| TCSETATTR(3) | Library Functions Manual | TCSETATTR(3) |
cfgetispeed, cfsetispeed,
cfgetospeed, cfsetospeed,
cfsetspeed, cfmakeraw,
tcgetattr, tcsetattr —
#include <termios.h>
speed_t
cfgetispeed(const
struct termios *t);
int
cfsetispeed(struct
termios *t, speed_t
speed);
speed_t
cfgetospeed(const
struct termios *t);
int
cfsetospeed(struct
termios *t, speed_t
speed);
int
cfsetspeed(struct
termios *t, speed_t
speed);
void
cfmakeraw(struct
termios *t);
int
tcgetattr(int
fd, struct termios
*t);
int
tcsetattr(int
fd, int action,
const struct termios
*t);
cfmakeraw, tcgetattr and
tcsetattr functions are provided for getting and
setting the termios structure.
The cfgetispeed,
cfsetispeed, cfgetospeed,
cfsetospeed and cfsetspeed
functions are provided for getting and setting the baud rate values in the
termios structure. The effects of the functions on the terminal as described
below do not become effective, nor are all errors detected, until the
tcsetattr function is called. Certain values for
baud rates set in the termios structure and passed to
tcsetattr have special meanings. These are discussed
in the portion of the manual page that describes the
tcsetattr function.
speed_t is typdef'd in the include file
<termios.h>. The value of the
integer corresponds directly to the baud rate being represented, however, the
following symbolic values are defined.
#define B0 0 #define B50 50 #define B75 75 #define B110 110 #define B134 134 #define B150 150 #define B200 200 #define B300 300 #define B600 600 #define B1200 1200 #define B1800 1800 #define B2400 2400 #define B4800 4800 #define B9600 9600 #define B19200 19200 #define B38400 38400 #ifndef _POSIX_SOURCE #define EXTA 19200 #define EXTB 38400 #endif /*_POSIX_SOURCE */
The cfgetispeed function returns the input
baud rate in the termios structure referenced by
tp.
The cfsetispeed function sets the input
baud rate in the termios structure referenced by tp to
speed.
The cfgetospeed function returns the
output baud rate in the termios structure referenced by
tp.
The cfsetospeed function sets the output
baud rate in the termios structure referenced by tp to
speed.
The cfsetspeed function sets both the
input and output baud rate in the termios structure referenced by
tp to speed.
Upon successful completion, the functions
cfsetispeed, cfsetospeed,
and cfsetspeed return a value of 0. Otherwise, a
value of -1 is returned and the global variable errno
is set to indicate the error.
In all the functions, although fd is an open file descriptor, the functions affect the underlying terminal file, not just the open file description associated with the particular file descriptor.
The cfmakeraw function sets the flags
stored in the termios structure (initialized by
tcgetattr) to a state disabling all input and output
processing, giving a “raw I/O path”. It should be noted that
there is no function to reverse this effect. This is because there are a
variety of processing options that could be re-enabled and the correct
method is for an application to snapshot the current terminal state using
the function tcgetattr, setting raw mode with
cfmakeraw and the subsequent
tcsetattr, and then using another
tcsetattr with the saved state to revert to the
previous terminal state.
The tcgetattr function copies the
parameters associated with the terminal referenced by
fd to the termios structure referenced by
tp. This function is allowed from a background
process, however, the terminal attributes may be subsequently changed by a
foreground process.
The tcsetattr function sets the parameters
associated with the terminal from the termios structure referenced by
tp. The action field is created
by or'ing the following values, as specified in the
include file
<termios.h>.
The 0 baud rate is used to terminate the connection. If 0 is
specified as the output speed to the function
tcsetattr, modem control will no longer be asserted
on the terminal, disconnecting the terminal.
If zero is specified as the input speed to the function
tcsetattr, the input baud rate will be set to the
same value as that specified by the output baud rate.
tcsetattr is unable to make any of the requested
changes, it returns -1 and sets errno. Otherwise, it makes all of the
requested changes it can. If the specified input and output baud rates differ
and are a combination that is not supported, neither baud rate is changed.
Upon successful completion, the functions
tcgetattr and tcsetattr
return a value of 0. Otherwise, they return -1 and the global variable
errno is set to indicate the error, as follows:
EBADF]tcgetattr
or tcsetattr was not a valid file descriptor.EINTR]tcsetattr function was interrupted by a
signal.EINVAL]tcsetattr function was not valid, or an attempt
was made to change an attribute represented in the termios structure to an
unsupported value.ENOTTY]tcgetattr or tcsetattr is
not a terminal.cfgetispeed, cfsetispeed,
cfgetospeed, cfsetospeed,
tcgetattr and tcsetattr
functions are expected to be compliant with the IEEE Std
1003.1-1988 (“POSIX.1”) specification. The
cfmakeraw and cfsetspeed
functions, as well as the TCSASOFT option to the
tcsetattr function are extensions to the
IEEE Std 1003.1-1988 (“POSIX.1”)
specification.
| May 1, 2004 | NetBSD 9.1 |