Kernel module

taousif · 02-08-2011, 03:07 AM

Hi,

I have written a small character driver, in the cleanup module at the line

int a=unregister_chrdev(Major,DEVICE_NAME);

I am getting the following error
error: void value not ignored as it ought to be

If the value return by unregister_chrdev() function is not stored in any variable it is working fine...

Please help.
Thank you.

paulsm4 · 02-09-2011, 12:06 AM

Here is unregister_chr (from linux/fs.h):

Code:

static inline void unregister_chrdev(unsigned int major, const char *name)
{
        __unregister_chrdev(major, 0, 256, name);
}

It is a "void" function.

Meaning THERE IS NO RETURN VALUE.

Hence the message.

Trying to get the return value of a "void" function is an error.

'Hope that helps .. PSM

taousif · 02-09-2011, 11:30 PM

Thank you very much.