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21<h1 align="center">mtcp_read</h1>
22<!--
23<a href="#NAME">NAME</a><br>
24<a href="#SYNOPSIS">SYNOPSIS</a><br>
25<a href="#DESCRIPTION">DESCRIPTION</a><br>
26<a href="#RETURN VALUE">RETURN VALUE</a><br>
27<a href="#ERRORS">ERRORS</a><br>
28<a href="#AUTHORS">AUTHORS</a><br>
29<a href="#SEE ALSO">SEE ALSO</a><br>
30<a href="#COLOPHON">COLOPHON</a><br>
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33
34<h2>NAME
35<a name="NAME"></a>
36</h2>
37
38
39<p style="margin-left:11%; margin-top: 1em">mtcp_read
40&minus; read bytestream from an mTCP socket</p>
41
42<h2>SYNOPSIS
43<a name="SYNOPSIS"></a>
44</h2>
45
46
47<p style="margin-left:11%; margin-top: 1em"><b>#include
48&lt;mtcp_api.h&gt;</b></p>
49
50<p style="margin-left:11%; margin-top: 1em"><b>ssize_t
51mtcp_read(mctx_t</b> <i>mctx</i><b>, int</b>
52<i>sockid</i><b>, char *</b><i>buf</i><b>, size_t</b>
53<i>len</i><b>);</b></p>
54
55<h2>DESCRIPTION
56<a name="DESCRIPTION"></a>
57</h2>
58
59
60
61<p style="margin-left:11%; margin-top: 1em"><b>mtcp_read</b>()
62can be used to read up to <i>len</i> number of bytes from
63mTCP socket via socket descriptor <i>sockid</i> into the
64buffer starting at <i>buf.</i> It is the responsibility of
65the user to allocate memory for <i>buf</i> array.</p>
66
67<p style="margin-left:11%; margin-top: 1em">For cases when
68the total number of buffered unread bytes in the socket are
69less than <i>len,</i> <b>mtcp_read()</b> copies entire data
70to <i>buf</i> and returns the actual number of bytes that
71can be used by the application.</p>
72
73<p style="margin-left:11%; margin-top: 1em">An
74<b>mtcp_read</b>() call takes an additional argument named
75<i>mctx</i> that represents the per-core mTCP context in an
76application (see <b>mtcp_create_context()</b> for
77details).</p>
78
79<h2>RETURN VALUE
80<a name="RETURN VALUE"></a>
81</h2>
82
83
84<p style="margin-left:11%; margin-top: 1em">On success, the
85number of bytes read is returned. It is not an error if this
86number is smaller than the number of bytes requested; this
87may happen when the socket has fewer number of bytes
88buffered at that moment. On all errors, -1 is returned and
89<i>errno</i> is set appropriately.</p>
90
91<h2>ERRORS
92<a name="ERRORS"></a>
93</h2>
94
95
96<table width="100%" border="0" rules="none" frame="void"
97       cellspacing="0" cellpadding="0">
98<tr valign="top" align="left">
99<td width="11%"></td>
100<td width="12%">
101
102
103<p style="margin-top: 1em"><b>EBADF</b></p></td>
104<td width="3%"></td>
105<td width="74%">
106
107
108<p style="margin-top: 1em">The socket descriptor
109<i>sockid</i> is invalid.</p></td></tr>
110<tr valign="top" align="left">
111<td width="11%"></td>
112<td width="12%">
113
114
115<p><b>ENOTSOCK</b></p></td>
116<td width="3%"></td>
117<td width="74%">
118
119
120<p>The socket referred to by <i>sockid</i> has invalid
121<i>type</i></p> </td></tr>
122<tr valign="top" align="left">
123<td width="11%"></td>
124<td width="12%">
125
126
127<p><b>ENOTCONN</b></p></td>
128<td width="3%"></td>
129<td width="74%">
130
131
132<p>Th socket referred to by <i>sockid</i> is in a TCP state
133that disallows read operations.</p></td></tr>
134<tr valign="top" align="left">
135<td width="11%"></td>
136<td width="12%">
137
138
139<p><b>EAGAIN</b></p></td>
140<td width="3%"></td>
141<td width="74%">
142
143
144<p>The socket referred to by <i>sockid</i> does not have
145any available bytes in its buffer for reading.</p></td></tr>
146</table>
147
148<h2>AUTHORS
149<a name="AUTHORS"></a>
150</h2>
151
152
153<p style="margin-left:11%; margin-top: 1em">mOS
154development team &lt;[email protected]&gt;</p>
155
156<h2>SEE ALSO
157<a name="SEE ALSO"></a>
158</h2>
159
160
161
162<p style="margin-left:11%; margin-top: 1em"><b>mtcp_bind</b>(),
163<b>mtcp_listen</b>(), <b>mtcp_accept</b>(),
164<b>mtcp_connect</b>(), <b>mtcp_socket</b>(),
165<b>mtcp_write</b>()</p>
166
167<h2>COLOPHON
168<a name="COLOPHON"></a>
169</h2>
170
171
172<p style="margin-left:11%; margin-top: 1em">This page is
173part of mOS release 0.3 <i>docs</i> section. A description
174of the project, and information about reporting bugs, can be
175found at http://mos.kaist.edu/.</p>
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