Types — Generic data types used in the cairo API


typedef             cairo_bool_t;
void                (*cairo_destroy_func_t)             (void *data);




typedef int cairo_bool_t;

cairo_bool_t is used for boolean values. Returns of type cairo_bool_t will always be either 0 or 1, but testing against these values explicitly is not encouraged; just use the value as a boolean condition.

 if (cairo_in_stroke (cr, x, y)) {
     /* do something */


typedef struct {
    int unused;
} cairo_user_data_key_t;

cairo_user_data_key_t is used for attaching user data to cairo data structures. The actual contents of the struct is never used, and there is no need to initialize the object; only the unique address of a cairo_data_key_t object is used. Typically, you would just use the address of a static cairo_data_key_t object.

int unused; not used; ignore.

cairo_destroy_func_t ()

void                (*cairo_destroy_func_t)             (void *data);

cairo_destroy_func_t the type of function which is called when a data element is destroyed. It is passed the pointer to the data element and should free any memory and resources allocated for it.

data : The data element being destroyed.