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.\" ========================================================================
.\"
.IX Title "bio 3"
.TH bio 3 "2019-12-20" "1.0.2u" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
bio \- I/O abstraction
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/bio.h>
.Ve
.PP
\&\s-1TBA\s0
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
A \s-1BIO\s0 is an I/O abstraction, it hides many of the underlying I/O
details from an application. If an application uses a \s-1BIO\s0 for its
I/O it can transparently handle \s-1SSL\s0 connections, unencrypted network
connections and file I/O.
.PP
There are two type of \s-1BIO,\s0 a source/sink \s-1BIO\s0 and a filter \s-1BIO.\s0
.PP
As its name implies a source/sink \s-1BIO\s0 is a source and/or sink of data,
examples include a socket \s-1BIO\s0 and a file \s-1BIO.\s0
.PP
A filter \s-1BIO\s0 takes data from one \s-1BIO\s0 and passes it through to
another, or the application. The data may be left unmodified (for
example a message digest \s-1BIO\s0) or translated (for example an
encryption \s-1BIO\s0). The effect of a filter \s-1BIO\s0 may change according
to the I/O operation it is performing: for example an encryption
\&\s-1BIO\s0 will encrypt data if it is being written to and decrypt data
if it is being read from.
.PP
BIOs can be joined together to form a chain (a single \s-1BIO\s0 is a chain
with one component). A chain normally consist of one source/sink
\&\s-1BIO\s0 and one or more filter BIOs. Data read from or written to the
first \s-1BIO\s0 then traverses the chain to the end (normally a source/sink
\&\s-1BIO\s0).
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBBIO_ctrl\fR\|(3),
\&\fBBIO_f_base64\fR\|(3), \fBBIO_f_buffer\fR\|(3),
\&\fBBIO_f_cipher\fR\|(3), \fBBIO_f_md\fR\|(3),
\&\fBBIO_f_null\fR\|(3), \fBBIO_f_ssl\fR\|(3),
\&\fBBIO_find_type\fR\|(3), \fBBIO_new\fR\|(3),
\&\fBBIO_new_bio_pair\fR\|(3),
\&\fBBIO_push\fR\|(3), \fBBIO_read\fR\|(3),
\&\fBBIO_s_accept\fR\|(3), \fBBIO_s_bio\fR\|(3),
\&\fBBIO_s_connect\fR\|(3), \fBBIO_s_fd\fR\|(3),
\&\fBBIO_s_file\fR\|(3), \fBBIO_s_mem\fR\|(3),
\&\fBBIO_s_null\fR\|(3), \fBBIO_s_socket\fR\|(3),
\&\fBBIO_set_callback\fR\|(3),
\&\fBBIO_should_retry\fR\|(3)