seek

#seek

##Syntax A seekStatement is one of:

(a) seek : fileNumber , filePosition (b) seek : fileNumber , *

##Description Random access of both source (ASCII or EBCDIC) and internal form (binary) files is provided by the seek and tell statements. The seek statement repositions the specified file so that the next input/output operation will begin at the specified point (filePosition) in the file.

The fileNumber must specify a file that is open with seek capability. The filePosition is a non-negative integer offset in bytes from the beginning of the file. Usually, this is a number returned by the tell statement. (The first position in the file is position zero.)

Form (b) specifies that the next operation is to begin at the position immediately following the current end of the file. A filePosition of zero specifies that the next operation is to start at the beginning of the file. Seeking to a position beyond the current end of the file and then writing, automatically fills the intervening positions with the internal representation of zero.

##Example This example shows how to use seek to append to the end of a file.

    var employeeRecord :
        record
            name : string ( 30 )
            pay : int
        end record
    var fileNo : int
    open : fileNo, "payroll", write, seek, mod
    seek : fileNo, *        % Seek to the end of the file
    write : fileNo, employeeRecord
                    % This record is added to the end of the file

##See also read.html, write.html, open.html, close.html, tell.html, get.html and put.html statements. Another example use of is given with the explanation of the tell.html statement.html.