4D Doc Center : EXPAND BLOB

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4D v14.3

BLOB

EXPAND BLOB


EXPAND BLOB ( blob )

Parameter	Type	Description
blob	BLOB	BLOB to expand

Description

The EXPAND BLOB command expands the BLOB blob that was previously compressed using the COMPRESS BLOB command.

After the call, the OK variable is set to 1 if the BLOB has been expanded. If the expansion could not be performed, the OK variable is set to 0.

If the expansion could not be performed because of a lack of memory, no error is generated and the method resumes its execution.
In any other case (i.e. the BLOB has not been compressed or is damaged), the error -10600 is generated. This error can be trapped using the ON ERR CALL command.

To check if a BLOB has been compressed, use the BLOB PROPERTIES command.

Example 1

This example tests if the BLOB vxMyBlob is compressed and, if so, expands it:

 BLOB PROPERTIES(vxMyBlob;$vlCompressed;$vlExpandedSize;$vlCurrentSize)

 If($vlCompressed#Is not compressed)

    EXPAND BLOB(vxMyBlob)

 End if

Example 2

This example allows you to select a document and then expand it, if it is compressed:

 $vhDocRef :=Open document("")

 If(OK=1)

    CLOSE DOCUMENT($vhDocRef)

    DOCUMENT TO BLOB(Document;vxBlob)

    If(OK=1)

       BLOB PROPERTIES(vxBlob;$vlCompressed;$vlExpandedSize;$vlCurrentSize)

       If($vlCompressed#Is not compressed)

          EXPAND BLOB(vxBlob)

          If(OK=1)

             BLOB TO DOCUMENT(Document;vxBlob)

          End if

       End if

    End if

 End if

System variables and sets

The OK variable is set to 1 if the BLOB has been successfully expanded, otherwise it is set to 0.