1BIO_f_buffer(3)                     OpenSSL                    BIO_f_buffer(3)
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NAME

6       BIO_f_buffer - buffering BIO
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SYNOPSIS

9        #include <openssl/bio.h>
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11        BIO_METHOD * BIO_f_buffer(void);
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13        #define BIO_get_buffer_num_lines(b)    BIO_ctrl(b,BIO_C_GET_BUFF_NUM_LINES,0,NULL)
14        #define BIO_set_read_buffer_size(b,size) BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,0)
15        #define BIO_set_write_buffer_size(b,size) BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,1)
16        #define BIO_set_buffer_size(b,size)    BIO_ctrl(b,BIO_C_SET_BUFF_SIZE,size,NULL)
17        #define BIO_set_buffer_read_data(b,buf,num) BIO_ctrl(b,BIO_C_SET_BUFF_READ_DATA,num,buf)
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DESCRIPTION

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

44       Buffering BIOs implement BIO_gets() by using BIO_read() operations on
45       the next BIO in the chain. By prepending a buffering BIO to a chain it
46       is therefore possible to provide BIO_gets() functionality if the
47       following BIOs do not support it (for example SSL BIOs).
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49       Data is only written to the next BIO in the chain when the write buffer
50       fills or when BIO_flush() is called. It is therefore important to call
51       BIO_flush() whenever any pending data should be written such as when
52       removing a buffering BIO using BIO_pop(). BIO_flush() may need to be
53       retried if the ultimate source/sink BIO is non blocking.
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RETURN VALUES

56       BIO_f_buffer() returns the buffering BIO method.
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58       BIO_get_buffer_num_lines() returns the number of lines buffered (may be
59       0).
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61       BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and
62       BIO_set_buffer_size() return 1 if the buffer was successfully resized
63       or 0 for failure.
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65       BIO_set_buffer_read_data() returns 1 if the data was set correctly or 0
66       if there was an error.
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SEE ALSO

69       BIO(3), BIO_reset(3), BIO_flush(3), BIO_pop(3), BIO_ctrl(3),
70       BIO_int_ctrl(3)
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741.0.1e                            2013-02-11                   BIO_f_buffer(3)
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