Question

In my code NVRAM is implemented as character device and I want to give a condition to check whether it is character device or not. How to implement it programmatically? How can I do it through c++ code.

In terminal I gave command cat /proc/devices and it lists:

Character devices:
  1 mem
  4 /dev/vc/0
  4 tty
  4 ttyS
  5 /dev/tty
  5 /dev/console
  5 /dev/nvram

What does this number 5 in /dev/nvram denote?

Answer 1

The number denotes the device’s major number, and the Character devices: heading in that listing tells you it’s a character device.

If your character device is linked into the filesystem somewhere, like /dev/mydevice, you can also get information about it via the stat system call. The st_mode field of the struct stat structure can be tested with the S_ISCHR macro.