Using Seek In a Macro

Several other tips in other issues of ExcelTips discuss opening, reading, writing, appending, and closing text files from within a macro. Another command associated with sequential text files is the Seek command. If used on an open file, Seek positions the internal file pointer at a specific character number in the file. The following code fragment is an example of how it is used:

Open "DOSTEXT.DAT" for Input as #1
iFileLen = LOF(1)
Seek 1, iFileLen / 2

These program lines use the LOF function to determine the length of the file. The last line then positions the internal file pointer half way through the file. All subsequent reading or writing of the file will take place from that position.

You can also use Seek as a function to determine your current position within a text file. This is what this code does:

iCurPos = Seek(1)

This command leaves the internal file pointer where it was, but sets iCurPos to a value representing how many characters into the file the pointer is. The iCurPos value is the position at which all subsequent reading and writing of the file will take place.