr_status_t</a> apr_atomic_init </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="mdname1" valign="top" nowrap> <em>p</em> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap></td>
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this function is required on some platforms to initialize the atomic operation's internal structures <dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>p</em> </td><td>pool </td></tr>
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</dl>
<dl compact><dt><b>Returns:</b></dt><dd>APR_SUCCESS on successful completion </dd></dl>
</td>
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<a class="anchor" name="ga1" doxytag="apr_atomic.h::apr_atomic_read32"></a><p>
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<td class="md" nowrap valign="top">apr_uint32_t apr_atomic_read32 </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">volatile apr_uint32_t * </td>
<td class="mdname1" valign="top" nowrap> <em>mem</em> </td>
<td class="md" valign="top"> ) </td>
<td class="md" nowrap></td>
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<p>
atomically read an apr_uint32_t from memory <dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>mem</em> </td><td>the pointer </td></tr>
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</dl>
</td>
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<a class="anchor" name="ga2" doxytag="apr_atomic.h::apr_atomic_set32"></a><p>
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<td class="md" nowrap valign="top">void apr_atomic_set32 </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">volatile apr_uint32_t * </td>
<td class="mdname" nowrap> <em>mem</em>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>apr_uint32_t </td>
<td class="mdname" nowrap> <em>val</em></td>
</tr>
<tr>
<td class="md"></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
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atomically set an apr_uint32_t in memory <dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>mem</em> </td><td>pointer to the object </td></tr>
<tr><td valign="top"></td><td valign="top"><em>val</em> </td><td>value that the object will assume </td></tr>
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<a class="anchor" name="ga4" doxytag="apr_atomic.h::apr_atomic_sub32"></a><p>
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<td class="md" nowrap valign="top">void apr_atomic_sub32 </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">volatile apr_uint32_t * </td>
<td class="mdname" nowrap> <em>mem</em>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>apr_uint32_t </td>
<td class="mdname" nowrap> <em>val</em></td>
</tr>
<tr>
<td class="md"></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
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<p>
atomically subtract 'val' from an apr_uint32_t <dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>mem</em> </td><td>pointer to the object </td></tr>
<tr><td valign="top"></td><td valign="top"><em>val</em> </td><td>amount to subtract </td></tr>
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</dl>
</td>
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<a class="anchor" name="ga8" doxytag="apr_atomic.h::apr_atomic_xchg32"></a><p>
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<td class="md" nowrap valign="top">apr_uint32_t apr_atomic_xchg32 </td>
<td class="md" valign="top">( </td>
<td class="md" nowrap valign="top">volatile apr_uint32_t * </td>
<td class="mdname" nowrap> <em>mem</em>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>apr_uint32_t </td>
<td class="mdname" nowrap> <em>val</em></td>
</tr>
<tr>
<td class="md"></td>
<td class="md">) </td>
<td class="md" colspan="2"></td>
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<p>
exchange an apr_uint32_t's value with 'val'. <dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>mem</em> </td><td>pointer to the value </td></tr>
<tr><td valign="top"></td><td valign="top"><em>val</em> </td><td>what to swap it with </td></tr>
</table>
</dl>
<dl compact><dt><b>Returns:</b></dt><dd>the old value of *mem </dd></dl>
</td>
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