NAME    [Toc]    [Back]

       BIO_f_buffer - Buffering BIO

SYNOPSIS    [Toc]    [Back]

       #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    [Toc]    [Back]

       The BIO_f_buffer()  function  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.

       The BIO_get_buffer_num_lines() function returns the number
       of lines buffered.

       The                            BIO_set_read_buffer_size(),
       BIO_set_write_buffer_size()   and    BIO_set_buffer_size()
       functions  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.

       The  BIO_set_buffer_read_data()  function  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    [Toc]    [Back]

       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().  The  BIO_flush()  function
       might  need  to be retried if the ultimate source/sink BIO
       is non blocking.

RETURN VALUES    [Toc]    [Back]

       BIO_f_buffer() returns the buffering BIO method.

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

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

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

SEE ALSO    [Toc]    [Back]

       TBA



                                                  BIO_f_buffer(3)