set MTU in C programmatically

Question

A client requested that the MTU limit should be 1492.

Is there a way to do it in the source code (program in C)?

Is there any other way to do it in general? (if

Answer 1

the modern way to set interface parameters is via sysfs

sudo sh -c 'echo 1492 > /sys/class/net/tun/mtu'

By C, just open and write as files