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132 .TH bio 3 "2007-03-15" "0.9.8e" "OpenSSL"
134 bio \- I/O abstraction
136 .IX Header "SYNOPSIS"
138 \& #include <openssl/bio.h>
143 .IX Header "DESCRIPTION"
144 A \s-1BIO\s0 is an I/O abstraction, it hides many of the underlying I/O
145 details from an application. If an application uses a \s-1BIO\s0 for its
146 I/O it can transparently handle \s-1SSL\s0 connections, unencrypted network
147 connections and file I/O.
149 There are two type of \s-1BIO\s0, a source/sink \s-1BIO\s0 and a filter \s-1BIO\s0.
151 As its name implies a source/sink \s-1BIO\s0 is a source and/or sink of data,
152 examples include a socket \s-1BIO\s0 and a file \s-1BIO\s0.
154 A filter \s-1BIO\s0 takes data from one \s-1BIO\s0 and passes it through to
155 another, or the application. The data may be left unmodified (for
156 example a message digest \s-1BIO\s0) or translated (for example an
157 encryption \s-1BIO\s0). The effect of a filter \s-1BIO\s0 may change according
158 to the I/O operation it is performing: for example an encryption
159 \&\s-1BIO\s0 will encrypt data if it is being written to and decrypt data
160 if it is being read from.
162 BIOs can be joined together to form a chain (a single \s-1BIO\s0 is a chain
163 with one component). A chain normally consist of one source/sink
164 \&\s-1BIO\s0 and one or more filter BIOs. Data read from or written to the
165 first \s-1BIO\s0 then traverses the chain to the end (normally a source/sink
168 .IX Header "SEE ALSO"
169 \&\fIBIO_ctrl\fR\|(3),
170 \&\fIBIO_f_base64\fR\|(3), \fIBIO_f_buffer\fR\|(3),
171 \&\fIBIO_f_cipher\fR\|(3), \fIBIO_f_md\fR\|(3),
172 \&\fIBIO_f_null\fR\|(3), \fIBIO_f_ssl\fR\|(3),
173 \&\fIBIO_find_type\fR\|(3), \fIBIO_new\fR\|(3),
174 \&\fIBIO_new_bio_pair\fR\|(3),
175 \&\fIBIO_push\fR\|(3), \fIBIO_read\fR\|(3),
176 \&\fIBIO_s_accept\fR\|(3), \fIBIO_s_bio\fR\|(3),
177 \&\fIBIO_s_connect\fR\|(3), \fIBIO_s_fd\fR\|(3),
178 \&\fIBIO_s_file\fR\|(3), \fIBIO_s_mem\fR\|(3),
179 \&\fIBIO_s_null\fR\|(3), \fIBIO_s_socket\fR\|(3),
180 \&\fIBIO_set_callback\fR\|(3),
181 \&\fIBIO_should_retry\fR\|(3)