Pass '0' as the size argument and u will get the total size (sizeof struct * number of interfaces)
back. The only thing is u have to make two calls, which u would do anyway.

Balbir

Sebastian Heidl wrote:

>Hi,
>
>is there a specific reason for SIOCGIFCOUNT not being implemented
>in  the kernel ? All occurences lead to net/core/dev.c dev_ioctl(...)
>which just returns -EINVAL for this command. So one has to guess
>the number of struct ifreq structures to pass to a SIOCGIFCONF
>call.
>
>enlighten me, please ;-)
>_sh_
>