11.6. Quick Reference

11.6. Quick Reference

The following symbols were introduced in this chapter:

#include
typedef u8;
typedef u16;
typedef u32;
typedef u64;

Types guaranteed to be 8-, 16-, 32-, and 64-bit unsigned integer values. The equivalent signed types exist as well. In user space, you can refer to the types as _ _u8, _ _u16, and so forth.

#include
PAGE_SIZE
PAGE_SHIFT

Symbols that define the number of bytes per page for the current architecture and the number of bits in the page offset (12 for 4-KB pages and 13 for 8-KB pages).

#include
_ _LITTLE_ENDIAN
_ _BIG_ENDIAN

Only one of the two symbols is defined, depending on the architecture.

#include
u32 _ _cpu_to_le32 (u32);
u32 _ _le32_to_cpu (u32);

Functions that convert between known byte orders and that of the processor. There are more than 60 such functions; see the various files in include/linux/byteorder/ for a full list and the ways in which they are defined.

#include
get_unaligned(ptr);
put_unaligned(val, ptr);

Some architectures need to protect unaligned data access using these macros. The macros expand to normal pointer dereferencing for architectures that permit you to access unaligned data.

#include
void *ERR_PTR(long error);
long PTR_ERR(const void *ptr);
long IS_ERR(const void *ptr);

Functions allow error codes to be returned by functions that return a pointer value.

#include
list_add(struct list_head *new, struct list_head *head);
list_add_tail(struct list_head *new, struct list_head *head);
list_del(struct list_head *entry);
list_del_init(struct list_head *entry);
list_empty(struct list_head *head);
list_entry(entry, type, member);
list_move(struct list_head *entry, struct list_head *head);
list_move_tail(struct list_head *entry, struct list_head *head);
list_splice(struct list_head *list, struct list_head *head);
Functions that manipulate circular, doubly linked lists.
list_for_each(struct list_head *cursor, struct list_head *list)
list_for_each_prev(struct list_head *cursor, struct list_head *list)
list_for_each_safe(struct list_head *cursor, struct list_head *next, struct
list_head *list)
list_for_each_entry(type *cursor, struct list_head *list, member)
list_for_each_entry_safe(type *cursor, type *next struct list_head *list,
member)
Convenience macros for iterating through linked lists.