1BIO_F_BUFFER(3)                     OpenSSL                    BIO_F_BUFFER(3)
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NAME

6       BIO_get_buffer_num_lines, BIO_set_read_buffer_size,
7       BIO_set_write_buffer_size, BIO_set_buffer_size,
8       BIO_set_buffer_read_data, BIO_f_buffer - buffering BIO
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SYNOPSIS

11        #include <openssl/bio.h>
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13        const BIO_METHOD *BIO_f_buffer(void);
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15        long BIO_get_buffer_num_lines(BIO *b);
16        long BIO_set_read_buffer_size(BIO *b, long size);
17        long BIO_set_write_buffer_size(BIO *b, long size);
18        long BIO_set_buffer_size(BIO *b, long size);
19        long BIO_set_buffer_read_data(BIO *b, void *buf, long num);
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DESCRIPTION

22       BIO_f_buffer() returns the buffering BIO method.
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24       Data written to a buffering BIO is buffered and periodically written to
25       the next BIO in the chain. Data read from a buffering BIO comes from an
26       internal buffer which is filled from the next BIO in the chain.  Both
27       BIO_gets() and BIO_puts() are supported.
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29       Calling BIO_reset() on a buffering BIO clears any buffered data.
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31       BIO_get_buffer_num_lines() returns the number of lines currently
32       buffered.
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34       BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and
35       BIO_set_buffer_size() set the read, write or both read and write buffer
36       sizes to size. The initial buffer size is DEFAULT_BUFFER_SIZE,
37       currently 4096. Any attempt to reduce the buffer size below
38       DEFAULT_BUFFER_SIZE is ignored. Any buffered data is cleared when the
39       buffer is resized.
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41       BIO_set_buffer_read_data() clears the read buffer and fills it with num
42       bytes of buf. If num is larger than the current buffer size the buffer
43       is expanded.
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NOTES

46       These functions, other than BIO_f_buffer(), are implemented as macros.
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48       Buffering BIOs implement BIO_gets() by using BIO_read_ex() operations
49       on the next BIO in the chain. By prepending a buffering BIO to a chain
50       it is therefore possible to provide BIO_gets() functionality if the
51       following BIOs do not support it (for example SSL BIOs).
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53       Data is only written to the next BIO in the chain when the write buffer
54       fills or when BIO_flush() is called. It is therefore important to call
55       BIO_flush() whenever any pending data should be written such as when
56       removing a buffering BIO using BIO_pop(). BIO_flush() may need to be
57       retried if the ultimate source/sink BIO is non blocking.
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RETURN VALUES

60       BIO_f_buffer() returns the buffering BIO method.
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62       BIO_get_buffer_num_lines() returns the number of lines buffered (may be
63       0).
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65       BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and
66       BIO_set_buffer_size() return 1 if the buffer was successfully resized
67       or 0 for failure.
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69       BIO_set_buffer_read_data() returns 1 if the data was set correctly or 0
70       if there was an error.
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SEE ALSO

73       bio(7), BIO_reset(3), BIO_flush(3), BIO_pop(3), BIO_ctrl(3).
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76       Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
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78       Licensed under the OpenSSL license (the "License").  You may not use
79       this file except in compliance with the License.  You can obtain a copy
80       in the file LICENSE in the source distribution or at
81       <https://www.openssl.org/source/license.html>.
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851.1.1d                            2019-10-03                   BIO_F_BUFFER(3)
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