BIO_f_buffer(3)

     BIO_f_buffer(3)        0.9.6h (2000-09-18)        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 periodically
          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

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     BIO_f_buffer(3)        0.9.6h (2000-09-18)        BIO_f_buffer(3)

          ultimate source/sink BIO is non blocking.

     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

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