Name
Seek Procedure
Class
Microsoft.VisualBasic.FileSystem
Syntax
Seek(filenumber, position
)
-
filenumber
Use: Required
Data Type: Integer
Any valid file number
-
position
Use: Required
Data Type: Long
Any whole number between 1 and 2,147,483,647
Description
Places the read/write marker at a given position where the next read/write operation should occur
Rules at a Glance
If the file has been opened in Random mode,
position
refers to the next record number that should be read or written.In all other file open modes (Append, Binary, Input, and Output),
position
is the byte where the next read or write operation will start.The use of a record number in any subsequent
FileGet
orFilePut
procedure overrides the position set by theSeek
procedure.The size of a file can be increased as the result of a write operation that is performed after a call to the
Seek
procedure in whichposition
is beyond the end of the file.If
position
is 0 or negative, a runtime error will be generated.
Programming Tips and Gotchas
Unused records in a random-access data file are not necessarily blank. For example, if you open a brand new data file, then perform a seek operation to record number 10 and write a new record, the preceding 9 records will be filled with binary data that was present on the section of the disk used by the new file prior to its creation.
See Also
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