cfspeed(S)

cfspeed: cfgetispeed, cfgetospeed, cfsetispeed, cfsetospeed -- baud rate functions

Syntax

cc . . . -lc

#include  <termios.h>

speed_t cfgetospeed (termios_p)
struct termios *termios_p;

int cfsetospeed (termios_p, speed)
struct termios *termios_p;
speed_t speed;

speed_t cfgetispeed (termios_p)
struct termios *termios_p;

int cfsetispeed (termios_p, speed)
struct termios *termios_p;
speed_t speed;

Description

The following interfaces are provided for getting and setting the values of the input and output baud rates in the termios structure. The effects on the terminal device described below do not become effective until the tcsetattr function is called successfully.

The input and output baud rates are stored in the termios structure. The values shown in the following table are supported. The name symbols in this table are defined in <termios.h>.

Name Description Name Description

BO Hang up B600 600 baud

B50 50 baud B1200 1200 baud

B75 75 baud B1800 1800 baud

B110 110 baud B2400 2400 baud

B134 134.5 baud B4800 4800 baud

B150 150 baud B9600 9600 baud

B200 200 baud B19200 19200 baud

B300 300 baud B38400 38400 baud

Name	Description	Name	Description
BO	Hang up	B600	600 baud
B50	50 baud	B1200	1200 baud
B75	75 baud	B1800	1800 baud
B110	110 baud	B2400	2400 baud
B134	134.5 baud	B4800	4800 baud
B150	150 baud	B9600	9600 baud
B200	200 baud	B19200	19200 baud
B300	300 baud	B38400	38400 baud

The type speed_t is defined in <termios.h> and as an unsigned integral type.

The termios_p argument is a pointer to a termios structure. cfgetospeed returns the output baud rate stored in the termios structure pointed to by termios_p.

cfsetospeed sets the output baud rate stored in the termios structure pointed to by termios_p to speed. The zero baud rate, BO, is used to terminate the connection. If BO is specified, the modem control lines are no longer asserted. Normally, this disconnects the line.

cfgetispeed returns the input baud rate stored in the termios structure.

cfsetispeed sets the input baud rate stored in the termios structure to speed. If the input baud rate is set to zero, the input baud rate is specified by the value of the output baud rate. Both cfsetispeed and cfsetospeed return a value of zero if successful and -1 to indicate an error. Attempts to set unsupported baud rates are ignored, and it is implementation-defined whether an error is returned by any or all of cfsetispeed, cfsetospeed, or tcsetattr. This refers both to changes to baud rates not supported by the hardware, and to changes setting the input and output baud rates to different values if the hardware does not support this.

Standards conformance

cfgetispeed, cfgetospeed, cfsetispeed and cfsetospeed are conformant with:

IEEE POSIX Std 1003.1-1990 System Application Program Interface (API) [C Language] (ISO/IEC 9945-1) ;
and NIST FIPS 151-1 .