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Get the contents of a BLOB, identified by its memo field number
BLOBGet(<nFieldPos>, [<nStart>], [<nCount>]) --> uBLOB
<nFieldPos> is the position of the field in the database file
<nStart> is the starting position in the memo field of the BLOB
data. If <nStart> is positive, the starting position is relative to the
leftmost character in <nFieldPos>. If <nStart> is negative, it is
relative to the rightmost character in <nFieldPos>. If <nStart> is
omitted, it is assumed to be 1.
<nCount> is the number of bytes of data to retrieve beginning at
<nStart>. If <nCount> is larger than the amount of data stored, excess
data is ignored. If omitted, BLOBGET() retrieves to the end of the
Note: <nStart> and <nCount> apply to string data only. They are
ignored for any other data types.
BLOBGET() returns the BLOB data retrieved from the memo field. The data
type of the return value depends on the actual data stored. Use
VALTYPE() to determine the data type. If the indicated field is not a
memo field, BLOBGET() returns NIL.
BLOBGET() is very similar to FIELDGET(). However, because string type
variables cannot be larger than 64 KB, FIELDGET() will raise a runtime
error when attempting to retrieve memo fields of this magnitude or
BLOBGET() will also raise an error if you attempt to retrieve a field
greater than this magnitude; however, you can retrieve any subset of the
BLOB data by using an <nCount> less than 64 KB.
Note: BLOB data less than 64 KB can be retrieved from a memo field
using standard means (for example, referring to the field by name in an
expression or using the FIELDGET() function).
By default, this function operates on the currently selected work area.
It can be made to operate on an unselected work area by specifying it
within an aliased expression.
. This example imports information from a word processing
document into a field, then uses BLOBGET() to extract the first 25
characters of the field:
USE customer NEW VIA "DBFCDX"
// Field that contains word processor
nPos := FieldPos("WP_DOC")
// Import a file (can be larger than 64 KB), then
// obtain the first 25 characters to show to the
IF BLOBImport(nPos, "c:\application\temp.doc")
cStr := BLOBGet(nPos, 1, 25)
cStr := "Error: could not import file!"
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