open() and read() a file from sysfs

[krzaq <krzakers@gmail.com>]

Hi all!

I have a basic question with file opening.
I would like to make use of the data accessed from i2c sensors through sysfs.

Here's the code:

fd = open(/sys/bus/i2c/.../temp2_input,O_RDONLY);

while(1) {
  char[64] buf;
  read(fd,buf,siezof(buf));
  ...
  do_something
  ...
  sleep(5);
}

The thing is I always get the same reading in each read() :(.
When I do:
# cat /sys/bus/i2c.../temp2_input
I see that the temperature is changing, but my code still displays the
same reading.

So what's the deal? Why is it cached?
Am I supposed to open() and close() the file inside 'while' loop??
What's the proper way to do it?

-- 
Regards
Karol Krzak