cxx Namespace Reference

Our C++ library. More...

Namespaces
namespace	Bits
	Internal helpers for the cxx package.

Data Structures
class	Avl_map
	AVL tree based associative container. More...
class	Avl_set
	AVL set for simple compareable items. More...
class	Avl_tree
	A generic AVL tree. More...
class	Avl_tree_node
	Node of an AVL tree. More...
class	Base_slab
	Basic slab allocator. More...
class	Base_slab_static
	Merged slab allocator (allocators for objects of the same size are merged together). More...
class	Bitfield
	Definition for a member (part) of a bit field. More...
class	Bitmap
	A static bitmap. More...
class	Bitmap_base
	Basic bitmap abstraction. More...
class	H_list
	General double-linked list of unspecified cxx::H_list_item elements. More...
class	H_list_item_t
	Basic element type for a double-linked H_list. More...
struct	H_list_t
	Double-linked list of typed H_list_item_t elements. More...
class	List
	Doubly linked list, with internal allocation. More...
class	List_alloc
	Standard list-based allocator. More...
class	List_item
	Basic list item. More...
struct	Lt_functor
	Generic comparator class that defaults to the less-than operator. More...
class	New_allocator
	Standard allocator based on operator new () . More...
class	Nothrow
	Helper type to distinguish the oeprator new version that does not throw exceptions. More...
struct	Pair
	Pair of two values. More...
class	Pair_first_compare
	Comparison functor for Pair. More...
struct	Ref_obj_list_item
	Item for list linked via cxx::Ref_ptr with default refence counting. More...
class	Ref_ptr
	A reference-counting pointer with automatic cleanup. More...
class	S_list
	Simple single-linked list. More...
class	Slab
	Slab allocator for object of type Type. More...
class	Slab_static
	Merged slab allocator (allocators for objects of the same size are merged together). More...
class	static_vector
	Simple encapsulation for a dynamically allocated array. More...
class	String
	Allocation free string class with explicit length field. More...
class	Weak_ref
	Typed weak reference to an object of type T. More...
class	Weak_ref_base
	Generic (base) weak reference to some object. More...

Typedefs
typedef H_list_item_t< void >	H_list_item
	Untyped list item.
template<typename T >
using	Ref_ptr_list_item = Bits::Smart_ptr_list_item< T, cxx::Ref_ptr< T > >
	Item for list linked with cxx::Ref_ptr.
template<typename T >
using	Ref_ptr_list = Bits::Smart_ptr_list< Ref_ptr_list_item< T > >
	Single-linked list where elements are connected via a cxx::Ref_ptr.
template<typename T >
using	Unique_ptr_list_item = Bits::Smart_ptr_list_item< T, cxx::unique_ptr< T > >
	Item for list linked with cxx::unique_ptr.
template<typename T >
using	Unique_ptr_list = Bits::Smart_ptr_list< Unique_ptr_list_item< T > >
	Single-linked list where elements are connected with a cxx::unique_ptr.

Functions
template<typename A , typename ... ARGS>
constexpr A const &	min (A const &a1, A const &a2, ARGS const &...a)
	Get the minimum of a1 and a2 upt to aN.
template<typename A , typename ... ARGS>
constexpr A const &	min (cxx::identity_t< A > const &a1, cxx::identity_t< A > const &a2, ARGS const &...a)
	Get the minimum of a1 and a2 upt to aN.
template<typename A , typename ... ARGS>
constexpr A const &	max (A const &a1, A const &a2, ARGS const &...a)
	Get the maximum of a1 and a2 upt to aN.
template<typename A , typename ... ARGS>
constexpr A const &	max (cxx::identity_t< A > const &a1, cxx::identity_t< A > const &a2, ARGS const &...a)
	Get the maximum of a1 and a2 upt to aN.
template<typename T1 >
T1	clamp (T1 v, T1 lo, T1 hi)
	Limit v to the range given by lo and hi.
template<typename T >
T	access_once (T const *a)
	Read the value at an address at most once.
template<typename T , typename VAL >
void	write_now (T *a, VAL &&val)
	Write a value at an address exactly once.

Detailed Description

Our C++ library.

Small Low-Level C++ Library.

Strings.

Various kinds of C++ utilities.

Function Documentation

access_once()

template<typename T >

T cxx::access_once ( T const *  a )

inline

Read the value at an address at most once.

The read might be omitted if the result is not used by any code unless typename contains volatile. If the read operation has side effects and must not be omitted, use different means like L4drivers::Mmio_register_block or similar.

The compiler is disallowed to reuse a previous read at the same address, for example:

val1 = *a;
val2 = access_once(a);  // compiler may not replace this by val2 = val1;

The compiler is also disallowed to repeat the read, for example:

val1 = access_once(a);
val2 = val1;  // compiler may not replace this by val2 = *a;

The above implies that the compiler is also disallowed to move the read out of or into loops.

Note

The read might still be moved relative to other code.

The value might be read from a hardware cache, not from RAM.

Definition at line 39 of file utils.

Referenced by L4virtio::Svr::Request_processor::next(), and L4virtio::Svr::Request_processor::start().

Here is the caller graph for this function:

write_now()

template<typename T , typename VAL >

void cxx::write_now ( T *  a, VAL &&  val  )

inline

Write a value at an address exactly once.

The compiler is disallowed to skip the write, for example:

*a = val;
write_now(a, val);  // compiler may not skip this line

The compiler is also disallowed to repeat the write.

The above implies that the compiler is also disallowed to move the write out of or into loops.

Note

The write might still be moved relative to other code.

The value might be written just to a hardware cache for the moment, not immediately to RAM.

Definition at line 70 of file utils.