SEEK
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The SEEK statement sets the byte or record position in a file for the next read or write.
Syntax
- SEEK filenumber&, position
Parameters
- filenumber& must be the file number that is OPEN and being read or written to.
- position is a byte in BINARY or sequencial files created in OUTPUT, APPEND or INPUT modes. The first byte = 1.
- position is the record in RANDOM files to read or write. Records can hold more than one variable defined in a TYPE.
- Since the first SEEK file position is 1 it may require adding one to an offset value when documentation uses that position as 0.
- After a SEEK statement, the next file operation starts at that SEEK byte position.
- The SEEK statement can work with the SEEK (function) to move around in a file.
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 1
- A SEEK statement using the SEEK (function) to move to the next random record in a file.
SEEK 1, SEEK(1) + 1 |
- Example 2
- 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