BIO_f_buffer(3)             OpenSSL             BIO_f_buffer(3)





NAME
       BIO_f_buffer - buffering BIO

SYNOPSIS
        #include <openssl/bio.h>

        BIO_METHOD * BIO_f_buffer(void);

        #define BIO_get_buffer_num_lines(b)    BIO_ctrl(b,BIO_C_GET_BUFF_NUM_LINES,0,NULL)
        #define BIO_set_read_buffer_size(b,size) BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,0)
        #define BIO_set_write_buffer_size(b,size) BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,1)
        #define BIO_set_buffer_size(b,size)    BIO_ctrl(b,BIO_C_SET_BUFF_SIZE,size,NULL)
        #define BIO_set_buffer_read_data(b,buf,num) BIO_ctrl(b,BIO_C_SET_BUFF_READ_DATA,num,buf)

DESCRIPTION
       BIO_f_buffer() returns the buffering BIO method.

       Data written to a buffering BIO is buffered and periodi-
       cally written to the next BIO in the chain. Data read
       from a buffering BIO comes from an internal buffer which
       is filled from the next BIO in the chain.  Both
       BIO_gets() and BIO_puts() are supported.

       Calling BIO_reset() on a buffering BIO clears any
       buffered data.

       BIO_get_buffer_num_lines() returns the number of lines
       currently buffered.

       BIO_set_read_buffer_size(), BIO_set_write_buffer_size()
       and BIO_set_buffer_size() set the read, write or both
       read and write buffer sizes to size. The initial buffer
       size is DEFAULT_BUFFER_SIZE, currently 1024. Any attempt
       to reduce the buffer size below DEFAULT_BUFFER_SIZE is
       ignored. Any buffered data is cleared when the buffer is
       resized.

       BIO_set_buffer_read_data() clears the read buffer and
       fills it with num bytes of buf. If num is larger than
       the current buffer size the buffer is expanded.

NOTES
       Buffering BIOs implement BIO_gets() by using BIO_read()
       operations on the next BIO in the chain. By prepending a
       buffering BIO to a chain it is therefore possible to
       provide BIO_gets() functionality if the following BIOs
       do not support it (for example SSL BIOs).

       Data is only written to the next BIO in the chain when
       the write buffer fills or when BIO_flush() is called. It
       is therefore important to call BIO_flush() whenever any
       pending data should be written such as when removing a
       buffering BIO using BIO_pop(). BIO_flush() may need to
       be retried if the ultimate source/sink BIO is non block-
       ing.

RETURN VALUES
       BIO_f_buffer() returns the buffering BIO method.

       BIO_get_buffer_num_lines() returns the number of lines
       buffered (may be 0).

       BIO_set_read_buffer_size(), BIO_set_write_buffer_size()
       and BIO_set_buffer_size() return 1 if the buffer was
       successfully resized or 0 for failure.

       BIO_set_buffer_read_data() returns 1 if the data was set
       correctly or 0 if there was an error.

SEE ALSO
       TBA



0.9.7c                     2000-09-19           BIO_f_buffer(3)
