SEEK (function): Difference between revisions

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=== Notes ===
=== Notes ===
* Don't confuse the '''SEEK''' position with the [[LOC]] position !!
* Don't confuse the [[LOC]] position with the [[SEEK (function)|SEEK]] position !!
** '''LOC''' is the {{Text|last|red}} read or written byte or record prosition.
** '''SEEK''' is the byte or record prosition to read or write {{Text|next|red}}.
** '''SEEK''' is the byte or record prosition to read or write {{Text|next|red}}.
** '''LOC''' is the {{Text|last|red}} read or written byte or record prosition.




{{PageExamples}}
{{PageExamples}}
;Example:Demonstrate the difference between [[LOC]] and '''SEEK''' positions in a file.
;Example:Demonstrate the difference between '''LOC''' and '''SEEK''' positions in a file.
{{CodeStart}}
{{CodeStart}}
OPEN "readme.md" FOR BINARY AS #1
OPEN "readme.md" FOR BINARY AS #1

Latest revision as of 00:10, 25 February 2023

The SEEK function returns the byte or record position in a file, which is read or written next.


Syntax

byte = SEEK(filenumber&)


Parameters

  • filenumber& is the number of an OPEN file in any mode.
  • In RANDOM files SEEK returns the record position to read or write.
  • In BINARY or sequencial files SEEK returns the byte position to read or write (first byte = 1).
  • Since the first file position is 1 it may require adding one to an offset value when documentation uses that position as 0.
  • Devices that do not support SEEK (SCRN, CONS, KBRD, COMn and LPTn) return 0.

Notes

  • Don't confuse the LOC position with the SEEK position !!
    • LOC is the last read or written byte or record prosition.
    • SEEK is the byte or record prosition to read or write next.


Examples

Example
Demonstrate the difference between LOC and SEEK positions in a file.
OPEN "readme.md" FOR BINARY AS #1

PRINT LOC(1) 'LOC returns 0, as we didn't read something yet
PRINT SEEK(1) 'SEEK otherwise returns 1, as it's the first byte to read

GET #1, , a& 'now let's read a LONG (4 bytes)

PRINT LOC(1) 'now LOC returns 4, the last read byte
PRINT SEEK(1) 'and SEEK returns 5 now, the next byte to read

CLOSE #1
END
0
1
4
5


See also



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