Author: brueffer Date: Tue May 11 17:02:12 2010 New Revision: 207923 URL: http://svn.freebsd.org/changeset/base/207923
Log: Document FIONREAD, FIONWRITE and FIONSPACE. Obtained from: NetBSD Submitted by: emaste MFC after: 1 week Modified: head/lib/libc/sys/ioctl.2 Modified: head/lib/libc/sys/ioctl.2 ============================================================================== --- head/lib/libc/sys/ioctl.2 Tue May 11 17:01:14 2010 (r207922) +++ head/lib/libc/sys/ioctl.2 Tue May 11 17:02:12 2010 (r207923) @@ -29,7 +29,7 @@ .\" .\" $FreeBSD$ .\" -.Dd July 14, 2007 +.Dd May 11, 2010 .Dt IOCTL 2 .Os .Sh NAME @@ -80,6 +80,30 @@ Macros and defines used in specifying an .Fa request are located in the file .In sys/ioctl.h . +.Sh GENERIC IOCTLS +Some generic ioctls are not implemented for all types of file +descriptors. +These include: +.Bl -tag -width "xxxxxx" +.It Dv FIONREAD int +Get the number of bytes that are immediately available for reading. +.It Dv FIONWRITE int +Get the number of bytes in the descriptor's send queue. +These bytes are data which has been written to the descriptor but +which are being held by the kernel for further processing. +The nature of the required processing depends on the underlying device. +For TCP sockets, these bytes have not yet been acknowledged by the +other side of the connection. +.It Dv FIONSPACE int +Get the free space in the descriptor's send queue. +This value is the size of the send queue minus the number of bytes +being held in the queue. +Note: while this value represents the number of bytes that may be +added to the queue, other resource limitations may cause a write +not larger than the send queue's space to be blocked. +One such limitation would be a lack of network buffers for a write +to a network connection. +.El .Sh RETURN VALUES If an error has occurred, a value of -1 is returned and .Va errno _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
