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V_RETRIEVE() / V_RET()
Return data that has been stored in a DBV file
-------------------------------------------------------------------------------
Syntax
V_RETRIEVE( <cPointer>,
[<nArea> | <cAlias>],
[<nStart>],
[<nCount>] ) -> Data
Arguments
<cPointer> is a six byte pointer-field (FlexFile's version of a
memo-field).
<nArea> or <cAlias> refers to the number or name of the target DBV
work area. If not specified, the current DBV work area is assumed.
<nStart> is the starting position in <cPointer>'s data. If
<nStart> is positive, it counts from the beginning of the data
pointed to by <cPointer>. If <nStart> is negative, it counts from
the end of the data pointed to by <cPointer>.
<nCount> is how many bytes of data to retrieve. If omitted,
<nCount> begins at <nStart> and goes to the end of the data. If
<nCount> is larger than the data, the excess is ignored.
Returns
V_RETRIEVE() will return the data pointed to by <cPointer>. On
error, V_RETRIEVE() will return an empty value of the type stored
or a logical (.F.) if no type can be determined. Use V_ERROR() to
fetch the error code associated with a failed RETRIEVE().
Description
V_RETRIEVE() retrieves data stored in a DBV type file. The data
retrieved will have the same type as the data that was stored
during the V_REPLACE() (with the notable exception of Clipper
arrays which are discussed below and Proclip windows which use the
V_WNDCREAT() function).
Notes
. Clipper arrays stored using the V_REPLACE() function cannot be
retrieved with V_RETRIEVE() when using the S87 compiler. Instead, use
V_FILLARR() for Summer 87 type arrays.
. <nStart> and <nCount> only apply to character data. They will
be ignored for any other data types.
Examples
// Open the DBF file and its associated DBV file
#define CR_LF ( CHR(13) + CHR(10) )
LOCAL cStr
USE dbf_file // Has a 6 byte pointer-field: vlf.
V_USE( "dbv_file" )// Is created if it does not exist.
cStr ="And the silken, sad, uncertain,"+ CR_LF +;
"rustling of each purple curtain,"+ CR_LF +;
"thrilled me, filled me," + CR_LF +;
"with fantastic terrors never felt before."
// Store the string in DBV file and its pointer in
// the DBF.
APPEND BLANK
REPLACE author WITH "Poe"
REPLACE poem WITH "The Raven"
REPLACE vlf WITH V_REPLACE( cStr, vlf )
// Edit the string using V_RETRIEVE().
cStr = MEMOEDIT( V_RETRIEVE( vlf ), 0, 0, 10, 45 )
// Save the edited poem.
REPLACE vlf WITH V_REPLACE( cStr, vlf )
See Also:
V_FILLARR()
V_REPLACE()
V_STUFF()
V_LEN()
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