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<!--replace-end-7--><!--replace-end-4--><!--replace-end-1--></head><body><div class="ui fluid container universe"><!--replace-start-2--><!--replace-start-3--><!--replace-start-6--><div class="ui text container" id="zettel-container" style="position: relative"><div class="zettel-view"><article class="ui raised attached segment zettel-content"><div class="pandoc"><h1 id="title-h1">Heap memory</h1><p>Along with <span class="zettel-link-container cf"><span class="zettel-link" title="Zettel: Stack memory"><a href="Stack_memory.html">Stack memory</a></span></span>, programs make use of <em>heap memory</em> during runtime.</p><p>Heap memory does not use a standardised data structure and can be accessed from any point within the program.</p><p>Whereas stack memory with it’s LIFO structure has memory management built-in when programs allocate memory from the heap they must manually deallocate it when it is no longer required. This process of “freeing memory” is known as <em>garbage collection</em>. In a language like C, this is the explicit concern of the programmer and is not abstracted away. Failure to properly manage garbage collection is what causes <span class="zettel-link-container cf"><span class="zettel-link"><a href="Memory_leaks.html">Memory leaks</a></span></span>.</p><p>Heap memory is used in combination with the stack since a given heap memory allocation address is stored as a stack variable during runtime. It points to the heap memory address whilst not being that memory itself.</p><p>Here is an example of managing heap memory allocation in C:</p><pre><code class="c language-c">void * data;
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data = malloc(512)</code></pre><p>The first line assigns a special <em>pointer</em> variable (indicated by <code>void *</code> rather than <code>int</code> or <code>str</code>) . This is a variable only holds a memory address. The <code>malloc</code> method requests 512 bytes that it wants to assign to the <code>data</code> variable. It will return the address of the first byte in the newly allocated memory. <code>data</code> will then refer to the address on the stack that holds the address allocation on the heap.</p><h2 id="related-notes">Related notes</h2></div></article><nav class="ui attached segment deemphasized backlinksPane" id="neuron-backlinks-pane"><h3 class="ui header">Backlinks</h3><ul class="backlinks"><li><span class="zettel-link-container cf"><span class="zettel-link"><a href="Stack_memory.html">Stack memory</a></span></span><ul class="context-list" style="zoom: 85%;"><li class="item"><div class="pandoc"><p>Along with <span class="zettel-link-container cf"><span class="zettel-link" title="Zettel: Heap memory"><a href="Heap_memory.html">heap memory</a></span></span> heap memory, programs make use of <em>stack memory</em> during runtime.</p></div></li></ul></li></ul></nav><nav class="ui attached segment deemphasized bottomPane" id="neuron-tags-pane"><div><span class="ui basic label zettel-tag" title="Tag">C</span><span class="ui basic label zettel-tag" title="Tag">memory</span></div></nav><nav class="ui bottom attached icon compact inverted menu blue" id="neuron-nav-bar"><!--replace-start-9--><!--replace-end-9--><a class="right item" href="impulse.html" title="Open Impulse"><i class="wave square icon"></i></a></nav></div></div><!--replace-end-6--><!--replace-end-3--><!--replace-end-2--><div class="ui center aligned container footer-version"><div class="ui tiny image"><a href="https://neuron.zettel.page"><img alt="logo" src="https://raw.githubusercontent.com/srid/neuron/master/assets/neuron.svg" title="Generated by Neuron 1.9.35.3" /></a></div></div></div></body></html> |