BLOB_ReadData

[Ruslan Zasukhin]

on 8/7/03 12:13, Trevor DeVore at lists at mangomultimedia.com wrote:

> Hi,
> 
> I have a question regarding the VXCMD and Blob_ReadData.  I am using the VXCMD
> with Revolution.  In the Valentina VXCMD Ref docs it says:
> 
> BLOB_ReadData( fldRef, MemBuffer, BytesToRead )
> .....
> Read from the BLOB field into MemBuffer the specifid number of bytes. You are
> responsible
> that BytesToRead is NOT greater than size of MemBuffer, otherwise you can get
> a
> crash or RAM corruption.
> 
> and gives this example:
> 
> put Valentina("BLOB_GetDataSize", fldPhotoRef ) into blobSize
> put Valentina("MemBuffer_Allocate", blobSize ) into blobValueRef
> get Valentina("BLOB_ReadData", fldPhotoRef , blobValueRef, blobSize )
> 
> What I am wondering is how to get at the data from the BLOB field in
> Revolution after it has been read into MemBuffer?  I have everything in my
> code working up to that point but now I'm stumped.

Hi Trevor,

Okay, I have check sources.

1)  BLOB_ReadData( fldRef, MemBuffer, BytesToRead )

this is old function, that was intended to live for Hypercard, SuprtCard.
This was weak attempt to access BLOB field.
Actually it can allow you just Read one BLOB and write to other.
Somedbody once have use such way to copt on db to other in the V4MD.


2) You need instead look on the new function that support BINARY feature of
MetaCard/revolution.

        Binary_ReadData( fldRef, varName, [HowMuch], [Offset] )

This function works with variable of Metacard.
In the VXCMD archive exists example that show how this works.


-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
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e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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