Re: [Discuss-gnuradio] Compiler preprocessor defines

[Ed Criscuolo]

Eric Blossom wrote:
> On Mon, Nov 03, 2008 at 02:16:10PM -0500, Ed Criscuolo wrote:
> > Is there any preprocessor define (or defines) that can be used
> > when compiling C++ GnuRadio code to differentiate between
> > different OSs?  I've looked through config.h but didn't see
> > anything obvious.  I need to compile two different pieces
> > of code for OSX vs LINUX.
>
> FWIW, the "autoconf way" is to test for features, not OS's.
> In any event, if you look through config/*.m4 directory you'll find
> 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.


@(^.^)@  Ed