BIO_f_buffer - Buffering BIO
BIO_METHOD * BIO_f_buffer(
void ); #define BIO_get_buffer_num_lines(b)
b,BIO_C_GET_BUFF_NUM_LINES,0,NULL ); #define
b,BIO_C_SET_BUFF_SIZE,size,0 ); #define
b,BIO_C_SET_BUFF_SIZE,size,1 ); #define
b,BIO_C_SET_BUFF_SIZE,size,NULL ); #define
The BIO_f_buffer() function returns the buffering BIO
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
The BIO_get_buffer_num_lines() function returns the number
of lines buffered.
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
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.
BIO_f_buffer() returns the buffering BIO method.
BIO_get_buffer_num_lines() returns the number of lines
buffered (may be 0).
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.
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