1 .\" Automatically generated by Pod::Man version 1.15
2 .\" Wed Feb 19 16:43:01 2003
5 .\" ======================================================================
6 .de Sh \" Subsection heading
14 .de Sp \" Vertical space (when we can't use .PP)
20 .ie \\n(.$>=3 .ne \\$3
24 .de Vb \" Begin verbatim text
29 .de Ve \" End verbatim text
34 .\" Set up some character translations and predefined strings. \*(-- will
35 .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
36 .\" double quote, and \*(R" will give a right double quote. | will give a
37 .\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used
38 .\" to do unbreakable dashes and therefore won't be available. \*(C` and
39 .\" \*(C' expand to `' in nroff, nothing in troff, for use with C<>
41 .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
45 . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
46 . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
59 .\" If the F register is turned on, we'll generate index entries on stderr
60 .\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and
61 .\" index entries marked with X<> in POD. Of course, you'll have to process
62 .\" the output yourself in some meaningful fashion.
65 . tm Index:\\$1\t\\n%\t"\\$2"
71 .\" For nroff, turn off justification. Always turn off hyphenation; it
72 .\" makes way too many mistakes in technical documents.
76 .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
77 .\" Fear. Run. Save yourself. No user-serviceable parts.
79 . \" fudge factors for nroff and troff
88 . ds #H ((1u-(\\\\n(.fu%2u))*.13m)
94 . \" simple accents for nroff and troff
104 . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
105 . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
106 . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
107 . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
108 . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
109 . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
111 . \" troff and (daisy-wheel) nroff accents
112 .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
113 .ds 8 \h'\*(#H'\(*b\h'-\*(#H'
114 .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
115 .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
116 .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
117 .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
118 .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
119 .ds ae a\h'-(\w'a'u*4/10)'e
120 .ds Ae A\h'-(\w'A'u*4/10)'E
121 . \" corrections for vroff
122 .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
123 .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
124 . \" for low resolution devices (crt and lpr)
125 .if \n(.H>23 .if \n(.V>19 \
138 .\" ======================================================================
141 .TH bio 3 "0.9.7a" "2003-02-19" "OpenSSL"
144 bio \- I/O abstraction
146 .IX Header "SYNOPSIS"
148 \& #include <openssl/bio.h>
152 .IX Header "DESCRIPTION"
153 A \s-1BIO\s0 is an I/O abstraction, it hides many of the underlying I/O
154 details from an application. If an application uses a \s-1BIO\s0 for its
155 I/O it can transparently handle \s-1SSL\s0 connections, unencrypted network
156 connections and file I/O.
158 There are two type of \s-1BIO\s0, a source/sink \s-1BIO\s0 and a filter \s-1BIO\s0.
160 As its name implies a source/sink \s-1BIO\s0 is a source and/or sink of data,
161 examples include a socket \s-1BIO\s0 and a file \s-1BIO\s0.
163 A filter \s-1BIO\s0 takes data from one \s-1BIO\s0 and passes it through to
164 another, or the application. The data may be left unmodified (for
165 example a message digest \s-1BIO\s0) or translated (for example an
166 encryption \s-1BIO\s0). The effect of a filter \s-1BIO\s0 may change according
167 to the I/O operation it is performing: for example an encryption
168 \&\s-1BIO\s0 will encrypt data if it is being written to and decrypt data
169 if it is being read from.
171 BIOs can be joined together to form a chain (a single \s-1BIO\s0 is a chain
172 with one component). A chain normally consist of one source/sink
173 \&\s-1BIO\s0 and one or more filter BIOs. Data read from or written to the
174 first \s-1BIO\s0 then traverses the chain to the end (normally a source/sink
177 .IX Header "SEE ALSO"
179 BIO_f_base64(3), BIO_f_buffer(3),
180 BIO_f_cipher(3), BIO_f_md(3),
181 BIO_f_null(3), BIO_f_ssl(3),
182 BIO_find_type(3), BIO_new(3),
184 BIO_push(3), BIO_read(3),
185 BIO_s_accept(3), BIO_s_bio(3),
186 BIO_s_connect(3), BIO_s_fd(3),
187 BIO_s_file(3), BIO_s_mem(3),
188 BIO_s_null(3), BIO_s_socket(3),