Sets our main struct and passes it to the parent class
Creates a new GHashTable with a reference count of 1. Hash values returned by hash_func are used to determine where keys are stored within the GHashTable data structure. The g_direct_hash(), g_int_hash(), g_int64_hash(), g_double_hash() and g_str_hash() functions are provided for some common types of keys. If hash_func is NULL, g_direct_hash() is used. key_equal_func is used when looking up keys in the GHashTable. The g_direct_equal(), g_int_equal(), g_int64_equal(), g_double_equal() and g_str_equal() functions are provided for the most common types of keys. If key_equal_func is NULL, keys are compared directly in a similar fashion to g_direct_equal(), but without the overhead of a function call.
Creates a new GHashTable like g_hash_table_new() with a reference count of 1 and allows to specify functions to free the memory allocated for the key and value that get called when removing the entry from the GHashTable.
This is a convenience function for using a GHashTable as a set. It is equivalent to calling g_hash_table_replace() with key as both the key and the value. When a hash table only ever contains keys that have themselves as the corresponding value it is able to be stored more efficiently. See the discussion in the section description. Since 2.32
Checks if key is in hash_table. Since 2.32
Destroys all keys and values in the GHashTable and decrements its reference count by 1. If keys and/or values are dynamically allocated, you should either free them first or create the GHashTable with destroy notifiers using g_hash_table_new_full(). In the latter case the destroy functions you supplied will be called on all keys and values during the destruction phase.
Atomically increments the reference count of hash_table by one. This function is MT-safe and may be called from any thread. Since 2.10
Calls the given function for key/value pairs in the GHashTable until predicate returns TRUE. The function is passed the key and value of each pair, and the given user_data parameter. The hash table may not be modified while iterating over it (you can't add/remove items). Note, that hash tables are really only optimized for forward lookups, i.e. g_hash_table_lookup(). So code that frequently issues g_hash_table_find() or g_hash_table_foreach() (e.g. in the order of once per every entry in a hash table) should probably be reworked to use additional or different data structures for reverse lookups (keep in mind that an O(n) find/foreach operation issued for all n values in a hash table ends up needing O(n*n) operations). Since 2.4
Calls the given function for each of the key/value pairs in the GHashTable. The function is passed the key and value of each pair, and the given user_data parameter. The hash table may not be modified while iterating over it (you can't add/remove items). To remove all items matching a predicate, use g_hash_table_foreach_remove(). See g_hash_table_find() for performance caveats for linear order searches in contrast to g_hash_table_lookup().
Calls the given function for each key/value pair in the GHashTable. If the function returns TRUE, then the key/value pair is removed from the GHashTable. If you supplied key or value destroy functions when creating the GHashTable, they are used to free the memory allocated for the removed keys and values. See GHashTableIter for an alternative way to loop over the key/value pairs in the hash table.
Calls the given function for each key/value pair in the GHashTable. If the function returns TRUE, then the key/value pair is removed from the GHashTable, but no key or value destroy functions are called. See GHashTableIter for an alternative way to loop over the key/value pairs in the hash table.
Retrieves every key inside hash_table. The returned data is valid until changes to the hash release those keys. Since 2.14
the main Gtk struct as a void*
Retrieves every value inside hash_table. The returned data is valid until hash_table is modified. Since 2.14
Inserts a new key and value into a GHashTable. If the key already exists in the GHashTable its current value is replaced with the new value. If you supplied a value_destroy_func when creating the GHashTable, the old value is freed using that function. If you supplied a key_destroy_func when creating the GHashTable, the passed key is freed using that function.
Looks up a key in a GHashTable. Note that this function cannot distinguish between a key that is not present and one which is present and has the value NULL. If you need this distinction, use g_hash_table_lookup_extended().
Looks up a key in the GHashTable, returning the original key and the associated value and a gboolean which is TRUE if the key was found. This is useful if you need to free the memory allocated for the original key, for example before calling g_hash_table_remove(). You can actually pass NULL for lookup_key to test whether the NULL key exists, provided the hash and equal functions of hash_table are NULL-safe.
Removes a key and its associated value from a GHashTable. If the GHashTable was created using g_hash_table_new_full(), the key and value are freed using the supplied destroy functions, otherwise you have to make sure that any dynamically allocated values are freed yourself.
Removes all keys and their associated values from a GHashTable. If the GHashTable was created using g_hash_table_new_full(), the keys and values are freed using the supplied destroy functions, otherwise you have to make sure that any dynamically allocated values are freed yourself. Since 2.12
Inserts a new key and value into a GHashTable similar to g_hash_table_insert(). The difference is that if the key already exists in the GHashTable, it gets replaced by the new key. If you supplied a value_destroy_func when creating the GHashTable, the old value is freed using that function. If you supplied a key_destroy_func when creating the GHashTable, the old key is freed using that function.
Returns the number of elements contained in the GHashTable.
Removes a key and its associated value from a GHashTable without calling the key and value destroy functions.
Removes all keys and their associated values from a GHashTable without calling the key and value destroy functions. Since 2.12
Atomically decrements the reference count of hash_table by one. If the reference count drops to 0, all keys and values will be destroyed, and all memory allocated by the hash table is released. This function is MT-safe and may be called from any thread. Since 2.10
Compares two gpointer arguments and returns TRUE if they are equal. It can be passed to g_hash_table_new() as the key_equal_func parameter, when using opaque pointers compared by pointer value as keys in a GHashTable. This equality function is also appropriate for keys that are integers stored in pointers, such as GINT_TO_POINTER (n).
Converts a gpointer to a hash value. It can be passed to g_hash_table_new() as the hash_func parameter, when using opaque pointers compared by pointer value as keys in a GHashTable. This hash function is also appropriate for keys that are integers stored in pointers, such as GINT_TO_POINTER (n).
Compares the two gdouble values being pointed to and returns TRUE if they are equal. It can be passed to g_hash_table_new() as the key_equal_func parameter, when using non-NULL pointers to doubles as keys in a GHashTable. Since 2.22
Converts a pointer to a gdouble to a hash value. It can be passed to g_hash_table_new() as the hash_func parameter, It can be passed to g_hash_table_new() as the hash_func parameter, when using non-NULL pointers to doubles as keys in a GHashTable. Since 2.22
Compares the two gint64 values being pointed to and returns TRUE if they are equal. It can be passed to g_hash_table_new() as the key_equal_func parameter, when using non-NULL pointers to 64-bit integers as keys in a GHashTable. Since 2.22
Converts a pointer to a gint64 to a hash value. It can be passed to g_hash_table_new() as the hash_func parameter, when using non-NULL pointers to 64-bit integer values as keys in a GHashTable. Since 2.22
Compares the two gint values being pointed to and returns TRUE if they are equal. It can be passed to g_hash_table_new() as the key_equal_func parameter, when using non-NULL pointers to integers as keys in a GHashTable.
Converts a pointer to a gint to a hash value. It can be passed to g_hash_table_new() as the hash_func parameter, when using non-NULL pointers to integer values as keys in a GHashTable.
Compares two strings for byte-by-byte equality and returns TRUE if they are equal. It can be passed to g_hash_table_new() as the key_equal_func parameter, when using non-NULL strings as keys in a GHashTable. Note that this function is primarily meant as a hash table comparison function. For a general-purpose, NULL-safe string comparison function, see g_strcmp0().
Converts a string to a hash value. This function implements the widely used "djb" hash apparently posted by Daniel Bernstein to comp.lang.c some time ago. The 32 bit unsigned hash value starts at 5381 and for each byte 'c' in the string, is updated: hash = hash * 33 + c. This function uses the signed value of each byte. It can be passed to g_hash_table_new() as the hash_func parameter, when using non-NULL strings as keys in a GHashTable.
the main Gtk struct
A GHashTable provides associations between keys and values which is optimized so that given a key, the associated value can be found very quickly.
Note that neither keys nor values are copied when inserted into the GHashTable, so they must exist for the lifetime of the GHashTable. This means that the use of static strings is OK, but temporary strings (i.e. those created in buffers and those returned by GTK+ widgets) should be copied with g_strdup() before being inserted.
If keys or values are dynamically allocated, you must be careful to ensure that they are freed when they are removed from the GHashTable, and also when they are overwritten by new insertions into the GHashTable. It is also not advisable to mix static strings and dynamically-allocated strings in a GHashTable, because it then becomes difficult to determine whether the string should be freed.
To create a GHashTable, use g_hash_table_new().
To insert a key and value into a GHashTable, use g_hash_table_insert().
To lookup a value corresponding to a given key, use g_hash_table_lookup() and g_hash_table_lookup_extended().
g_hash_table_lookup_extended() can also be used to simply check if a key is present in the hash table.
To remove a key and value, use g_hash_table_remove().
To call a function for each key and value pair use g_hash_table_foreach() or use a iterator to iterate over the key/value pairs in the hash table, see GHashTableIter.
To destroy a GHashTable use g_hash_table_destroy().
A common use-case for hash tables is to store information about a set of keys, without associating any particular value with each key. GHashTable optimizes one way of doing so: If you store only key-value pairs where key == value, then GHashTable does not allocate memory to store the values, which can be a considerable space saving, if your set is large. The functions g_hash_table_add() and g_hash_table_contains() are designed to be used when using GHashTable this way.