how can we know whether a particular file is read or not using c programming.
for an example:
the file name = abcd.txt
the status of the file should be 0 if the person has not opened it and it should be changed to 1 after any one reads it
how can we do this
Check the time stamp, perhaps?
> how can we know whether a particular file is read or not using c programming.
In general, you can't.
Some file systems maintain a "last access", but that could mean anything (not just reading).
Then there is the problem of if the filesystem is mounted read-only, in which case the last access time directory entries won't be updated.
Then there is the whole "boot another OS" and read the file issue, not to mention "bypass the file system and read the raw disk" issue.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
On Windows, I saw some Windows API functions that you could subscribe to which notify you when a file is accessed. I forget their names, but you can look them up. I'm not sure about UNIX though.
"I am probably the laziest programmer on the planet, a fact with which anyone who has ever seen my code will agree." - esbo, 11/15/2008
"the internet is a scary place to be thats why i dont use it much." - billet, 03/17/2010
Hmmm. This came up tangentially today. There is a Glib function, g_io_add_watch(), which can be used with a "socket, pipe, or file". I've used it with a socket, but not a file; I would assume something has to be added to the file to trigger, but you never know.Originally Posted by cpjust
C programming resources:
GNU C Function and Macro Index -- glibc reference manual
The C Book -- nice online learner guide
Current ISO draft standard
CCAN -- new CPAN like open source library repository
3 (different) GNU debugger tutorials: #1 -- #2 -- #3
cpwiki -- our wiki on sourceforge
