Hi All,

I am using linux kernel 2.4.26. I created a special character file using
in dev directory as mknod /dev/test c 50 0. Command is successful n i can see the file created in /dev/test.

Then I tried to open the file using open the file as

result = open("/dev/test", I_RDWR);

but it fails i get the error as Device not found and it comes as error Number 19 i.e. ENODEV.

I can not change my kernel(version). Kindly let me know if any other thing is missing. Anybody faced the similar problem.

Waiting for reply. Thanks in advance.

Regards,

Wable

"I created a special character file using in dev directory as mknod /dev/test c 50 0."

50 0 must correspond to a device driver in the kernel. Did you create a kernel device driver for 50 0?

"i get the error as Device not found and it comes as error Number 19 i.e. ENODEV."

This error probably means that there is no kernel device driver which corresponds to 50 0.

"Then I tried to open the file using open the file as
result = open("/dev/test", I_RDWR);"

I think that this statement should be:
result = open("/dev/test", O_RDWR);
but that is not your problem and it should have resulted in a compile error.

------------------
Steve Stites

Did you write the character device driver?

If so, did you register the device with major number 50 and minor number 0?
Use the following code to register the device with a major and minor number. Note the 0 will automatically assign major number. In your case use 50. The DEVICE_NAME is a string with the name of your device. fops is a file_operations struct.
int major = register_chrdev(0, DEVICE_NAME, &fops);

If not, how do you know the device is using major number 50 and minor number 0?

Hi cstrask and jailbailt,

Thanks for your reply. I opened device with o_ only sorry it was typo.

I got my problem resolved as i changed the .config setup to support appripriate devices while kernel compilation. Anyway thanks for the help.

Regards,

Wable