.TH mtcp_ioctl 3 2017-02-02 "Linux" "mOS Library Functions Manual"
.SH NAME
mtcp_ioctl \- control mTCP socket
.SH SYNOPSIS
.B #include <mtcp_api.h>
.sp
.BI "int mtcp_ioctl(mctx_t " mctx ", int " sockid ", int " request ", void * " argp );

.SH DESCRIPTION
.BR mtcp_ioctl ()
can be used to retrieve certain attributes from an mTCP (of type SOCK_STREAM)
socket via descriptor id,
.I "sockid." 
The third argument,
.I "request"
is used by the caller to fetch the attribute type. The fourth argument,
.I "argp"
is an untyped pointer to memory that
.BR mtcp_ioctl ()
uses for storing the returning value.

Currently,
.BR mtcp_ioctl ()
only supports 1 type of
.I "request." 

.TP 12
.B FIONREAD
The number of bytes that can be read from the receive buffer when
.BR mtcp_read ()
is called. The user should pass 
.I "argp"
pointing to a memory region that can store a variable of size
.BR ssize_t .

.PP

Note that
.BR "mtcp_ioctl()"
assumes that the CPU core-id (as set inside
.I "mctx"
structure) will be used as the value for NIC queue-id,
which the mTCP context will eventually access during 
its operation. For example, mTCP context running on
core 3 will read traffic from NIC hardware queue-id 3.
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.SH RETURN VALUE
Returns 0 on success; -1 on failure. In case
of failure,
.I "errno"
is set appropriately.
.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.SH ERRORS
.TP 12
.B EACCES
.I "mctx"
is invalid

.TP 12
.B EBADF
.I "sockid"
is invalid.

.TP 12
.B "EFAULT"
.I "argp"
is NULL.
.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.\""""".SH CONFORMING TO
.\"""""POSIX.1-2001.
.SH AUTHORS
mOS development team <mtcp-user@list.ndsl.kaist.edu>
.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.SH SEE ALSO
.BR mtcp_getsockopt (),
.BR mtcp_socket (),
.BR mtcp_read ()
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.SH COLOPHON
This page is part of mOS release 0.3
.I "docs"
section. A description of the project, and information
about reporting bugs, can be found at
\%http://mos.kaist.edu/.
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