Functions simplifying calls that return a variable-length buffer/array. More...

Functions
template<typename T , typename F , typename... Args>
std::vector< T >	xrtraits::doTwoCall (F &&wrappedCall, Args &&... a)

template<typename T , typename F , typename... Args>
std::vector< T >	xrtraits::doTwoCallWithSizeHint (uint32_t sizeHint, F &&wrappedCall, Args &&... a)

template<typename T , typename F , typename... Args>
XrResult	xrtraits::doTwoCallInPlace (std::vector< T > &container, F &&wrappedCall, Args &&... a)

Detailed Description

Functions simplifying calls that return a variable-length buffer/array.

Some of these functions may take a leading argument, such as a size hint or a container to populate. However, after that possible argument, the rest are standardized:

wrappedCall is something callable (lambda or function). It will receive capacityInput, countOutput, and array parameters as its only (if no more arguments are passed to the function) or last (if additional parameters are passed) parameters.
Any additional arguments passed will be forwarded to the call before the capacityInput, countOutput, and array parameters.

Function Documentation

◆ doTwoCall()

template<typename T , typename F , typename... Args>

std::vector<T> xrtraits::doTwoCall	(	F &&	wrappedCall,
		Args &&...	a
	)

inline

#include <xrtraits/TwoCall.h>

Perform the two call idiom, returning a vector.

Template Parameters

T	The type of the buffer element you expect

Parameters

wrappedCall	A function or lambda that takes the `capacityInput`, `countOutput`, and `array` parameters as its only or last parameters.
a	Any additional arguments passed to this call will be forwarded to the call before the `capacityInput`, `countOutput`, and `array` parameters.

Exceptions

if	final call does not return XR_SUCCESS

Requires XR_USE_EXCEPTIONS.

Examples:: twocall-function-and-one-arg.cpp, and twocall-just-function.cpp.

References xrtraits::make_zeroed_vector(), and xrtraits::exceptions::throwIfNotUnqualifiedSuccess().

◆ doTwoCallInPlace()

template<typename T , typename F , typename... Args>

XrResult xrtraits::doTwoCallInPlace	(	std::vector< T > &	container,
		F &&	wrappedCall,
		Args &&...	a
	)

inline

#include <xrtraits/TwoCall.h>

Perform the two call idiom, returning XrResult, to populate an existing container, whose size may hint at expected count.

Parameters

container	The container to fill. If it is not empty, the buffer size will be used as a size hint: if sufficient, only one call to the wrappedCall will be made.
wrappedCall	A function or lambda that takes the `capacityInput`, `countOutput`, and `array` parameters as its only or last parameters.
a	Any additional arguments passed to this call will be forwarded to the call before the `capacityInput`, `countOutput`, and `array` parameters.

Does not require XR_USE_EXCEPTIONS.

Examples:: twocall-in-place-just-function.cpp, and twocall-in-place-sized-and-initialized.cpp.

◆ doTwoCallWithSizeHint()

template<typename T , typename F , typename... Args>

std::vector<T> xrtraits::doTwoCallWithSizeHint	(	uint32_t	sizeHint,
		F &&	wrappedCall,
		Args &&...	a
	)

inline

#include <xrtraits/TwoCall.h>

Perform the two call idiom, returning a vector, when we already have a hint about the capacity.

Template Parameters

T	The type of the buffer element you expect

Parameters

sizeHint	The buffer size to attempt: if sufficient, only one call to the wrappedCall will be made.
wrappedCall	A function or lambda that takes the `capacityInput`, `countOutput`, and `array` parameters as its only or last parameters.
a	Any additional arguments passed to this call will be forwarded to the call before the `capacityInput`, `countOutput`, and `array` parameters.

Exceptions

if	final call does not return XR_SUCCESS

Requires XR_USE_EXCEPTIONS.

Examples:: twocall-size-hint-and-initialized.cpp.

References xrtraits::make_zeroed_vector(), and xrtraits::exceptions::throwIfNotUnqualifiedSuccess().