Eric B. wrote:
all sorts of examples.
See also the autoconf manual.
What are you trying to conditionalize?
The tun/tap pseudo device is implemented very differently
on OSX vs LINUX, UNIX, et al.
Under LINUX et al, you open a single character device, usually
located at /dev/net/tun. Then, you use ioctl’s to to select
the pseudo network device name (tun0, tun1, tap0, tap1, etc) and
set the type (tun vs tap). There’s also an option for requesting
a name with the next available number (ie - tun%d or tap%d).
Under OSX, the tun/tap driver precreates the character devices
/dev/tun0 thru /dev/tun15 and /dev/tap0 thru /dev/tap15. The
application opens the appropriate character device to create the
associated pseudo network device of the same name and type.