Basic Binary File Does not Read Unless Placed into Exact Format it originated?

Question

Ok, check this out.  This just does not make any sense to me.  First, you'll need to run it and create the two files.  You're going to get an error at the close.  Now...here's what doesn't make any sense to me.  If you enable the disabled diagram and read that same file, you can look at how the file is being read and the data interpreted.  How is that any different and not causing an error?  I took the U8 and changed it back to its original Boolean Array[8] format and received no error.  Which means the data was read as a U8 at some point.  But...for whatever reason, cannot be read and displayed as a U8.  What's up with that?  What am I not understanding?
Remember, code does exactly what you tell it.
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Binary File Issue.vi ‏23 KB

Answer 1

DailyDose wrote:
Huh....no read and write.  Either read or write.  Gotcha.
Not quite.  It is a matter of where the file pointer is.
The file pointer is what location in the file will be read from or written to, depending on what you do next.  When you write to a file, the file pointer is set to be directly after what you just wrote.  So when you write a new file, the file pointer is at the end of the file.  So when you try to do a read when the file pointer is at the end of the file, an attempt of a read at the end of the file happens.  But there is nothing left for it to read.  Therefore you get an End Of File error.
So if you just added a Set File Position to set the file pointer to the start of the file, you can read your byte with no error.
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Binary File Issue_BD.png ‏25 KB