OSF

NAME

tcsetattr − Sets the parameters associated with the terminal

LIBRARY

Standard C Library (libc.a)

SYNOPSIS

#include <termios.h>
int tcsetattr (
int file_des,
int optional_actions,
struct termios ∗termios_p );

PARAMETERS

file_des
Specifies an open file descriptor associated with a terminal.

optional_actions
Specifies the options defining how the parameters will be set.

termios_p
Points to a termios structure containing the terminal parameters. 

DESCRIPTION

The tcsetattr() function sets the parameters associated with the terminal referred to by the open file descriptor 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 file_des 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 file_des 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 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 file_des 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. 

NOTES

AES Support Level: Full use

RETURN VALUES

Upon successful completion, 0 (zero) is returned. Otherwise, −1 is returned and errno is set to indicate the error.

ERRORS

If the tcsetattr() function fails, errno may be set to one of the following values:

[EBADF] The file_des parameter is not a valid file descriptor.

[EINVAL] 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. 

[ENOTTY] The file associated with the file_des parameter is not a terminal.

RELATED INFORMATION

Functions: cfgetispeed(3), tcgetattr(3)