tcgetattr(3C)                                       tcgetattr(3C)



NAME
     tcgetattr, tcsetattr - Get or set terminal attributes.

SYNOPSIS
     #include <termios.h>

     int tcgetattr (fildes, termiosp)
     int fildes;
     struct termios *termiosp;

     int tcsetattr (fildes, optionalactions, termiosp)
     int fildes;
     int optionalactions;
     struct termios *termiosp;

DESCRIPTION
     The tcgetattr() and tcsetattr() functions are defined in the
     POSIX 1003.1 standard and used in the OCS and BCS standards.
     CX/UX applications which are not POSIX/OCS/BCS compliant can
     use these functions.

     tcgetattr gets the attributes associated with the terminal
     device referenced by fildes. These attributes are returned
     to the user via the termios structure pointed to by
     termios_p. A background process may call this function, but
     the attributes may be changed by a subsequent foreground
     process call to tcsetattr.

     Tcsetattr sets the attributes associated with the terminal
     device referenced by fildes. These attributes are passed
     into the system via the user modified termios structure
     pointed to by termios_p. The methods of performing this
     action are described by one of the optional_actions as fol-
     lows:

          TCSANOW
               The change shall occur immediately.

          TCSADRAIN
               The change shall occur after all output written to
               fildes has been transmitted (drained).  This
               option should be used when changing parameters
               that affect output (e.g., Preventing output from
               disappearing at low baud rates).

          TCSAFLUSH
               The change shall occur after 1) all output written
               to fildes has been transmitted (drained), and 2)
               all input that has been received but not read has
               been discarded (flushed).

     The optional_actions constants are defined in <termios.h>.



Page 1                        CX/UX Programmer's Reference Manual

tcgetattr(3C)                                       tcgetattr(3C)



     Background processes may not call tcsetattr.  Attempts to do
     so will result in a SIGTTOU signal being sent to the calling
     process and all members of its process group.  The SIGTTOU
     signal will stop the calling process and all members of its
     process group unless the calling process is blocking or
     ignoring this signal.

NOTES
     CX/UX does not support separate line rates for terminal dev-
     ices.  As a result, all references to input rates actually
     refer to output rates.  Therefore, the input rate should be
     specified by the same value as the output rate when using
     tcsetattr.  It is best to use cfsetispeed(3C) with its argu-
     ment speed set to B0 allowing the input rate to be automati-
     cally specified by the value of the output baud rate.  This
     assumes that cfsetospeed(3C) has been previously called.  If
     both input and output baud rates do not match, the tcsetattr
     function call will fail with errno set to [EINVAL].

SEE ALSO
     cfsetispeed(3C), cfgetispeed(3C), cfsetospeed(3C),
     cfgetospeed(3C), termios(7)

DIAGNOSTICS
     Upon successful completion, a value of zero is returned by
     both functions.  If not, a value of -1 is returned and errno
     is set.

     Errno is set to one of the following values for tcgetattr:

     [EBADF]        Fildes is not a valid open file descriptor.

     [ENOTTY]       Fildes is not associated with a terminal dev-
                    ice.

     Errno is set to one of the following values for tcsetattr:

     [EBADF]        Fildes is not a valid open file descriptor.

     [EINVAL]       The optional_actions argument is not a proper
                    value as defined in <termios.h>, or an
                    attempt was made to change an attribute
                    represented in the termios structure to an
                    unsupported value (e.g., input baud rate not
                    equivalent to output baud rate).

     [ENOTTY]       Fildes is not associated with a terminal dev-
                    ice.







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