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+<html>
+ <head>
+ <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+ <meta http-equiv="Content-Language" content="en" />
+ <title>skalibs: the alloc library interface</title>
+ <meta name="Description" content="skalibs: the alloc library interface" />
+ <meta name="Keywords" content="skalibs c unix alloc library libstddjb" />
+ <!-- <link rel="stylesheet" type="text/css" href="http://skarnet.org/default.css" /> -->
+ </head>
+<body>
+
+<p>
+<a href="index.html">libstddjb</a><br />
+<a href="../libskarnet.html">libskarnet</a><br />
+<a href="../index.html">skalibs</a><br />
+<a href="http://skarnet.org/software/">Software</a><br />
+<a href="http://skarnet.org/">skarnet.org</a>
+</p>
+
+<h1> The <tt>alloc</tt> library interface </h1>
+
+<p>
+ The following functions are declared in the <tt>skalibs/alloc.h</tt> header,
+and implemented in the <tt>libskarnet.a</tt> or <tt>libskarnet.so</tt> library.
+</p>
+
+<h2> General information </h2>
+
+<p>
+ <tt>alloc</tt> is the skalibs heap memory manager. It's actually a
+wrapper for the
+<a href="http://www.opengroup.org/onlinepubs/9699919799/functions/malloc.html">malloc()</a>
+series of functions; it unifies a few system-dependent <tt>malloc</tt>
+behaviours. It's also the API to implement and preload if for some
+reason you need to plug in your own allocator: replacing <tt>alloc()</tt>
+is much easier than replacing <tt>malloc()</tt> safely.
+</p>
+
+<p>
+<strong> As a general rule, you should not be using the <tt>alloc</tt>
+interface directly. </strong> Allocating and freeing individual cells
+in the heap is a recipe for heap fragmentation, as well as cell
+tracking nightmares leading to memory leaks. <strong> You should use
+the higher-level <a href="stralloc.html">stralloc</a> and
+<a href="genalloc.html">genalloc</a> interfaces </strong> to handle dynamic
+arrays of objects.
+</p>
+
+<p>
+ C's lack of automatic management of heap memory is not a drawback: it's
+a feature of the language. It allows for code that is one or two orders
+of magnitude faster than the equivalent in a higher-level language,
+and very low on resources consumption. However, it requires more attention
+from the programmer. Good APIs can significantly reduce the difficulty of
+keeping track of every heap-allocated cell, and every smart programmer
+should favor them over basic interfaces like <tt>malloc()</tt>.
+</p>
+
+<p>
+ <tt>alloc</tt> is used internally by skalibs to implement
+<a href="stralloc.html">stralloc</a>, and nowhere else.
+</p>
+
+<h2> Functions </h2>
+
+<p>
+<code> char *alloc (unsigned int len) </code> <br />
+Allocates a block of <em>len</em> bytes in the heap and returns a pointer
+to the start of the block (or NULL if it failed). Though the pointer type
+is <tt>char *</tt>, the block of memory is correctly aligned for any type
+of object. If <em>len</em> is 0, the function returns a pointer that
+cannot be written to, but that is <em>not null</em>. Note that this is
+different from the required C99 behaviour for <tt>malloc()</tt>.
+</p>
+
+<p>
+<code> void alloc_free (void *p) </code> <br />
+Frees the block of heap memory pointed to by <em>p</em>.
+</p>
+
+<p>
+<code> int alloc_realloc (char **p, unsigned int newlen) </code> <br />
+Redimension the block of heap memory pointed to by *<em>p</em> to
+<em>newlen</em> bytes. The block may have to be moved, in which case
+*<em>p</em> will be modified. Normally returns 1; if an error occurred,
+returns 0 and sets errno, and neither *<em>p</em> nor its contents are
+modified.
+</p>
+
+<p>
+<code> int alloc_re (char **p, unsigned int oldlen, unsigned int newlen) </code> <br />
+Legacy interface for reallocation. It works like <tt>alloc_realloc</tt>,
+except that the original block length must be provided as the <em>oldlen</em>
+argument.
+</p>
+
+</body>
+</html>