*BSD News Article 45056


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From: yzalkow@fox.ee.vt.edu (Yuval Zalkow)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Help with IOCTL programming, easy
Date: 6 Jun 1995 16:08:01 GMT
Organization: Virginia Tech, Blacksburg, Virginia
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Message-ID: <3r1uh1$at0@solaris.cc.vt.edu>
NNTP-Posting-Host: fox.ee.vt.edu
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Hello,

	I am working on writing a little program and I want to be able to check
the status of the modem line, whether it is still connected or not.  I got to
the point where I read the IOCTL man page and then looked through some of the
system header files.  I think I want to use IOCTL and send it the TIOCMODG
parameter to check the status of the port and then compare the result to
TIO_CAR or TIO_CD, which are the same, to tell me if I have a carrier.

Unfortunately, that's the depth of my knowledge, I don't completely understand
the parameter list to IOCTL, what's that last parameter *argp?  I would really
appreciate it if someone could write me a tiny little code fragment that would
explain this.

I wasn't really sure if this was the right place to ask, if it isn't, please
point me in the right direction.

Thank you, very much, in advance,
Chris Inacio
----------------
cinacio@vt.edu