Index for Section 3

Alphabetical listing for B

Bottom of page

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
  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
  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
  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
  TBA

Index for Section 3

Alphabetical listing for B

Top of page