opnsense-src/secure/lib/libcrypto/man/bio.3

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.IX Title "BIO 1"
.TH BIO 1 "perl v5.6.1" "2001-07-19" "User Contributed Perl Documentation"
.UC
.SH "NAME"
bio \- I/O abstraction
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/bio.h>
.Ve
\&\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"
BIO_ctrl(3),
BIO_f_base64(3), BIO_f_buffer(3),
BIO_f_cipher(3), BIO_f_md(3),
BIO_f_null(3), BIO_f_ssl(3),
BIO_find_type(3), BIO_new(3),
BIO_new_bio_pair(3),
BIO_push(3), BIO_read(3),
BIO_s_accept(3), BIO_s_bio(3),
BIO_s_connect(3), BIO_s_fd(3),
BIO_s_file(3), BIO_s_mem(3),
BIO_s_null(3), BIO_s_socket(3),
BIO_set_callback(3),
BIO_should_retry(3)