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Pointer ArraysPointer Arrays — arrays of pointers to any type of data, which grow automatically as new elements are added |
Functions
GPtrArray * | g_ptr_array_new () |
GPtrArray * | g_ptr_array_sized_new () |
GPtrArray * | g_ptr_array_new_with_free_func () |
GPtrArray * | g_ptr_array_new_full () |
void | g_ptr_array_set_free_func () |
GPtrArray * | g_ptr_array_ref () |
void | g_ptr_array_unref () |
void | g_ptr_array_add () |
void | g_ptr_array_insert () |
gboolean | g_ptr_array_remove () |
gpointer | g_ptr_array_remove_index () |
gboolean | g_ptr_array_remove_fast () |
gpointer | g_ptr_array_remove_index_fast () |
GPtrArray * | g_ptr_array_remove_range () |
void | g_ptr_array_sort () |
void | g_ptr_array_sort_with_data () |
void | g_ptr_array_set_size () |
#define | g_ptr_array_index() |
gpointer * | g_ptr_array_free () |
void | g_ptr_array_foreach () |
gboolean | g_ptr_array_find () |
gboolean | g_ptr_array_find_with_equal_func () |
Description
Pointer Arrays are similar to Arrays but are used only for storing pointers.
If you remove elements from the array, elements at the end of the array are moved into the space previously occupied by the removed element. This means that you should not rely on the index of particular elements remaining the same. You should also be careful when deleting elements while iterating over the array.
To create a pointer array, use g_ptr_array_new()
.
To add elements to a pointer array, use g_ptr_array_add()
.
To remove elements from a pointer array, use g_ptr_array_remove()
,
g_ptr_array_remove_index()
or g_ptr_array_remove_index_fast()
.
To access an element of a pointer array, use g_ptr_array_index()
.
To set the size of a pointer array, use g_ptr_array_set_size()
.
To free a pointer array, use g_ptr_array_free()
.
An example using a GPtrArray:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
GPtrArray *array; gchar *string1 = "one"; gchar *string2 = "two"; gchar *string3 = "three"; array = g_ptr_array_new (); g_ptr_array_add (array, (gpointer) string1); g_ptr_array_add (array, (gpointer) string2); g_ptr_array_add (array, (gpointer) string3); if (g_ptr_array_index (array, 0) != (gpointer) string1) g_print ("ERROR: got %p instead of %p\n", g_ptr_array_index (array, 0), string1); g_ptr_array_free (array, TRUE); |
Functions
g_ptr_array_new ()
GPtrArray *
g_ptr_array_new (void
);
Creates a new GPtrArray with a reference count of 1.
g_ptr_array_sized_new ()
GPtrArray *
g_ptr_array_sized_new (guint reserved_size
);
Creates a new GPtrArray with reserved_size
pointers preallocated
and a reference count of 1. This avoids frequent reallocation, if
you are going to add many pointers to the array. Note however that
the size of the array is still 0.
g_ptr_array_new_with_free_func ()
GPtrArray *
g_ptr_array_new_with_free_func (GDestroyNotify element_free_func
);
Creates a new GPtrArray with a reference count of 1 and use
element_free_func
for freeing each element when the array is destroyed
either via g_ptr_array_unref()
, when g_ptr_array_free()
is called with
free_segment
set to TRUE
or when removing elements.
Since: 2.22
g_ptr_array_new_full ()
GPtrArray * g_ptr_array_new_full (guint reserved_size
,GDestroyNotify element_free_func
);
Creates a new GPtrArray with reserved_size
pointers preallocated
and a reference count of 1. This avoids frequent reallocation, if
you are going to add many pointers to the array. Note however that
the size of the array is still 0. It also set element_free_func
for freeing each element when the array is destroyed either via
g_ptr_array_unref()
, when g_ptr_array_free()
is called with
free_segment
set to TRUE
or when removing elements.
Parameters
reserved_size |
number of pointers preallocated |
|
element_free_func |
A function to free elements with
destroy |
[nullable] |
Since: 2.30
g_ptr_array_set_free_func ()
void g_ptr_array_set_free_func (GPtrArray *array
,GDestroyNotify element_free_func
);
Sets a function for freeing each element when array
is destroyed
either via g_ptr_array_unref()
, when g_ptr_array_free()
is called
with free_segment
set to TRUE
or when removing elements.
Since: 2.22
g_ptr_array_ref ()
GPtrArray *
g_ptr_array_ref (GPtrArray *array
);
Atomically increments the reference count of array
by one.
This function is thread-safe and may be called from any thread.
Since: 2.22
g_ptr_array_unref ()
void
g_ptr_array_unref (GPtrArray *array
);
Atomically decrements the reference count of array
by one. If the
reference count drops to 0, the effect is the same as calling
g_ptr_array_free()
with free_segment
set to TRUE
. This function
is thread-safe and may be called from any thread.
Since: 2.22
g_ptr_array_add ()
void g_ptr_array_add (GPtrArray *array
,gpointer data
);
Adds a pointer to the end of the pointer array. The array will grow in size automatically if necessary.
g_ptr_array_insert ()
void g_ptr_array_insert (GPtrArray *array
,gint index_
,gpointer data
);
Inserts an element into the pointer array at the given index. The array will grow in size automatically if necessary.
Parameters
array |
||
index_ |
the index to place the new element at, or -1 to append |
|
data |
the pointer to add. |
Since: 2.40
g_ptr_array_remove ()
gboolean g_ptr_array_remove (GPtrArray *array
,gpointer data
);
Removes the first occurrence of the given pointer from the pointer
array. The following elements are moved down one place. If array
has a non-NULL
GDestroyNotify function it is called for the
removed element.
It returns TRUE
if the pointer was removed, or FALSE
if the
pointer was not found.
g_ptr_array_remove_index ()
gpointer g_ptr_array_remove_index (GPtrArray *array
,guint index_
);
Removes the pointer at the given index from the pointer array.
The following elements are moved down one place. If array
has
a non-NULL
GDestroyNotify function it is called for the removed
element.
g_ptr_array_remove_fast ()
gboolean g_ptr_array_remove_fast (GPtrArray *array
,gpointer data
);
Removes the first occurrence of the given pointer from the pointer
array. The last element in the array is used to fill in the space,
so this function does not preserve the order of the array. But it
is faster than g_ptr_array_remove()
. If array
has a non-NULL
GDestroyNotify function it is called for the removed element.
It returns TRUE
if the pointer was removed, or FALSE
if the
pointer was not found.
g_ptr_array_remove_index_fast ()
gpointer g_ptr_array_remove_index_fast (GPtrArray *array
,guint index_
);
Removes the pointer at the given index from the pointer array.
The last element in the array is used to fill in the space, so
this function does not preserve the order of the array. But it
is faster than g_ptr_array_remove_index()
. If array
has a non-NULL
GDestroyNotify function it is called for the removed element.
g_ptr_array_remove_range ()
GPtrArray * g_ptr_array_remove_range (GPtrArray *array
,guint index_
,guint length
);
Removes the given number of pointers starting at the given index
from a GPtrArray. The following elements are moved to close the
gap. If array
has a non-NULL
GDestroyNotify function it is
called for the removed elements.
Parameters
array |
a |
|
index_ |
the index of the first pointer to remove |
|
length |
the number of pointers to remove |
Since: 2.4
g_ptr_array_sort ()
void g_ptr_array_sort (GPtrArray *array
,GCompareFunc compare_func
);
Sorts the array, using compare_func
which should be a qsort()
-style
comparison function (returns less than zero for first arg is less
than second arg, zero for equal, greater than zero if irst arg is
greater than second arg).
Note that the comparison function for g_ptr_array_sort()
doesn't
take the pointers from the array as arguments, it takes pointers to
the pointers in the array.
This is guaranteed to be a stable sort since version 2.32.
g_ptr_array_sort_with_data ()
void g_ptr_array_sort_with_data (GPtrArray *array
,GCompareDataFunc compare_func
,gpointer user_data
);
Like g_ptr_array_sort()
, but the comparison function has an extra
user data argument.
Note that the comparison function for g_ptr_array_sort_with_data()
doesn't take the pointers from the array as arguments, it takes
pointers to the pointers in the array.
This is guaranteed to be a stable sort since version 2.32.
g_ptr_array_set_size ()
void g_ptr_array_set_size (GPtrArray *array
,gint length
);
Sets the size of the array. When making the array larger,
newly-added elements will be set to NULL
. When making it smaller,
if array
has a non-NULL
GDestroyNotify function then it will be
called for the removed elements.
g_ptr_array_index()
#define g_ptr_array_index(array,index_)
Returns the pointer at the given index of the pointer array.
This does not perform bounds checking on the given index_
,
so you are responsible for checking it against the array length.
g_ptr_array_free ()
gpointer * g_ptr_array_free (GPtrArray *array
,gboolean free_seg
);
Frees the memory allocated for the GPtrArray. If free_seg
is TRUE
it frees the memory block holding the elements as well. Pass FALSE
if you want to free the GPtrArray wrapper but preserve the
underlying array for use elsewhere. If the reference count of array
is greater than one, the GPtrArray wrapper is preserved but the
size of array
will be set to zero.
If array contents point to dynamically-allocated memory, they should
be freed separately if free_seg
is TRUE
and no GDestroyNotify
function has been set for array
.
This function is not thread-safe. If using a GPtrArray from multiple
threads, use only the atomic g_ptr_array_ref()
and g_ptr_array_unref()
functions.
g_ptr_array_foreach ()
void g_ptr_array_foreach (GPtrArray *array
,GFunc func
,gpointer user_data
);
Calls a function for each element of a GPtrArray. func
must not
add elements to or remove elements from the array.
Parameters
array |
||
func |
the function to call for each array element |
|
user_data |
user data to pass to the function |
Since: 2.4
g_ptr_array_find ()
gboolean g_ptr_array_find (GPtrArray *haystack
,gconstpointer needle
,guint *index_
);
Checks whether needle
exists in haystack
. If the element is found, TRUE
is
returned and the element’s index is returned in index_
(if non-NULL
).
Otherwise, FALSE
is returned and index_
is undefined. If needle
exists
multiple times in haystack
, the index of the first instance is returned.
This does pointer comparisons only. If you want to use more complex equality
checks, such as string comparisons, use g_ptr_array_find_with_equal_func()
.
[skip]
Parameters
haystack |
pointer array to be searched |
|
needle |
pointer to look for |
|
index_ |
return location for the index of the element, if found. |
[optional][out caller-allocates] |
Since: 2.54
g_ptr_array_find_with_equal_func ()
gboolean g_ptr_array_find_with_equal_func (GPtrArray *haystack
,gconstpointer needle
,GEqualFunc equal_func
,guint *index_
);
Checks whether needle
exists in haystack
, using the given equal_func
.
If the element is found, TRUE
is returned and the element’s index is
returned in index_
(if non-NULL
). Otherwise, FALSE
is returned and index_
is undefined. If needle
exists multiple times in haystack
, the index of
the first instance is returned.
equal_func
is called with the element from the array as its first parameter,
and needle
as its second parameter. If equal_func
is NULL
, pointer
equality is used.
[skip]
Parameters
haystack |
pointer array to be searched |
|
needle |
pointer to look for |
|
equal_func |
the function to call for each element, which should
return |
[nullable] |
index_ |
return location for the index of the element, if found. |
[optional][out caller-allocates] |
Since: 2.54