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BIO(3)		      DragonFly Library Functions Manual		BIO(3)

NAME

BIO -- I/O abstraction

SYNOPSIS

#include <openssl/bio.h>

DESCRIPTION

A BIO is an I/O abstraction, it hides many of the underlying I/O details from an application. If an application uses a BIO for its I/O, it can transparently handle SSL connections, unencrypted network connections and file I/O. There are two types of BIO, a source/sink BIO and a filter BIO. As its name implies, a source/sink BIO is a source and/or sink of data, examples include a socket BIO and a file BIO. A filter BIO takes data from one BIO and passes it through to another, or to the application. The data may be left unmodified (for example a mes- sage digest BIO) or translated (for example an encryption BIO). The effect of a filter BIO may change according to the I/O operation it is performing: for example an encryption BIO will encrypt data if it is being written to and decrypt data if it is being read from. BIOs can be joined together to form a chain (a single BIO is a chain with one component). A chain normally consist of one source/sink BIO and one or more filter BIOs. Data read from or written to the first BIO then traverses the chain to the end (normally a source/sink BIO).

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) DragonFly 4.7 July 17, 2014 DragonFly 4.7 BIO_PRINTF(3) OpenSSL BIO_PRINTF(3)

NAME

BIO_printf, BIO_vprintf, BIO_snprintf, BIO_vsnprintf - formatted output to a BIO

SYNOPSIS

#include <openssl/bio.h> int BIO_printf(BIO *bio, const char *format, ...) int BIO_vprintf(BIO *bio, const char *format, va_list args) int BIO_snprintf(char *buf, size_t n, const char *format, ...) int BIO_vsnprintf(char *buf, size_t n, const char *format, va_list args)

DESCRIPTION

BIO_printf() is similar to the standard C printf() function, except that the output is sent to the specified BIO, bio, rather than standard output. All common format specifiers are supported. BIO_vprintf() is similar to the vprintf() function found on many platforms, the output is sent to the specified BIO, bio, rather than standard output. All common format specifiers are supported. The argument list args is a stdarg argument list. BIO_snprintf() is for platforms that do not have the common snprintf() function. It is like sprintf() except that the size parameter, n, specifies the size of the output buffer. BIO_vsnprintf() is to BIO_snprintf() as BIO_vprintf() is to BIO_printf().

RETURN VALUES

All functions return the number of bytes written, or -1 on error. For BIO_snprintf() and BIO_vsnprintf() this includes when the output buffer is too small.

COPYRIGHT

Copyright 2017 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>. 1.1.1q 2022-07-05 BIO_PRINTF(3)

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