MmeasAllocContext

Board	Supported
Host System	Yes
V4L2	Yes
Clarity UHD	Yes
Concord PoE	No
GenTL	Yes
GevIQ	Yes
GigE Vision	Yes
Indio	No
Iris GTX	Yes
Radient eV-CL	Yes
Rapixo CL	Yes
Rapixo CoF	Yes
Rapixo CXP	Yes
USB3 Vision	Yes

Allocate a measurement context.

Syntax

AIL_ID MmeasAllocContext(
    AIL_ID    SysId,        //in
    AIL_INT64 ControlFlag,  //in
    AIL_ID *  ContextIdPtr  //out
)

Description

This function allocates a measurement context on the specified system. Aurora Imaging Library uses a measurement context to control the behavior of measurement operations (MmeasFindMarker and MmeasCalculate). You can modify the settings of a measurement context with MmeasControl.

Aurora Imaging Library allows you to specify M_DEFAULT as the identifier of the measurement context, when using MmeasFindMarker, MmeasCalculate, and MmeasInquire; therefore, you need not call MmeasAllocContext. However, you cannot specify M_DEFAULT as the identifier of the measurement context if want to modify it using MmeasControl; to modify a measurement context, you must actually allocate it using MmeasAllocContext.

When the measurement context is no longer required, release it usingMmeasFreeunless M_UNIQUE_ID was specified during allocation; if M_UNIQUE_ID was specified, the smart identifier manages the measurement context's lifetime and you must not manually free it.

Parameters

SysId (in, AIL_ID)

Specifies the system on which the to allocate the measurement context.

For specifying the system identifier

Value	Description
M_DEFAULT_HOST	Specifies the default Host system of the current Aurora Imaging Library application.
System identifier	Specifies a valid system identifier, previously allocated using MsysAlloc.

ControlFlag (in, AIL_INT64)

Reserved for future expansion and must be set to M_DEFAULT.

ContextIdPtr *(out, AIL_ID)

Specifies the address of the variable in which to write the measurement context identifier or specifies the data type that the function should use to return the measurement context identifier.

For retrieving the identifier or specifying how to return it

Value	Description
M_NULL	Specifies that you will use this function's return value to obtain the identifier of the allocated measurement context; in this case, a standard Aurora Imaging Library identifier of type AIL_ID is returned.
M_UNIQUE_ID	Specifies that you will use this function's return value to obtain the identifier of the allocated measurement context; in this case, an Aurora Imaging Library smart identifier of type _AIL_UNIQUE_MEAS_ID_is returned instead of a standard Aurora Imaging Library identifier.This setting is only available when using C++11 (or later).An Aurora Imaging Library smart identifier manages the lifespan of the Aurora Imaging Library object it owns (similar to a std::unique_ptr). Note, you can use an Aurora Imaging Library smart identifier as though it were a standard Aurora Imaging Library identifier, except that you cannot use it to manually free the measurement context (it is freed automatically). For more information, see Aurora Imaging Library smart identifiers.
Address in which to write the identifier	Specifies the address of an AIL_ID in which to write the identifier of the allocated measurement context.

If allocation fails, M_NULL is written as the identifier. |

Return Value

Type: AIL_ID

The returned value is the measurement context identifier either as a standard identifier (AIL_ID) or a smart identifier (AIL_UNIQUE_MEAS_ID). If allocation fails, M_NULL is returned (or nullptr ifM_UNIQUE_ID was specified).