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Groups > comp.lang.basic.visual.misc > #710

Re: EOF Marker

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> Got a bit of code that reads a text file, looks something like this:
>
> Open FilePath For Input As #FileNum
>    Do Until EOF(FileNum)
>    Line Input #FileNum, LineStr
>    DoSomething
>    Loop
> Close #FileNum


Text lines om a.txt file usually are separated by a two byte sequence CR-LF 
= carriage return - linefeed = cgr$(13) chr$(10) and the end of such a file 
is indicated by am EOF character - chr$(26).

Basic's Line Input reads until such a CR/LF sequence is encountered, and 
sets EOF to true if an EOF char occurs.

So if yo try to read a file including control characters and binary data 
(and not plain text) there is a good chance that your program encounters an 
EOF char and stops reading.

If that's your problem then you must do a binary read (OPEN ... FOR BINARY 
...)providing an input buffer of fixed length and check the CR/LF yourself. 
If a CR/LF occurs you can shorten the buffer and start next reading behind 
the CR/LF position else you have to read one more buffer.

Doing this, you can also read (and write) 'behind' the EOF char easily.

HTH
rokas 

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EOF Marker "Ivar" <ivar.ekstromer000@ntlworld.com> - 2012-01-03 14:04 +0000
  Re: EOF Marker "Auric__" <not.my.real@email.address> - 2012-01-03 15:05 +0000
    Re: EOF Marker "Ivar" <ivar.ekstromer000@ntlworld.com> - 2012-01-03 16:05 +0000
  Re: EOF Marker GS <gs@somewhere.net> - 2012-01-03 13:04 -0500
  Re: EOF Marker "Theo Tress" <rbk@online.de> - 2012-01-20 17:45 +0100

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