BIO_f_buffer(3) OpenSSL BIO_f_buffer(3) NNAAMMEE BIO_f_buffer - buffering BIO SSYYNNOOPPSSIISS #include 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) DDEESSCCRRIIPPTTIIOONN _B_I_O___f___b_u_f_f_e_r_(_) 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 _B_I_O___g_e_t_s_(_) and _B_I_O___p_u_t_s_(_) are supported. Calling _B_I_O___r_e_s_e_t_(_) on a buffering BIO clears any buffered data. _B_I_O___g_e_t___b_u_f_f_e_r___n_u_m___l_i_n_e_s_(_) returns the number of lines currently buffered. _B_I_O___s_e_t___r_e_a_d___b_u_f_f_e_r___s_i_z_e_(_), _B_I_O___s_e_t___w_r_i_t_e___b_u_f_f_e_r___s_i_z_e_(_) and _B_I_O___s_e_t___b_u_f_f_e_r___s_i_z_e_(_) set the read, write or both read and write buffer sizes to ssiizzee. The initial buffer size is DEFAULT_BUFFER_SIZE, cur- rently 4096. Any attempt to reduce the buffer size below DEFAULT_BUF- FER_SIZE is ignored. Any buffered data is cleared when the buffer is resized. _B_I_O___s_e_t___b_u_f_f_e_r___r_e_a_d___d_a_t_a_(_) clears the read buffer and fills it with nnuumm bytes of bbuuff. If nnuumm is larger than the current buffer size the buffer is expanded. NNOOTTEESS Buffering BIOs implement _B_I_O___g_e_t_s_(_) by using _B_I_O___r_e_a_d_(_) operations on the next BIO in the chain. By prepending a buffering BIO to a chain it is therefore possible to provide _B_I_O___g_e_t_s_(_) functionality if the fol- lowing 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 _B_I_O___f_l_u_s_h_(_) is called. It is therefore important to call _B_I_O___f_l_u_s_h_(_) whenever any pending data should be written such as when removing a buffering BIO using _B_I_O___p_o_p_(_). _B_I_O___f_l_u_s_h_(_) may need to be retried if the ultimate source/sink BIO is non blocking. RREETTUURRNN VVAALLUUEESS _B_I_O___f___b_u_f_f_e_r_(_) returns the buffering BIO method. _B_I_O___g_e_t___b_u_f_f_e_r___n_u_m___l_i_n_e_s_(_) returns the number of lines buffered (may be 0). _B_I_O___s_e_t___r_e_a_d___b_u_f_f_e_r___s_i_z_e_(_), _B_I_O___s_e_t___w_r_i_t_e___b_u_f_f_e_r___s_i_z_e_(_) and _B_I_O___s_e_t___b_u_f_f_e_r___s_i_z_e_(_) return 1 if the buffer was successfully resized or 0 for failure. _B_I_O___s_e_t___b_u_f_f_e_r___r_e_a_d___d_a_t_a_(_) returns 1 if the data was set correctly or 0 if there was an error. SSEEEE AALLSSOO _B_I_O(3), _B_I_O___r_e_s_e_t(3), _B_I_O___f_l_u_s_h(3), _B_I_O___p_o_p(3), _B_I_O___c_t_r_l(3), _B_I_O___i_n_t___c_t_r_l(3) 1.0.2u 2019-12-20 BIO_f_buffer(3)