const golang.org/x/sys/unix.SIOCGIFMTU

2 uses

	golang.org/x/sys/unix (current package)
		syscall_darwin.go#L308: 	err := ioctl(fd, SIOCGIFMTU, uintptr(unsafe.Pointer(&ifreq)))
		zerrors_darwin_amd64.go#L1228: 	SIOCGIFMTU                        = 0xc0206933

The pages are generated with Golds v0.3.2-preview. (GOOS=darwin GOARCH=amd64)
Golds is a Go 101 project developed by Tapir Liu.
PR and bug reports are welcome and can be submitted to the issue list.
Please follow @Go100and1 (reachable from the left QR code) to get the latest news of Golds.