Binary and ternary functions: GXLib Reference Manual

Binary and ternary functions

Binary and ternary functions — common functions that map 2 or 3 parameters to some value.

Functions

gpointer	(*GXBinaryFunc) ()
gconstpointer	gx_identity ()
gpointer	(*GXTernaryFunc) ()
gint	gx_plus ()
gint	gx_times ()
gint	gx_max ()
gint	gx_min ()

Description

These functions are designed as simple adapters for use with functions such as gx_list_fold() .

For example, let's calculate the product of 5, 10, 15, 20, 25.

GList *lst;
int    sum;

lst = gx_list_iota (5, 5, 5); // 5, 10, 15, 20, 25
sum = GPOINTER_TO_INT(gx_list_fold (lst, (GXTernaryFunc)gx_times,
                                    GINT_TO_POINTER(1), NULL, NULL));
g_assert_cmpint (sum,==, 375000);
g_list_free (lst);

Obviously, for such a simple case, the gx_list_fold() solution looks a bit convoluted compared to an explicit loop.

Functions

GXBinaryFunc ()

gpointer
(*GXBinaryFunc) (gconstpointer ptr,
                 gconstpointer user_data);

Prototype for a binary function to be used in e.g. gx_list_map(), that takes some data-pointer and and an optional user-provided pointer, and returns a pointer as result.

Parameters

ptr	a pointer
user_data	a user-provided data pointer.	[allow-none]

Returns

some pointer value for the result.

gx_identity ()

gconstpointer
gx_identity (gconstpointer ptr);

The identity function; maps a value to itself.

1
2
3

const char *str;
str =  "FOO";
g_assert (gx_identity (str) == str);

Parameters

ptr

a pointer

Returns

the pointer ptr .

GXTernaryFunc ()

gpointer
(*GXTernaryFunc) (gconstpointer p1,
                  gconstpointer p2,
                  gconstpointer user_data);

Prototype for a ternary function to be used in e.g. gx_list_fold(), that takes two data-pointers and an optional user-provided pointer, and returns a pointer as result.

Parameters

p1	first pointer argument
p2	second pointer argument
user_data	a user-provided data pointer.	[allow-none]

Returns

some pointer value for the result.

gx_plus ()

gint
gx_plus (gint i,
         gint j);

Calculates the sum of i and j . This function is useful when composing it with other functions, such as gx_list_fold().

1	g_assert_cmpint (gx_plus (3, 4),==, 3 + 4);

Parameters

i	an integer value
j	another integer value

Returns

i + j

gx_times ()

gint
gx_times (gint i,
          gint j);

Calculates the product of i and j . This function is useful when composing it with other functions, such as gx_list_fold().

1	g_assert_cmpint (gx_times (8, 7),==, 8 * 7);

Parameters

i	an integer value
j	another integer value

Returns

i ✕ j

gx_max ()

gint
gx_max (gint i,
        gint j);

Get the greatest value of i and j . This function is useful when composing it with other functions, such as gx_list_fold().

1	g_assert_cmpint (gx_max (100, 1000),==, MAX(100, 1000));

Parameters

i	an integer value
j	another integer value

Returns

the greatest of i and j .

gx_min ()

gint
gx_min (gint i,
        gint j);

Get the smallest value of i and j . This function is useful when composing it with other functions, such as gx_list_fold().

1	g_assert_cmpint (gx_min (123456, 54321),==, MIN(123456, 54321));

Parameters

i	an integer value
j	another integer value

Returns

the smallest of i and j .