From:	"Peter Remmers" <Peter DOT Remmers AT t-online DOT de>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: libsocket: difference between O_NONBLOCK and FIONBIO?
Date:	Tue, 3 Oct 2000 12:51:36 +0200
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Richard Dawe <rich AT phekda DOT freeserve DOT co DOT uk> schrieb...
> Hello.
>
> Peter Remmers wrote:
> > What exactly is the difference between the two?
> > The libsocket documentation talks about "similar":
>
> They can both be used to set non-blocking mode, as you know. However,
> fcntl()'s F_SETFL will set multiple options simultaneously. You should do
> something like:
>
>     int opts;
>
>     opts  = fcntl(sock, F_GETFL);
>     opts |= O_NONBLOCK;
>     if (fcntl(sock, F_SETFL, opts) < 0) {
>         /* error */
>     }

got it.

> In the libsocket the fcntl() support actually goes through the ioctl()
> code. fcntl(..., O_NONBLOCK) traverses the same code path as ioctl(...,
> FIONBIO, ...). So they have the same effect.

hmm, okay. In your particular implementation of the BSD sockets API
it's the same. But what about real unixes?

> Would things be clearer if the libsocket docs used 'like' instead of
> 'similar'? How do you think the docs could be improved?

That would help a lot. Actually, what you just wrote would make it
very clear :-)

Peter

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