tcsetattr - Set the parameters associated with the terminal
struct termios *termios_p );
Standard C Library (libc)
Interfaces documented on this reference page conform to
industry standards as follows:
tcsetattr(): XPG4, XPG4-UNIX
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Specifies an open file descriptor associated with a terminal.
Specifies the options defining how the parameters
will be set. Points to a termios structure containing the
The tcsetattr() function sets the parameters associated
with the terminal referred to by the open file descriptor
filedes from the termios structure referenced by termios_p
as follows: If optional_actions is TCSANOW, the change
will occur immediately. If optional_actions is TCSADRAIN,
the change will occur after all output written to filedes
has been transmitted. This function should be used when
changing parameters that affect output. If
optional_actions is TCSAFLUSH, the change will occur after
all output written to filedes has been transmitted, and
all input so far received but not read will be discarded
before the change is made.
If the output baud rate stored in the termios structure
pointed to by the termios_p parameter is the zero baud
rate, B0, the modem control lines will no longer be
asserted. Normally, this will disconnect the line.
If the input baud rate stored in the termios structure
pointed to by the termios_p parameter is 0 (zero), the
input baud rate given to the hardware will be the same as
the output baud rate stored in the termios structure.
Attempts to use the tcsetattr() function from a process
which is a member of a background process group on a
filedes associated with its controlling terminal causes
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 no
signal is sent.
Upon successful completion, 0 (zero) is returned. Otherwise,
-1 is returned and errno is set to indicate the
The tcsetattr() function sets errno to the specified values
for the following conditions:
The filedes parameter is not a valid file descriptor. A
signal interrupted tcsetattr(). The optional_actions
parameter is not a proper value, or an attempt was made to
change an attribute represented in the termios structure
to an unsupported value. The file associated with the
filedes parameter is not a terminal.
Functions: cfgetispeed(3) tcgetattr(3)
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