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<a href="#id3286431" class="shortcut">Description</a></nobr></td></tr>
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<a href="#glib-Memory-Slices.description" class="shortcut">Description</a>
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<div class="refentry" lang="en">
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<a name="glib-Memory-Slices"></a><div class="titlepage"></div>
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<div class="refnamediv"><table width="100%"><tr>
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<a name="id3286227"></a><span class="refentrytitle">Memory Slices</span>
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<p>Memory Slices — efficient way to allocate groups of equal-sized chunks of memory</p>
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<h2><span class="refentrytitle"><a name="glib-Memory-Slices.top_of_page"></a>Memory Slices</span></h2>
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<p>Memory Slices — efficient way to allocate groups of equal-sized chunks of memory</p>
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<td valign="top" align="right"></td>
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</tr></table></div>
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<div class="refsynopsisdiv">
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<a name="glib-Memory-Slices.synopsis"></a><h2>Synopsis</h2>
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<pre class="synopsis">
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#include <glib.h>
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<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> <a class="link" href="glib-Memory-Slices.html#g-slice-alloc">g_slice_alloc</a> (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size);
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<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0">g_slice_alloc0</a> (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size);
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<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> <a class="link" href="glib-Memory-Slices.html#g-slice-copy">g_slice_copy</a> (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> mem_block);
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void <a class="link" href="glib-Memory-Slices.html#g-slice-free1">g_slice_free1</a> (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> mem_block);
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void <a class="link" href="glib-Memory-Slices.html#g-slice-free-chain-with-offset">g_slice_free_chain_with_offset</a> (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> mem_chain,
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<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> next_offset);
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-new">g_slice_new</a> (type)
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-new0">g_slice_new0</a> (type)
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-dup">g_slice_dup</a> (type, mem)
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-free">g_slice_free</a> (type, mem)
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-free-chain">g_slice_free_chain</a> (type, mem_chain, next)
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<a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> <a class="link" href="glib-Memory-Slices.html#g-slice-alloc" title="g_slice_alloc ()">g_slice_alloc</a> (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size);
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<a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0" title="g_slice_alloc0 ()">g_slice_alloc0</a> (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size);
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<a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> <a class="link" href="glib-Memory-Slices.html#g-slice-copy" title="g_slice_copy ()">g_slice_copy</a> (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gconstpointer" title="gconstpointer">gconstpointer</a> mem_block);
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void <a class="link" href="glib-Memory-Slices.html#g-slice-free1" title="g_slice_free1 ()">g_slice_free1</a> (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> mem_block);
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void <a class="link" href="glib-Memory-Slices.html#g-slice-free-chain-with-offset" title="g_slice_free_chain_with_offset ()">g_slice_free_chain_with_offset</a> (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> mem_chain,
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<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> next_offset);
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-new" title="g_slice_new()">g_slice_new</a> (type)
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-new0" title="g_slice_new0()">g_slice_new0</a> (type)
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-dup" title="g_slice_dup()">g_slice_dup</a> (type, mem)
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-free" title="g_slice_free()">g_slice_free</a> (type, mem)
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#define <a class="link" href="glib-Memory-Slices.html#g-slice-free-chain" title="g_slice_free_chain()">g_slice_free_chain</a> (type, mem_chain, next)
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<div class="refsect1" lang="en">
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<a name="id3286431"></a><h2>Description</h2>
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<a name="glib-Memory-Slices.description"></a><h2>Description</h2>
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Memory slices provide a space-efficient and multi-processing scalable
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way to allocate equal-sized pieces of memory, just like the original
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memory-waste, scalability and performance problems.
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To achieve these goals, the slice allocator uses a sophisticated,
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To achieve these goals, the slice allocator uses a sophisticated,
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layered design that has been inspired by Bonwick's slab allocator
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<sup>[<a name="id3286464" href="#ftn.id3286464" class="footnote">6</a>]</sup>.
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It uses <code class="function">posix_memalign()</code> to optimize allocations of many equally-sized
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chunks, and has per-thread free lists (the so-called magazine layer)
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to quickly satisfy allocation requests of already known structure sizes.
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This is accompanied by extra caching logic to keep freed memory around
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for some time before returning it to the system. Memory that is unused
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due to alignment constraints is used for cache colorization (random
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distribution of chunk addresses) to improve CPU cache utilization. The
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caching layer of the slice allocator adapts itself to high lock contention
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<sup>[<a name="id3337918" href="#ftn.id3337918" class="footnote">6</a>]</sup>.
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It uses <code class="function">posix_memalign()</code> to optimize allocations of many equally-sized
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chunks, and has per-thread free lists (the so-called magazine layer)
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to quickly satisfy allocation requests of already known structure sizes.
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This is accompanied by extra caching logic to keep freed memory around
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for some time before returning it to the system. Memory that is unused
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due to alignment constraints is used for cache colorization (random
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distribution of chunk addresses) to improve CPU cache utilization. The
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caching layer of the slice allocator adapts itself to high lock contention
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to improve scalability.
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The slice allocator can allocate blocks as small as two pointers, and
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unlike <code class="function">malloc()</code>, it does not reserve extra space per block. For large block
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sizes, <a class="link" href="glib-Memory-Slices.html#g-slice-new"><code class="function">g_slice_new()</code></a> and <a class="link" href="glib-Memory-Slices.html#g-slice-alloc"><code class="function">g_slice_alloc()</code></a> will automatically delegate to the
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unlike <code class="function">malloc()</code>, it does not reserve extra space per block. For large block
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sizes, <a class="link" href="glib-Memory-Slices.html#g-slice-new" title="g_slice_new()"><code class="function">g_slice_new()</code></a> and <a class="link" href="glib-Memory-Slices.html#g-slice-alloc" title="g_slice_alloc ()"><code class="function">g_slice_alloc()</code></a> will automatically delegate to the
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system <code class="function">malloc()</code> implementation. For newly written code it is recommended
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to use the new <code class="literal">g_slice</code> API instead of <a class="link" href="glib-Memory-Allocation.html#g-malloc"><code class="function">g_malloc()</code></a> and
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friends, as long as objects are not resized during their lifetime and the
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to use the new <code class="literal">g_slice</code> API instead of <a class="link" href="glib-Memory-Allocation.html#g-malloc" title="g_malloc ()"><code class="function">g_malloc()</code></a> and
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friends, as long as objects are not resized during their lifetime and the
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object size used at allocation time is still available when freeing.
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<div class="example">
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<a name="id3286586"></a><p class="title"><b>Example 15. Using the slice allocator</b></p>
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<a name="id3338038"></a><p class="title"><b>Example 15. Using the slice allocator</b></p>
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<div class="example-contents"><pre class="programlisting">
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gchar *mem[10000];
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/* Allocate 10000 blocks. */
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for (i = 0; i < 10000; i++)
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mem[i] = g_slice_alloc (50);
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/* Fill in the memory with some junk. */
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for (j = 0; j < 50; j++)
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mem[i][j] = i * j;
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/* Now free all of the blocks. */
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for (i = 0; i < 10000; i++)
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<br class="example-break">
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<div class="refsect1" lang="en">
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<a name="id3286631"></a><h2>Details</h2>
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<a name="glib-Memory-Slices.details"></a><h2>Details</h2>
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<div class="refsect2" lang="en">
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<a name="id3286641"></a><h3>
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<a name="g-slice-alloc"></a>g_slice_alloc ()</h3>
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<a class="indexterm" name="id3286656"></a><pre class="programlisting"><a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> g_slice_alloc (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size);</pre>
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<a name="g-slice-alloc"></a><h3>g_slice_alloc ()</h3>
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<pre class="programlisting"><a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> g_slice_alloc (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size);</pre>
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Allocates a block of memory from the slice allocator.
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The block adress handed out can be expected to be aligned
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<col align="left" valign="top">
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td>the number of bytes to allocate
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<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
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<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
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<td>a pointer to the allocated memory block
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<p class="since">Since 2.10
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<p class="since">Since 2.10</p>
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<div class="refsect2" lang="en">
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<a name="id3286752"></a><h3>
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<a name="g-slice-alloc0"></a>g_slice_alloc0 ()</h3>
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<a class="indexterm" name="id3286767"></a><pre class="programlisting"><a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> g_slice_alloc0 (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size);</pre>
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<a name="g-slice-alloc0"></a><h3>g_slice_alloc0 ()</h3>
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<pre class="programlisting"><a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> g_slice_alloc0 (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size);</pre>
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Allocates a block of memory via <a class="link" href="glib-Memory-Slices.html#g-slice-alloc"><code class="function">g_slice_alloc()</code></a>
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Allocates a block of memory via <a class="link" href="glib-Memory-Slices.html#g-slice-alloc" title="g_slice_alloc ()"><code class="function">g_slice_alloc()</code></a>
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and initialize the returned memory to 0.
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Note that the underlying slice allocation mechanism can
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be changed with the <a class="link" href="glib-running.html#G_SLICE" title="G_SLICE">G_SLICE=always-malloc</a>
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<col align="left" valign="top">
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td>the number of bytes to allocate
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<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
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<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
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<td>a pointer to the allocated block
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<p class="since">Since 2.10
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<p class="since">Since 2.10</p>
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<div class="refsect2" lang="en">
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<a name="id3286852"></a><h3>
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<a name="g-slice-copy"></a>g_slice_copy ()</h3>
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<a class="indexterm" name="id3286868"></a><pre class="programlisting"><a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> g_slice_copy (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> mem_block);</pre>
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<a name="g-slice-copy"></a><h3>g_slice_copy ()</h3>
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<pre class="programlisting"><a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> g_slice_copy (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gconstpointer" title="gconstpointer">gconstpointer</a> mem_block);</pre>
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Allocates a block of memory from the slice allocator and copies
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<em class="parameter"><code>block_size</code></em> bytes into it from <em class="parameter"><code>mem_block</code></em>.
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<col align="left" valign="top">
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td>the number of bytes to allocate
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<td><p><span class="term"><em class="parameter"><code>mem_block</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>mem_block</code></em> :</span></p></td>
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<td>the memory to copy
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<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
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<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
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<td>a pointer to the allocated memory block
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<p class="since">Since 2.14
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<p class="since">Since 2.14</p>
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<div class="refsect2" lang="en">
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<a name="id3286968"></a><h3>
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<a name="g-slice-free1"></a>g_slice_free1 ()</h3>
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<a class="indexterm" name="id3286982"></a><pre class="programlisting">void g_slice_free1 (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> mem_block);</pre>
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<a name="g-slice-free1"></a><h3>g_slice_free1 ()</h3>
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<pre class="programlisting">void g_slice_free1 (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> mem_block);</pre>
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Frees a block of memory. The memory must have been allocated via
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<a class="link" href="glib-Memory-Slices.html#g-slice-alloc"><code class="function">g_slice_alloc()</code></a> or <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0"><code class="function">g_slice_alloc0()</code></a>
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<a class="link" href="glib-Memory-Slices.html#g-slice-alloc" title="g_slice_alloc ()"><code class="function">g_slice_alloc()</code></a> or <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0" title="g_slice_alloc0 ()"><code class="function">g_slice_alloc0()</code></a>
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and the <em class="parameter"><code>block_size</code></em> has to match the size specified upon allocation.
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Note that the exact release behaviour can be changed with the
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<a class="link" href="glib-running.html#G_DEBUG" title="G_DEBUG">G_DEBUG=gc-friendly</a> environment variable,
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<col align="left" valign="top">
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td>the size of the block
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<td><p><span class="term"><em class="parameter"><code>mem_block</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>mem_block</code></em> :</span></p></td>
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<td>a pointer to the block to free
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<p class="since">Since 2.10
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<p class="since">Since 2.10</p>
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<div class="refsect2" lang="en">
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<a name="id3287104"></a><h3>
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<a name="g-slice-free-chain-with-offset"></a>g_slice_free_chain_with_offset ()</h3>
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<a class="indexterm" name="id3287119"></a><pre class="programlisting">void g_slice_free_chain_with_offset (<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> mem_chain,
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<a class="link" href="glib-Basic-Types.html#gsize">gsize</a> next_offset);</pre>
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<a name="g-slice-free-chain-with-offset"></a><h3>g_slice_free_chain_with_offset ()</h3>
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<pre class="programlisting">void g_slice_free_chain_with_offset (<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> block_size,
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<a class="link" href="glib-Basic-Types.html#gpointer" title="gpointer">gpointer</a> mem_chain,
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<a class="link" href="glib-Basic-Types.html#gsize" title="gsize">gsize</a> next_offset);</pre>
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Frees a linked list of memory blocks of structure type <em class="parameter"><code>type</code></em>.
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The memory blocks must be equal-sized, allocated via
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<a class="link" href="glib-Memory-Slices.html#g-slice-alloc"><code class="function">g_slice_alloc()</code></a> or <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0"><code class="function">g_slice_alloc0()</code></a>
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and linked together by a <em class="parameter"><code>next</code></em> pointer (similar to <a class="link" href="glib-Singly-Linked-Lists.html#GSList"><span class="type">GSList</span></a>). The offset
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<a class="link" href="glib-Memory-Slices.html#g-slice-alloc" title="g_slice_alloc ()"><code class="function">g_slice_alloc()</code></a> or <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0" title="g_slice_alloc0 ()"><code class="function">g_slice_alloc0()</code></a>
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and linked together by a <em class="parameter"><code>next</code></em> pointer (similar to <a class="link" href="glib-Singly-Linked-Lists.html#GSList" title="GSList"><span class="type">GSList</span></a>). The offset
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of the <em class="parameter"><code>next</code></em> field in each block is passed as third argument.
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Note that the exact release behaviour can be changed with the
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<a class="link" href="glib-running.html#G_DEBUG" title="G_DEBUG">G_DEBUG=gc-friendly</a> environment variable,
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<col align="left" valign="top">
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>block_size</code></em> :</span></p></td>
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<td>the size of the blocks
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<td><p><span class="term"><em class="parameter"><code>mem_chain</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>mem_chain</code></em> :</span></p></td>
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<td> a pointer to the first block of the chain
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<td><p><span class="term"><em class="parameter"><code>next_offset</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>next_offset</code></em> :</span></p></td>
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<td>the offset of the <em class="parameter"><code>next</code></em> field in the blocks
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<p class="since">Since 2.10
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<p class="since">Since 2.10</p>
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<div class="refsect2" lang="en">
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<a name="id3287290"></a><h3>
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<a name="g-slice-new"></a>g_slice_new()</h3>
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<a class="indexterm" name="id3287305"></a><pre class="programlisting">#define g_slice_new(type)</pre>
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<a name="g-slice-new"></a><h3>g_slice_new()</h3>
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<pre class="programlisting">#define g_slice_new(type)</pre>
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A convenience macro to allocate a block of memory from the slice allocator.
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It calls <a class="link" href="glib-Memory-Slices.html#g-slice-alloc"><code class="function">g_slice_alloc()</code></a> with <code class="literal">sizeof (<em class="parameter"><code>type</code></em>)</code> and casts
343
the returned pointer to a pointer of the given type, avoiding a type cast
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It calls <a class="link" href="glib-Memory-Slices.html#g-slice-alloc" title="g_slice_alloc ()"><code class="function">g_slice_alloc()</code></a> with <code class="literal">sizeof (<em class="parameter"><code>type</code></em>)</code> and casts
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the returned pointer to a pointer of the given type, avoiding a type cast
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in the source code.
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Note that the underlying slice allocation mechanism can
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be changed with the <a class="link" href="glib-running.html#G_SLICE" title="G_SLICE">G_SLICE=always-malloc</a>
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<col align="left" valign="top">
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<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
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<td>the type to allocate, typically a structure name
358
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
330
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
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331
<td>a pointer to the allocated block, cast to a pointer to <em class="parameter"><code>type</code></em>.
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<p class="since">Since 2.10
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<p class="since">Since 2.10</p>
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339
<div class="refsect2" lang="en">
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<a name="id3287398"></a><h3>
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<a name="g-slice-new0"></a>g_slice_new0()</h3>
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<a class="indexterm" name="id3287413"></a><pre class="programlisting">#define g_slice_new0(type)</pre>
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<a name="g-slice-new0"></a><h3>g_slice_new0()</h3>
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<pre class="programlisting">#define g_slice_new0(type)</pre>
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343
A convenience macro to allocate a block of memory from the slice allocator
376
and set the memory to 0. It calls <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0"><code class="function">g_slice_alloc0()</code></a> with
377
<code class="literal">sizeof (<em class="parameter"><code>type</code></em>)</code> and casts the returned pointer to a pointer
344
and set the memory to 0. It calls <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0" title="g_slice_alloc0 ()"><code class="function">g_slice_alloc0()</code></a> with
345
<code class="literal">sizeof (<em class="parameter"><code>type</code></em>)</code> and casts the returned pointer to a pointer
378
346
of the given type, avoiding a type cast in the source code.
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347
Note that the underlying slice allocation mechanism can
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be changed with the <a class="link" href="glib-running.html#G_SLICE" title="G_SLICE">G_SLICE=always-malloc</a>
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<col align="left" valign="top">
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<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
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<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
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356
<td>the type to allocate, typically a structure name
392
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
360
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
393
361
<td>a pointer to the allocated block, cast to a pointer to <em class="parameter"><code>type</code></em>.
398
<p class="since">Since 2.10
366
<p class="since">Since 2.10</p>
404
369
<div class="refsect2" lang="en">
405
<a name="id3287506"></a><h3>
406
<a name="g-slice-dup"></a>g_slice_dup()</h3>
407
<a class="indexterm" name="id3287520"></a><pre class="programlisting">#define g_slice_dup(type, mem)</pre>
370
<a name="g-slice-dup"></a><h3>g_slice_dup()</h3>
371
<pre class="programlisting">#define g_slice_dup(type, mem)</pre>
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373
A convenience macro to duplicate a block of memory using the slice allocator.
410
It calls <a class="link" href="glib-Memory-Slices.html#g-slice-copy"><code class="function">g_slice_copy()</code></a> with <code class="literal">sizeof (<em class="parameter"><code>type</code></em>)</code> and casts
411
the returned pointer to a pointer of the given type, avoiding a type cast
374
It calls <a class="link" href="glib-Memory-Slices.html#g-slice-copy" title="g_slice_copy ()"><code class="function">g_slice_copy()</code></a> with <code class="literal">sizeof (<em class="parameter"><code>type</code></em>)</code> and casts
375
the returned pointer to a pointer of the given type, avoiding a type cast
412
376
in the source code.
413
377
Note that the underlying slice allocation mechanism can
414
378
be changed with the <a class="link" href="glib-running.html#G_SLICE" title="G_SLICE">G_SLICE=always-malloc</a>
418
382
<col align="left" valign="top">
421
<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
385
<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
422
386
<td>the type to duplicate, typically a structure name
426
<td><p><span class="term"><em class="parameter"><code>mem</code></em> :</span></p></td>
390
<td><p><span class="term"><em class="parameter"><code>mem</code></em> :</span></p></td>
427
391
<td>the memory to copy into the allocated block
431
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
395
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
432
396
<td>a pointer to the allocated block, cast to a pointer to <em class="parameter"><code>type</code></em>.
437
<p class="since">Since 2.14
401
<p class="since">Since 2.14</p>
443
404
<div class="refsect2" lang="en">
444
<a name="id3287627"></a><h3>
445
<a name="g-slice-free"></a>g_slice_free()</h3>
446
<a class="indexterm" name="id3287642"></a><pre class="programlisting">#define g_slice_free(type, mem)</pre>
405
<a name="g-slice-free"></a><h3>g_slice_free()</h3>
406
<pre class="programlisting">#define g_slice_free(type, mem)</pre>
448
408
A convenience macro to free a block of memory that has been allocated
449
from the slice allocator. It calls <a class="link" href="glib-Memory-Slices.html#g-slice-free1"><code class="function">g_slice_free1()</code></a> using
409
from the slice allocator. It calls <a class="link" href="glib-Memory-Slices.html#g-slice-free1" title="g_slice_free1 ()"><code class="function">g_slice_free1()</code></a> using
450
410
<code class="literal">sizeof (type)</code> as the block size.
451
411
Note that the exact release behaviour can be changed with the
452
412
<a class="link" href="glib-running.html#G_DEBUG" title="G_DEBUG">G_DEBUG=gc-friendly</a> environment variable,
456
416
<col align="left" valign="top">
459
<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
419
<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
460
420
<td>the type of the block to free, typically a structure name
464
<td><p><span class="term"><em class="parameter"><code>mem</code></em> :</span></p></td>
424
<td><p><span class="term"><em class="parameter"><code>mem</code></em> :</span></p></td>
465
425
<td>a pointer to the block to free
470
<p class="since">Since 2.10
430
<p class="since">Since 2.10</p>
476
433
<div class="refsect2" lang="en">
477
<a name="id3287732"></a><h3>
478
<a name="g-slice-free-chain"></a>g_slice_free_chain()</h3>
479
<a class="indexterm" name="id3287747"></a><pre class="programlisting">#define g_slice_free_chain(type, mem_chain, next)</pre>
434
<a name="g-slice-free-chain"></a><h3>g_slice_free_chain()</h3>
435
<pre class="programlisting">#define g_slice_free_chain(type, mem_chain, next)</pre>
481
437
Frees a linked list of memory blocks of structure type <em class="parameter"><code>type</code></em>.
482
438
The memory blocks must be equal-sized, allocated via
483
<a class="link" href="glib-Memory-Slices.html#g-slice-alloc"><code class="function">g_slice_alloc()</code></a> or <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0"><code class="function">g_slice_alloc0()</code></a> and linked together by a
484
<em class="parameter"><code>next</code></em> pointer (similar to <a class="link" href="glib-Singly-Linked-Lists.html#GSList"><span class="type">GSList</span></a>). The name of the
439
<a class="link" href="glib-Memory-Slices.html#g-slice-alloc" title="g_slice_alloc ()"><code class="function">g_slice_alloc()</code></a> or <a class="link" href="glib-Memory-Slices.html#g-slice-alloc0" title="g_slice_alloc0 ()"><code class="function">g_slice_alloc0()</code></a> and linked together by a
440
<em class="parameter"><code>next</code></em> pointer (similar to <a class="link" href="glib-Singly-Linked-Lists.html#GSList" title="GSList"><span class="type">GSList</span></a>). The name of the
485
441
<em class="parameter"><code>next</code></em> field in <em class="parameter"><code>type</code></em> is passed as third argument.
486
442
Note that the exact release behaviour can be changed with the
487
443
<a class="link" href="glib-running.html#G_DEBUG" title="G_DEBUG">G_DEBUG=gc-friendly</a> environment variable,
491
447
<col align="left" valign="top">
494
<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
450
<td><p><span class="term"><em class="parameter"><code>type</code></em> :</span></p></td>
495
451
<td> the type of the <em class="parameter"><code>mem_chain</code></em> blocks
499
<td><p><span class="term"><em class="parameter"><code>mem_chain</code></em> :</span></p></td>
455
<td><p><span class="term"><em class="parameter"><code>mem_chain</code></em> :</span></p></td>
500
456
<td> a pointer to the first block of the chain
504
<td><p><span class="term"><em class="parameter"><code>next</code></em> :</span></p></td>
460
<td><p><span class="term"><em class="parameter"><code>next</code></em> :</span></p></td>
505
461
<td> the field name of the next pointer in <em class="parameter"><code>type</code></em>
510
<p class="since">Since 2.10
516
<div class="refsect1" lang="en">
517
<a name="id3287902"></a><div class="refsect2" lang="en"><a name="id3287903"></a></div>
519
<div class="refsect2" lang="en"><a name="id3287904"></a></div>
466
<p class="since">Since 2.10</p>
521
469
<div class="footnotes">
522
470
<br><hr width="100" align="left">
523
<div class="footnote"><p><sup>[<a name="ftn.id3286464" href="#id3286464" class="para">6</a>] </sup>
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<div class="footnote"><p><sup>[<a name="ftn.id3337918" href="#id3337918" class="para">6</a>] </sup>
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<a class="ulink" href="http://citeseer.ist.psu.edu/bonwick94slab.html" target="_top">[Bonwick94]</a> Jeff Bonwick, The slab allocator: An object-caching kernel
525
memory allocator. USENIX 1994, and
473
memory allocator. USENIX 1994, and
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<a class="ulink" href="http://citeseer.ist.psu.edu/bonwick01magazines.html" target="_top">[Bonwick01]</a> Bonwick and Jonathan Adams, Magazines and vmem: Extending the
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slab allocator to many cpu's and arbitrary resources. USENIX 2001
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