6 replies to this topic

[swathin2]

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

[ZekeDragon]

The file itself does not contain any information regarding whether you've opened it or not (unless you save that information in the file, then of course it does), so if you want to track whether a file has been opened in a certain session of using your program or not, what I'd use is a function that detects all the files your program can open in a folder and maintains a map of some kind indicating which ones have been opened and which ones haven't. For example, you could create a function with a static char pointer, that is calloc'd to however many files are in the indicated folder at the time the program is opened, and then set each value to 0. While you're using the program, any time the file is opened, you'd call that function again with the name/number of the file that you're opening, and it would look up which char indicates that the file has been opened or not, and if it hasn't, it sets it to true (IE not zero) and returns 0 (indicating that the file hadn't been opened previously). It it had, it doesn't change anything, and returns 1 (indicating that the file had been opened previously). You can use this to check and set whether it was opened. :)

[Aereshaa]

A simple method is to keep a list of filenames that the user has opened somewhere.

[theonejb]

Isn't there some sort of information attached to the file that tells us when it was last accessed? Sort of like the last modified time in Windows?

If there is, you could simply keep a list of file access times, and whenever your program is run, you could check the current access time with the saved one to see if the file has been accessed.

[Aereshaa]

Under unix, (linux & mac os x too), you can use the stat() function. stat

[veda87]

Aereshaa said:

Under unix, (linux & mac os x too), you can use the stat() function. stat

For Example:

veda@veda-desktop:~$ stat eg.c 

  File: `eg.c'

  Size: 337       	Blocks: 8          IO Block: 4096   regular file

Device: 808h/2056d	Inode: 489479      Links: 1

Access: (0644/-rw-r--r--)  Uid: ( 1000/    veda)   Gid: ( 1000/    veda)

Access: 2009-09-08 16:16:22.000000000 +0530

Modify: 2009-09-08 16:16:28.000000000 +0530

Change: 2009-09-08 16:16:28.000000000 +0530