Hi Eli,
I've pulled the sources to the Cygnus library to investigate this
problem a little further, and the buffer accessibility check is not
occurring in the Cygnus implementation of "read" as I had thought.
Instead, it is the Win32 API call "ReadFile" that is doing the check and
returning the error. Specifically, ReadFile is returning error 998,
"Invalid access to memory location." The Cygnus library is simply mapping
this to an errno number (EACCES in this case). So the check is occurring
within Windows NT and not within the Cygnus library.
I haven't tried this under Windows 98, but under Windows NT at least,
it appears thatn one must specify a valid buffer when reading a file, even
if, by some magic, the programmer knows that the inaccessible part of the
buffer won't be used.
-- Dave Bryan
