Repositions the file pointer for a sequential file.
By default, SEEK
repositions the file pointer to the beginning of the file. SEEK
can be used to increment or decrement the file pointer from its current position, or from the beginning or end of the file.
You can optionally specify a THEN clause, an ELSE clause, or both a THEN and an ELSE clause. If the pointer reposition is successful, the THEN clause is executed. If pointer reposition fails (usually because the specified position is beyond the limits of the file), the ELSE clause is executed and the pointer position remains unchanged. The statements
argument can be the NULL
keyword, a single statement, or a block of statements terminated by the END
keyword. A block of statements has specific line break requirements: each statement must be on its own line and cannot follow a THEN, ELSE, or END keyword on that line.