Commit | Line | Data |
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1e7e4330 | 1 | .\" -*-nroff-*- |
fbf20b5b | 2 | .TH selpk 3 "23 May 1999" "Straylight/Edgeware" "mLib utilities library" |
1e7e4330 | 3 | .SH NAME |
4 | selpk \- packet-buffering input selector | |
5 | .\" @selpk_enable | |
6 | .\" @selpk_disable | |
7 | .\" @selpk_want | |
8 | .\" @selpk_init | |
9 | .\" @selpk_destroy | |
10 | .SH SYNOPSIS | |
11 | .nf | |
12 | .B "#include <mLib/selpk.h>" | |
13 | ||
14 | .BI "void selpk_enable(selpk *" pk ); | |
15 | .BI "void selpk_disable(selpk *" pk ); | |
16 | .BI "void selpk_want(selpk *" pk ", size_t " sz ); | |
2b1924c2 MW |
17 | .ds mT \fBvoid selpk_init( |
18 | .BI "\*(mTselpk *" pk ", sel_state *" s ", int " fd , | |
19 | .BI "\h'\w'\*(mT'u'pkbuf_func *" func ", void *" p ); | |
1e7e4330 | 20 | .BI "void selpk_destroy(selpk *" b ); |
21 | .fi | |
22 | .SH DESCRIPTION | |
23 | The | |
24 | .B selpk | |
25 | subsystem is a selector which integrates with the | |
26 | .BR sel (3) | |
27 | system for I/O multiplexing. It reads packets from a file descriptor | |
28 | and passes them to a caller-defined function. It uses the packet buffer | |
29 | described in | |
30 | .BR pkbuf (3) | |
31 | to do its work: you should read about it in order to understand exactly | |
32 | how the packet buffer decides how much data is in each packet and the | |
33 | exact rules about what your packet handling function should and | |
34 | shouldn't do. | |
35 | .PP | |
36 | The data for a packet selector is stored in an object of type | |
37 | .BR selpk . | |
38 | This object must be allocated by the caller, and initialized using the | |
39 | .B selpk_init | |
40 | function. This requires a fair few arguments: | |
41 | .TP | |
42 | .BI "selpk *" pk | |
43 | Pointer to the | |
44 | .B selpk | |
45 | object to initialize. | |
46 | .TP | |
47 | .BI "sel_state *" s | |
48 | Pointer to a multiplexor object (type | |
49 | .BR sel_state ) | |
50 | to which this selector should be attached. See | |
51 | .BR sel (3) | |
52 | for more details about multiplexors, and how this whole system works. | |
53 | .TP | |
54 | .BI "int " fd | |
55 | The file descriptor of the stream the selector should read from. | |
56 | .TP | |
0daaeb18 | 57 | .BI "pkbuf_func *" func |
1e7e4330 | 58 | The |
59 | .I "packet handler" | |
0daaeb18 | 60 | function. It is given a pointer to each packet read from the file (or |
1e7e4330 | 61 | null to indicate end-of-file) and an arbitrary pointer (the |
62 | .I p | |
63 | argument to | |
64 | .B selpk_init | |
0daaeb18 | 65 | described below). See |
66 | .BR pkbuf (3) | |
67 | for full details. | |
1e7e4330 | 68 | .TP |
69 | .BI "void *" p | |
70 | A pointer argument passed to | |
71 | .I func | |
72 | for each packet read from the file. Apart from this, the pointer is not | |
73 | used at all. | |
74 | .PP | |
75 | The | |
76 | .B selpk | |
77 | selector is immediately active. Subsequent calls to | |
78 | .B sel_select | |
79 | on the same multiplexor will cause any packets read from the file to be | |
80 | passed to your handling function. This function can at any time call | |
81 | .B selpk_disable | |
82 | to stop itself from being called any more. The selector is then | |
83 | disengaged from the I/O multiplexor and won't do anything until | |
84 | .B selpk_enable | |
85 | is called. Note that | |
86 | .B selpk_enable | |
87 | may well immediately start emitting complete packets of text which were | |
88 | queued up from the last I/O operation: it doesn't necessarily wait for | |
89 | the next | |
90 | .B sel_select | |
91 | call. | |
92 | .PP | |
93 | The size of packets read by the buffer is set by calling | |
94 | .BR selpk_want . | |
95 | See | |
96 | .BR pkbuf (3) | |
97 | for more details about how packet buffering works. | |
98 | .PP | |
99 | When it's finished with, a packet selector must be destroyed by calling | |
100 | .BR selpk_destroy . | |
101 | .SH "SEE ALSO" | |
102 | .BR pkbuf (3), | |
103 | .BR sel (3), | |
104 | .BR selbuf (3), | |
105 | .BR mLib (3). | |
106 | .SH AUTHOR | |
9b5ac6ff | 107 | Mark Wooding, <mdw@distorted.org.uk> |