sp::RAIIObject< AllocType, CTorArgs > Class Template Reference

A generic mechanism for giving RAII semantics to C-style APIs. More...

#include <RAII.hpp>

Inheritance diagram for sp::RAIIObject< AllocType, CTorArgs >:

Public Member Functions
	RAIIObject (const CTorArgs &... args)
	Allocate a new object and take ownership of it. More...
	RAIIObject (const APIType &obj, bool own=true)
	Wrap an existing object. More...
const APIType	get () const
	Get the underlying C API object (eg. cudaStream_t) More...
APIType	get ()
	Get the underlying C API object (eg. cudaStream_t) More...
APIType	operator* ()
const APIType	operator* () const
	operator APIType () const
	Implicitly convert to the C API type, so you can just pass this object to the C library whence it came. More...
	operator APIType ()

Protected Types
using	APIType = typename AllocType::APIType
	The C API type. Something like cudaStream_t. More...
using	UnderlyingType = std::remove_pointer_t< APIType >

Detailed Description

template<typename AllocType, typename... CTorArgs>
class sp::RAIIObject< AllocType, CTorArgs >

A generic mechanism for giving RAII semantics to C-style APIs.

If you have a C API that works like this:

makeThingy(Thingy** output);
destroyThingy(Thingy* input);

You can write an allocator class wrapping makeThingy() and destroyThingy() with this signature:

struct ThingyAllocator {
    Thingy* create();
    void destroy(const Thingy*);
}

You can then instantiate RAIIObject<Thingy*, ThingyAllocator> and have RAII semantics for Thingy, thus eliminating many of the nightmares associated with using C APIs which have their own allocation functions .

This class defines operators allowing implicit conversion to the underlying C API type, allowing you to directly pass an RAIIObject<...> to functions of the C library you've wrapped.

Note

C APIs that work in this fashion typically give a nice name to Thingy* and give you that as the API object for you to play with. For instance, all NVIDIA® CUDA® APIs work like this: cudaStream_t is secretly pointer to a magic internal struct, for example.

Template Parameters

AllocType

A wrapper type around the C allocate/deallocate functions.

Member Typedef Documentation

APIType

template<typename AllocType , typename... CTorArgs>

using sp::RAIIObject< AllocType, CTorArgs >::APIType = typename AllocType::APIType

protected

The C API type. Something like cudaStream_t.

Constructor & Destructor Documentation

RAIIObject() [1/2]

template<typename AllocType , typename... CTorArgs>

sp::RAIIObject< AllocType, CTorArgs >::RAIIObject ( const CTorArgs &...  args )

explicit

Allocate a new object and take ownership of it.

RAIIObject() [2/2]

template<typename AllocType , typename... CTorArgs>

sp::RAIIObject< AllocType, CTorArgs >::RAIIObject ( const APIType &  obj, bool  own = true  )

explicit

Wrap an existing object.

This is mostly useful for writing glue code that bridges between C and C++ APIs.

Parameters

obj	The object to wrap.
own	If true, ownership is taken of the object. This is almost always desirable.

Member Function Documentation

get() [1/2]

template<typename AllocType , typename... CTorArgs>

APIType sp::RAIIObject< AllocType, CTorArgs >::get

(

)

Get the underlying C API object (eg. cudaStream_t)

get() [2/2]

template<typename AllocType , typename... CTorArgs>

const APIType sp::RAIIObject< AllocType, CTorArgs >::get

(

)

const

Get the underlying C API object (eg. cudaStream_t)

operator APIType()

template<typename AllocType , typename... CTorArgs>

sp::RAIIObject< AllocType, CTorArgs >::operator APIType

(

)

const

Implicitly convert to the C API type, so you can just pass this object to the C library whence it came.