Originální popis anglicky:
tcsetattr - set the parameters associated with the terminal
Návod, kniha: POSIX Programmer's Manual
#include <termios.h>
int tcsetattr(int
fildes, int
optional_actions ,
const struct termios *
termios_p);
The
tcsetattr() function shall set the parameters associated with the
terminal referred to by the open file descriptor
fildes (an open file
descriptor associated with a terminal) from the
termios structure
referenced by
termios_p as follows:
- *
- If optional_actions is TCSANOW, the change shall
occur immediately.
- *
- If optional_actions is TCSADRAIN, the change shall
occur after all output written to fildes is transmitted. This
function should be used when changing parameters that affect output.
- *
- If optional_actions is TCSAFLUSH, the change shall
occur after all output written to fildes is transmitted, and all
input so far received but not read shall be discarded before the change is
made.
If the output baud rate stored in the
termios structure pointed to by
termios_p is the zero baud rate, B0, the modem control lines shall no
longer be asserted. Normally, this shall disconnect the line.
If the input baud rate stored in the
termios structure pointed to by
termios_p is 0, the input baud rate given to the hardware is the same
as the output baud rate stored in the
termios structure.
The
tcsetattr() function shall return successfully if it was able to
perform any of the requested actions, even if some of the requested actions
could not be performed. It shall set all the attributes that the
implementation supports as requested and leave all the attributes not
supported by the implementation unchanged. If no part of the request can be
honored, it shall return -1 and set
errno to [EINVAL]. If the input and
output baud rates differ and are a combination that is not supported, neither
baud rate shall be changed. A subsequent call to
tcgetattr() shall
return the actual state of the terminal device (reflecting both the changes
made and not made in the previous
tcsetattr() call). The
tcsetattr() function shall not change the values found in the
termios structure under any circumstances.
The effect of
tcsetattr() is undefined if the value of the
termios
structure pointed to by
termios_p was not derived from the result of a
call to
tcgetattr() on
fildes; an application should modify only
fields and flags defined by this volume of IEEE Std 1003.1-2001
between the call to
tcgetattr() and
tcsetattr(), leaving all
other fields and flags unmodified.
No actions defined by this volume of IEEE Std 1003.1-2001, other
than a call to
tcsetattr() or a close of the last file descriptor in
the system associated with this terminal device, shall cause any of the
terminal attributes defined by this volume of
IEEE Std 1003.1-2001 to change.
If
tcsetattr() is called from a process which is a member of a background
process group on a
fildes associated with its controlling terminal:
- *
- If the calling process is blocking or ignoring SIGTTOU
signals, the operation completes normally and no signal is sent.
- *
- Otherwise, a SIGTTOU signal shall be sent to the process
group.
Upon successful completion, 0 shall be returned. Otherwise, -1 shall be returned
and
errno set to indicate the error.
The
tcsetattr() function shall fail if:
- EBADF
- The fildes argument is not a valid file
descriptor.
- EINTR
- A signal interrupted tcsetattr().
- EINVAL
- The optional_actions argument is not a supported
value, or an attempt was made to change an attribute represented in the
termios structure to an unsupported value.
- ENOTTY
- The file associated with fildes is not a terminal.
The
tcsetattr() function may fail if:
- EIO
- The process group of the writing process is orphaned, and
the writing process is not ignoring or blocking SIGTTOU.
The following sections are informative.
None.
If trying to change baud rates, applications should call
tcsetattr() then
call
tcgetattr() in order to determine what baud rates were actually
selected.
The
tcsetattr() function can be interrupted in the following situations:
- *
- It is interrupted while waiting for output to drain.
- *
- It is called from a process in a background process group
and SIGTTOU is caught.
See also the RATIONALE section in
tcgetattr() .
Using an input baud rate of 0 to set the input rate equal to the output rate may
not necessarily be supported in a future version of this volume of
IEEE Std 1003.1-2001.
cfgetispeed() ,
tcgetattr() , the Base Definitions volume of
IEEE Std 1003.1-2001, Chapter 11, General Terminal Interface,
<termios.h>,
<unistd.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
