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The and functions are provided for getting and setting
the termios structure. The and 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 function is called. Certain values
for baud rates set in the termios structure and passed to have special
meanings. These are discussed in the portion of the manual page that describes
the function.
The input and output baud
rates are found in the termios structure. The unsigned integer is typdef’d
in the include file 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 function
returns the input baud rate in the termios structure referenced by The
function sets the input baud rate in the termios structure referenced
by to The function returns the output baud rate in the termios structure
referenced by The function sets the output baud rate in the termios
structure referenced by to The function sets both the input and output
baud rate in the termios structure referenced by to Upon successful
completion, the functions and return a value of 0. Otherwise, a value
of -1 is returned and the global variable is set to indicate the error.
This section describes the functions
that are used to control the general terminal interface. Unless otherwise
noted for a specific command, these functions are restricted from use by
background processes. Attempts to perform these operations shall cause the
process group to be sent a SIGTTOU signal. If the calling process is blocking
or ignoring SIGTTOU signals, the process is allowed to perform the operation
and the SIGTTOU signal is not sent. In all the functions, although 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 function sets the flags stored in the termios structure
to a state disabling all input and output processing, giving a 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 setting raw mode with and the subsequent and then
using another with the saved state to revert to the previous terminal
state. The function copies the parameters associated with the terminal
referenced by in the termios structure referenced by This function is
allowed from a background process, however, the terminal attributes may
be subsequently changed by a foreground process. The function sets the
parameters associated with the terminal from the termios structure referenced
by The field is created by the following values, as specified in the
include file The change occurs immediately. The change occurs after
all output written to has been transmitted to the terminal. This value
of should be used when changing parameters that affect output. The change
occurs after all output written to has been transmitted to the terminal
Additionally, any input that has been received but not read is discarded.
If this value is into the value, the values of the and fields are
ignored. The 0 baud rate is used to terminate the connection. If 0 is specified
as the output speed to the function modem control will no longer be asserted
on the terminal, disconnecting the terminal. If zero is specified as the
input speed to the function the input baud rate will be set to the same
value as that specified by the output baud rate. If is unable able to
make any of the requested changes, it returns -1 and sets 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 and return
a value of 0. Otherwise, they return -1 and the global variable is set to
indicate the error, as follows: The argument to or was not a valid
file descriptor. The function was interrupted by a signal. The argument
to the function was not valid, or an attempt was made to change an attribute
represented in the termios structure to an unsupported value. The file
associated with the argument to or is not a terminal.
The
and functions are expected to be compliant with the specification.
The and functions, as well as the option to the function are extensions
to the specification.
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