SETEOF problem, perhapse a "bug"

[mark smit]

Hello,

I was trying to use the following code to presize a database file
but found that it didn't work the way I had hoped.

This example leaves the file at zero bytes...

#compile exe

function pbmain
    open"d:\mark.db" for random as #1 len = 1
    
    seek #1,50000
    seteof #1
    close #1
end function

And this example works just fine...

#compile exe

function pbmain
    open"d:\mark.db" for binary as #1
    
    seek #1,50000
    seteof #1
    close #1
end function

I would have though that they both would work the same way?

------------------
Cheers

[This message has been edited by mark smit (edited October 05, 2000).]

[Phil Tippit]

Mark,

It is not a bug, its the difference in the files that you
are trying to set the eof on.

For Random Files you will have to write a record to the
file at the record location, it must be the correct length
as specified in the open statement, but it can be all spaces

With Binary Files the SETEOF command must be the next byte
where a new record will go, not the end of the current record

Phil

Example Code Below:
In both cases the file lengths will be 50000 bytes.
Binary and Random Files are handled completely different.
It's strange, but this is how it works.
pbcc CODE

#COMPILE EXE

FUNCTION PBMAIN() AS LONG
    a$=" "  ' one record
    OPEN"c:\mark.db" FOR RANDOM AS #1 LEN = 1

    SEEK #1,50000
    PUT #1,,a$
    SETEOF #1
    PRINT "length #1 =";LOF(1)
    CLOSE #1
    '-------------------
    OPEN"c:\mark2.db" FOR BINARY AS #2

    SEEK #2,50001  ' actual end plus one for binary files
    SETEOF #2
    PRINT "length #2 =";LOF(2)
    CLOSE #2
    LINE INPUT "Press any key";a$
    '------------------
    a$=" "  ' one record

    OPEN"c:\mark.db" FOR RANDOM AS #1 LEN = 1

    SEEK #1,30000
    'GET #1,,a$    'get record 30000 if you want to save it.
    'SEEK #1,30000
    PUT #1,,a$
    SETEOF #1
    PRINT "length #1 =";LOF(1)
    CLOSE #1
    '----------------------
    OPEN"c:\mark2.db" FOR BINARY AS #2

    SEEK #2,30001  ' actual end plus one for binary files
    SETEOF #2
    PRINT "length #2 =";LOF(2)
    CLOSE #2
    LINE INPUT "Press any key";a$
END FUNCTION

[This message has been edited by Phil Tippit (edited October 05, 2000).]