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<title>uthash: a hash table for C structures</title>
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<a href="http://github.com/troydhanson/uthash">GitHub page</a> >
uthash home <!-- http://troydhanson.github.com/uthash/ -->
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<h2>documentation</h2>
<div><a href="userguide.html">uthash</a></div>
<div><a href="utlist.html">utlist</a></div>
<div><a href="utarray.html">utarray</a></div>
<div><a href="utringbuffer.html">utringbuffer</a></div>
<div><a href="utstack.html">utstack</a></div>
<div><a href="utstring.html">utstring</a></div>
<h2>download</h2>
<h3>GNU/Linux, Windows</h3>
<div><a href=https://github.com/troydhanson/uthash/archive/master.zip>uthash-master.zip</a></div>
<div><a href=https://github.com/troydhanson/uthash>git clone</a></div>
<h2>license</h2>
<div><a href="license.html">BSD revised</a></div>
<h2>developer</h2>
<div><a href="http://troydhanson.github.io/">Troy D. Hanson</a></div>
<h2>maintainer</h2>
<div><a href="https://github.com/Quuxplusone">Arthur O'Dwyer</a></div>
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Any C structure can be stored in a hash table using uthash. Just add a
<em>UT_hash_handle</em> to the structure and choose one or more fields
in your structure to act as the key. Then use these macros to store,
retrieve or delete items from the hash table.
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Example 1. Adding an item to a hash.
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<pre>
#include "uthash.h"
struct my_struct {
int id; /* we'll use this field as the key */
char name[10];
UT_hash_handle hh; /* makes this structure hashable */
};
struct my_struct *users = NULL;
void add_user(struct my_struct *s) {
HASH_ADD_INT( users, id, s );
}
</pre>
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Example 2. Looking up an item in a hash.
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<pre>
struct my_struct *find_user(int user_id) {
struct my_struct *s;
HASH_FIND_INT( users, &user_id, s );
return s;
}
</pre>
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Example 3. Deleting an item from a hash.
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<pre>
void delete_user(struct my_struct *user) {
HASH_DEL( users, user);
}
</pre>
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For more information and examples, please see the <a href="userguide.html">User Guide.</a>
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