🚀 go-pugleaf

Gambit:

Thanks for your detailed reply to my query. You have confirmed
most of my suspicions regarding the actions of ReadFile(), but
I still have some nagging questions.

>ReadFile() doesn't do anything with the data it reads. It is a straight
>copy-to-memory operation, copying from the file into your memory buffer.
>Whether or not the file data being read contains its own nulls, that is a
>completely different issue.

It is my understanding that ReadFile() is the same as the ANSI C
fread() function. Therefore, ReadFile() does a straight binary
read from the file into the memory buffer, given whatever size
of bytes is asked for.  So, ReadFile() has no way to tell if it
has read a null character, which may or may not be in the byte
stream it reads.

Thus, as you said:

>If the null is not present in the buffer, then SetWindowText()
>will just keep reading from memory until it finally encounters
>a null, or until it crashes with an access violation.  Either
>way, you'll be allowing SetWindowText() to potentially go outside
>the bounds of your buffer, thus producing undefined results.

But, after I took out the statements to append the null character
to the buffer in the Petzold code, I tested it by reading several
different text files to see if would crash and it didn't. I fully
expected it to crash on at least one of the files I read, so that
is why I started questioning what exactly was going on.

Now the question I have is when a string is written to a file, does
the null character also get written to the file. And if so, what is
its binary form.  That is, does the file maintain the sequence of
strings written to it? I will continue with my research into these
matters.

Thanks,

Bill