AXIS camera SDK with QVariant problem : cannot access private member declared inclass

[szysagittarius]

Hey, guys,

I am new here, I am playing with AXIS network camera using its SDK based on QT. I want to use its GetCurrentImage function to get the Image.

Below is the syntax of GetCurrentImage from AXIS SDK.

GetCurrentImage
Syntax
HRESULT GetCurrentImage(int theFormat, [C++]
VARIANT* theBuffer,
LONG* theBufferSize
);
Parameters
theFormat
Identifier specifiying the format of the image data. Values available are: 0 = JPEG, 1 = BMP (defined in the AMC_IMAGE_FORMAT enum in the type library).

theBuffer
The buffer where the image data is returned.

theBufferSize
Size of the image data buffer returned.

It looks like assigning the “theBuffer” field passing by reference, like the format below

var* var;
 
getCurrentImage(var){ 		// object-> dynamicallcall(“getCurrentImage(var)”)
 
var = … // which can not be seen by us, because I am using dynamiccall to call the method in AXIS SDK
 
}

var* var;

getCurrentImage(var){ 		// object-> dynamicallcall(“getCurrentImage(var)”)

var = … // which can not be seen by us, because I am using dynamiccall to call the method in AXIS SDK

}

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So I choose QVariant to do that

(1) In the .h file under public declaration,
QVariant* MediaBuffer;
long* MediaBufferSize;

(2) in the .cpp file
I first tried

axWidget->dynamicCall("GetCurrentImage(int, QVariant*, long*)",0,MediaBuffer, MediaBufferSize);

axWidget->dynamicCall("GetCurrentImage(int, QVariant*, long*)",0,MediaBuffer, MediaBufferSize);

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then I got the error report twice:

error: C2248: 'QVariant::QVariant' : cannot access private member declared in class 'QVariant'
e:\qt\4.8.5\src\corelib\kernel\qvariant.h:429: see declaration of 'QVariant::QVariant'
e:\qt\4.8.5\src\corelib\kernel\qvariant.h:93: see declaration of 'QVariant'
error: C2248: 'QVariant::QVariant' : cannot access private member declared in class 'QVariant'
e:\qt\4.8.5\src\corelib\kernel\qvariant.h:429: see declaration of 'QVariant::QVariant'
e:\qt\4.8.5\src\corelib\kernel\qvariant.h:93: see declaration of 'QVariant'

in the second time, I tried

QList<QVariant> varList;
varList << 0 << MediaBuffer << MediaBufferSize; 			// error report place
axWidget->dynamicCall("GetCurrentImage(int, QVariant*, long*)",varList);
axWidget->dynamicCall("GetCurrentImage(QList<QVariant>)",varList); // the same error report

QList<QVariant> varList;
varList << 0 << MediaBuffer << MediaBufferSize; 			// error report place
axWidget->dynamicCall("GetCurrentImage(int, QVariant*, long*)",varList);
axWidget->dynamicCall("GetCurrentImage(QList<QVariant>)",varList); // the same error report

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I got the same error report

Looking deeper at the qvariant.h,
In line 429 it is

private:
    // force compile error, prevent QVariant(bool) to be called
inline QVariant(void *) { Q_ASSERT(false); } 	// line 429

private:
    // force compile error, prevent QVariant(bool) to be called
inline QVariant(void *) { Q_ASSERT(false); } 	// line 429

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in line 93
it is

class Q_CORE_EXPORT QVariant

class Q_CORE_EXPORT QVariant

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which I do not list all stuff here.

It seems the problem of the usage of QVariant up to now, but I do not know how can I fix it.

Could you guys give me some suggestions?


My environment is
Qt 4.8.5
Qtcreator 3.1.0
Win 8
AXIS Media Control API 6.30


Many thanks,
szysagittarius