Cogs::UniqueValue< T > Struct Template Reference

A value that is cleared (zero-initialised) when it is moved from. More...

#include <UniqueValue.h>

Public Member Functions
	UniqueValue (const T &value)
	UniqueValue (const UniqueValue &)=delete
	UniqueValue (UniqueValue &&other) noexcept
UniqueValue &	operator= (const UniqueValue &)=delete
UniqueValue &	operator= (UniqueValue &&other) noexcept

Public Attributes
T	value = T(0)

Detailed Description

template<typename T>
struct Cogs::UniqueValue< T >

A value that is cleared (zero-initialised) when it is moved from.

Use this to give a primitive member move-transfer semantics — the value travels to the new owner and is reset in the old one, preventing duplicate action on the same resource.

Example (from Cogs.Core Texture): a texture may wrap an externally-provided GPU handle that it does not always own. A plain bool ownsHandle would be copied on move, causing both the moved-from and moved-to object to believe they own the handle and attempt to release it. UniqueValue<bool> solves this by clearing the flag in the moved-from object automatically:

struct Texture {
    intptr_t            externalHandle    = 0;
    UniqueValue<bool>   ownsExternalTexture{ false };
 
    Texture(Texture&&) = default; // ownsExternalTexture clears in moved-from
    ~Texture() {
        if (ownsExternalTexture.value)
            releaseHandle(externalHandle); // only called by the true owner
    }
};

Definition at line 32 of file UniqueValue.h.

Constructor & Destructor Documentation

UniqueValue() [1/2]

template<typename T >

Cogs::UniqueValue< T >::UniqueValue ( const T &  value )

inline

Definition at line 34 of file UniqueValue.h.

UniqueValue() [2/2]

template<typename T >

Cogs::UniqueValue< T >::UniqueValue ( UniqueValue< T > &&  other )

inlinenoexcept

Definition at line 36 of file UniqueValue.h.

Member Function Documentation

operator=()

template<typename T >

UniqueValue & Cogs::UniqueValue< T >::operator= ( UniqueValue< T > &&  other )

inlinenoexcept

Definition at line 39 of file UniqueValue.h.

Member Data Documentation

value

template<typename T >

T Cogs::UniqueValue< T >::value = T(0)

Definition at line 41 of file UniqueValue.h.

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The documentation for this struct was generated from the following file:

• D:/a/1/s/Cogs/Cogs.Foundation/Source/UniqueValue.h