Plank AtomicD class

Atomic double. More...

Typedefs
typedef struct PlankAtomicD *	PlankAtomicDRef
	An opaque reference to the Plank AtomicD object (atomic double).
Functions
PlankAtomicDRef	pl_AtomicD_CreateAndInit ()
	Creates and initialises a Plank AtomicD object and return an oqaque reference to it.
PlankAtomicDRef	pl_AtomicD_Create ()
	Create a Plank AtomicF object and return an oqaque reference to it.
static PlankResult	pl_AtomicD_Init (PlankAtomicDRef p)
	Initialise a Plank AtomicD object.
static PlankResult	pl_AtomicD_DeInit (PlankAtomicDRef p)
	Deinitialise a Plank AtomicD object.
PlankResult	pl_AtomicD_Destroy (PlankAtomicDRef p)
	Destroy a Plank AtomicD object.
static PlankD	pl_AtomicD_Get (PlankAtomicDRef p)
	Get the current value.
static PlankD	pl_AtomicD_GetUnchecked (PlankAtomicDRef p)
	Get the current value nonatomically.
PlankULL	pl_AtomicD_GetExtra (PlankAtomicDRef p)
	Not used for this class.
PlankULL	pl_AtomicD_GetExtraUnchecked (PlankAtomicDRef p)
	Not used for this class.
static PlankD	pl_AtomicD_Swap (PlankAtomicDRef p, PlankD newValue)
	Swap the current value with a new value.
static void	pl_AtomicD_SwapOther (PlankAtomicDRef p1, PlankAtomicDRef p2)
	Swap over two values.
static void	pl_AtomicD_Set (PlankAtomicDRef p, PlankD newValue)
	Set the current value to a new value.
static PlankD	pl_AtomicD_Add (PlankAtomicDRef p, PlankD operand)
	Add a value to the current value.
static PlankD	pl_AtomicD_Subtract (PlankAtomicDRef p, PlankD operand)
	Subtract a value from the current value.
static PlankD	pl_AtomicD_Increment (PlankAtomicDRef p)
	Increment the current value by 1.
static PlankD	pl_AtomicD_Decrement (PlankAtomicDRef p)
	Decrement the current value by 1.
static PlankB	pl_AtomicD_CompareAndSwap (PlankAtomicDRef p, PlankD oldValue, PlankD newValue)
	Swap the current value with a new value if a specified old value is still the current value.

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Detailed Description

Atomic double.

This will be a 64-bit float on all Plank-supported platforms.

On PPC on Mac OS these are not a truly lock-free operations, it uses a lock due to the absence of 64-bit atomic operations.

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Typedef Documentation

typedef struct PlankAtomicD* PlankAtomicDRef

An opaque reference to the Plank AtomicD object (atomic double).

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Function Documentation

static PlankD pl_AtomicD_Add	(	PlankAtomicDRef	p,
		PlankD	operand
	)		[static]

Add a value to the current value.

Parameters:

p	The Plank AtomicD object.
operand	The value to add.

Returns:

The new value.

static PlankB pl_AtomicD_CompareAndSwap	(	PlankAtomicDRef	p,
		PlankD	oldValue,
		PlankD	newValue
	)		[static]

Swap the current value with a new value if a specified old value is still the current value.

This is the most important atomic operation for each atomic class, many other operations are based on this. If the operation fails the user would generally try again by getting the old value again and retrying to write the new value (e.g., in a loop) until successful. If there are no other threads contending to write the value the operation should succeed without blocking.

NB A bit-level comparison is performed. e.g., -0.0 and 0.0 would not be considered equal but two identical NaNs would be. In both of these cases this is different behaviour than comparing the two floating point values (i.e., -0.0 and 0.0 are considered equal and NaNs are never equal to anything else even if there's another identical NaN with which you are comparing).

Parameters:

p	The Plank AtomicD object.
oldValue	The expected old value being currently stored.
newValue	The new value to attempt to store.

Returns:

true if the swap was successful, otherwise false.

PlankAtomicDRef pl_AtomicD_Create

(

)

Create a Plank AtomicF object and return an oqaque reference to it.

Returns:

A Plank AtomicF object as an opaque reference or PLANK_NULL.

PlankAtomicDRef pl_AtomicD_CreateAndInit

(

)

Creates and initialises a Plank AtomicD object and return an oqaque reference to it.

Returns:

A Plank AtomicD object as an opaque reference or PLANK_NULL.

static PlankD pl_AtomicD_Decrement

(

PlankAtomicDRef

p

)

[static]

Decrement the current value by 1.

Parameters:

p	The Plank AtomicD object.

Returns:

The new value.

static PlankResult pl_AtomicD_DeInit

(

PlankAtomicDRef

p

)

[static]

Deinitialise a Plank AtomicD object.

Parameters:

p	The Plank AtomicD object.

Returns:

PlankResult_OK if successful, otherwise an error code.

PlankResult pl_AtomicD_Destroy

(

PlankAtomicDRef

p

)

Destroy a Plank AtomicD object.

Parameters:

p	The Plank AtomicD object.

Returns:

PlankResult_OK if successful, otherwise an error code.

static PlankD pl_AtomicD_Get

(

PlankAtomicDRef

p

)

[static]

Get the current value.

Parameters:

p	The Plank AtomicD object.

Returns:

The value.

PlankULL pl_AtomicD_GetExtra

(

PlankAtomicDRef

p

)

Not used for this class.

Parameters:

p	The Plank AtomicD object.

Returns:

Always returns 0.

PlankULL pl_AtomicD_GetExtraUnchecked

(

PlankAtomicDRef

p

)

Not used for this class.

Parameters:

p	The Plank AtomicD object.

Returns:

Always returns 0.

static PlankD pl_AtomicD_GetUnchecked

(

PlankAtomicDRef

p

)

[static]

Get the current value nonatomically.

Parameters:

p	The Plank AtomicD object.

Returns:

The value.

static PlankD pl_AtomicD_Increment

(

PlankAtomicDRef

p

)

[static]

Increment the current value by 1.

Parameters:

p	The Plank AtomicD object.

Returns:

The new value.

static PlankResult pl_AtomicD_Init

(

PlankAtomicDRef

p

)

[static]

Initialise a Plank AtomicD object.

Parameters:

p	The Plank AtomicD object.

Returns:

PlankResult_OK if successful, otherwise an error code.

static void pl_AtomicD_Set	(	PlankAtomicDRef	p,
		PlankD	newValue
	)		[static]

Set the current value to a new value.

Parameters:

p	The Plank AtomicD object.
newValue	The new value to store.

static PlankD pl_AtomicD_Subtract	(	PlankAtomicDRef	p,
		PlankD	operand
	)		[static]

Subtract a value from the current value.

Parameters:

p	The Plank AtomicD object.
operand	The value to subtract.

Returns:

The new value.

static PlankD pl_AtomicD_Swap	(	PlankAtomicDRef	p,
		PlankD	newValue
	)		[static]

Swap the current value with a new value.

Parameters:

p	The Plank AtomicD object.
newValue	The new value to store.

Returns:

The previously stored value.

static void pl_AtomicD_SwapOther	(	PlankAtomicDRef	p1,
		PlankAtomicDRef	p2
	)		[static]

Swap over two values.

The contents of p1 is copied to p2 and p2 is copied to p1 in an atomic operation.

Parameters:

p1	One Plank AtomicD object.
p2	The other Plank AtomicD object.