termios.4

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 4 代码 · 共 1,622 行 · 第 1/4 页

.PP
The 
.PN tcgetattr() 
function retrieves the parameters associated with the object
referred to by 
.I fildes 
and store them in the 
.PN termios 
structure referenced by
.I termios_p .
This function is allowed from a background process; however, the
information can be subsequently changed by a foreground process.
.PP
The 
.PN tcsetattr() 
function sets the parameters associated with the terminal
from the 
.PN termios 
structure referenced by 
.I termios_p 
as follows:
.IP \(bu 5
If 
.I optional_actions 
is TCSANOW, the change occurs immediately.
.IP \(bu
If 
.I optional_actions 
is TCSADRAIN, the change occurs after all
output written to 
.I fildes 
has been transmitted.  This function should
be used when changing parameters that affect output.
.IP \(bu
If 
.I optional_actions 
is TCSADFLUSH, the change occurs after all
output written to the object referred to by 
.I fildes 
has been transmitted,
and all input that has been received but not read is discarded
before the change is made.
.PP
.B Returns
.PP
Upon successful completion, a value of zero is returned.  Otherwise, a value
of \-1 is returned and 
.I errno 
is set to indicate the error.
.PP
.B Errors
.PP
If any of the following conditions occur, the 
.PN tcgetattr() 
function returns \-1 and sets 
.I errno 
to the corresponding value:
.IP "\fB[EBADF]\fP" 12
The 
.I fildes 
argument is not a valid file descriptor.
.IP "\fB[EINVAL]\fP"
The device does not support the 
.PN tcgetattr() 
function.
.IP "\fB[ENOTTY]\fP"
The file associated with 
.I fildes 
is not a terminal.
.PP
If any of the following conditions occur, the 
.PN tcsetattr() 
function returns \-1 and sets 
.I errno 
to the corresponding value:
.IP "\fB[EBADF]\fP" 12
The 
.I fildes 
argument is not a valid file descriptor.
.IP "\fB[EINVAL]\fP"
The device does not support the 
.PN tcsetatr() 
function, or the 
.I optional_actions 
argument is not a proper value.
.IP "\fB[ENOTTY]\fP"
The file associated with 
.I fildes 
is not a terminal.
.PP
.B Line Control Functions
.PP
Functions: 
.PN tcsendbreak() , 
.PN tcdrain() , 
.PN tcflush() , 
.PN tcflow()
.PP
.B Syntax
.EX
#include <termios.h>

int tcsendbreak (fildes, duration)
int fildes;
int duration;

int tcdrain (fildes)
int fildes;

int tcflush (fildes, queue_selector)
int fildes;
int queue_selector;

int tcflow (fildes, action)
int fildes;
int action;
.EE
.B Description
.PP
The 
.PN tcsendbreak() 
function sends a ``break'' that is a 
continuous stream of zero-valued bits for a specific duration.  If duration
is zero, it sends zero-valued bits for 0.25 seconds.  If duration is
greater than zero, it sends zero-valued bits for duration*0.1 seconds.
If the object referred to by 
.I fildes 
.is not an asynchronous serial connection,
no break sequence is generated.
.PP
The 
.PN tcdrain() 
function waits until all output written to the object 
referred to by 
.I fildes 
has been transmitted.
.PP
The 
.PN tcflush() 
function discards data written to the object referred to by
.I fildes 
but not transmitted, or data received but not read, depending on the 
value of 
.I queue_selector:
.IP \(bu 5
If 
.I queue_selector 
is TCIFLUSH, it flushes data received but not read.
.IP \(bu 5
If 
.I queue_selector 
is TCOFLUSH, it flushes data written but not
transmitted.
.IP \(bu 5
If 
.I queue_selector 
is TCIOFLUSH, it flushes both data received but not
read, and data written but not transmitted.
.PP
The 
.PN tcflow() 
function suspends transmission or reception of data on the 
object referred to by 
.I fildes , 
depending on the value of 
.I action:
.IP \(bu 5
If 
.I action 
is TCOOFF, it suspends output.
.IP \(bu 5
If 
.I action 
is TCOON, it restarts suspended output.
.IP \(bu 5
If 
.I action 
is TCIOFF, the system transmits a STOP character, which is
intended to cause the terminal device to stop transmitting data to the
system.
.IP \(bu 5
If 
.I action 
is TCION, the system transmits a START character, which is
intended to cause the terminal device to resume transmitting data to the
system.
.IP \(bu 5
The default on open of a terminal file is that neither its input nor its
output is suspended.  
.PP
.B Returns
.PP
Upon successful completion, a value of zero is returned.  Otherwise, a value
of \-1 is returned and 
.I errno 
is set to indicate the error.
.PP
.B Errors
.PP
If any of the following conditions occur, the 
.PN tcsendbreak() 
function returns \-1 and sets 
.I errno 
to the corresponding value:
.IP "\fB[EBADF]\fP" 12
The 
.I fildes 
argument is not a valid file descriptor.
.IP "\fB[EINVAL]\fP" 
The device does not support the 
.PN tcsendbreak() 
function.
.IP "\fB[ENOTTY]\fP"
The file associated with 
.I fildes 
is not a terminal.
.PP
If any of the following conditions occur, the 
.PN tcdrain() 
function returns \-1 and sets 
.I errno 
to the corresponding value:
.IP "\fB[EBADF]\fP" 12
The 
.I fildes 
argument is not a valid file descriptor.
.IP "\fB[EINVAL]\fP"
The device does not support the 
.PN tcdrain() 
function.
.IP "\fB[ENOTTY]\fP"
The file associated with 
.I fildes 
is not a terminal.
.IP "\fB[EINTR]\fP"
A signal interrupted the 
.PN tcdrain() 
function.
.PP
If any of the following conditions occur, the 
.PN tcflush() 
function returns \-1 and sets 
.I errno 
to the corresponding value:
.IP "\fB[EBADF]\fP" 12
The 
.I fildes 
argument is not a valid file descriptor.
.IP "\fB[EINVAL]\fP"
The device does not support the 
.PN tcflush() 
function, or the 
.I queue_selector 
argument is not a proper value.
.IP "\fB[ENOTTY]\fP"
The file associated with 
.I fildes 
is not a terminal.
.PP
If any of the following conditions occur, the 
.PN tcflow() 
function returns \-1 and sets 
.I errno 
to the corresponding value:
.IP "\fB[EBADF]\fP" 12
The 
.I fildes 
argument is not a valid file descriptor.
.IP "\fB[EINVAL]\fP"
The device does not support the 
.PN tcflow() 
function, or the
.I action 
argument is not a proper value.
.IP "\fB[ENOTTY]\fP"
The file associated with 
.I fildes 
is not a terminal.
.PP
.B Get Foreground Process Group Id
.PP
Function: 
.PN tcgetpgrp()
.PP
.B Synopsis
.EX 
#include <sys/types.h>
#include <termios.h>

pid_t tcgetpgrp (fildes)
int fildes;
.EE
.B Description
.PP
The 
.PN tcgetpgrp() 
function returns the value of the process group ID of the
foreground process group associated with the terminal.
.PP
The 
.PN tcgetpgrp() 
function is allowed from a background process; however, the
information can be subsequently changed by a foreground process.
.PP
.B Returns
.PP
Upon successful completion, 
.PN tcgetpgrp() 
retuns the process group ID of the
foreground process group associated with the terminal.  Otherwise, a value
of \-1 is returned and 
.I errno 
is set to indicate the error.
.PP
.B Errors
.PP
If any of the following conditions occur, the 
.PN tcgetpgrp() 
function returns \-1 and sets 
.I errno 
to the corresponding value:
.IP "\fB[EBADF]\fP" 12
The 
.I fildes 
argument is not a valid file descriptor.
.IP "\fB[EINVAL]\fP"
This function is not allowed for the device associated with the 
.I fildes 
argument.
.IP "\fB[ENOTTY]\fP"
The calling process does not have a controlling terminal or the file is
not the controlling terminal.
.PP
.B Set Foreground Process Group ID
.PP
Function: 
.PN tcsetpgrp()
.PP
.B Synopsis
.EX
#include <sys/types.h>
#include <termios.h>

int tcsetpgrp (fildes, pgrp_id)
int fildes;
pid_t pgrp_id;
.EE
.PP
.B Description
.PP
If the process has a controlling terminal, the 
.PN tcsetpgrp() 
function sets
the foreground process group ID associated with the terminal to 
.I pgrp_id.
The file associated with 
.I fildes 
must be the controlling terminal of the calling process,  
and the controlling terminal must be currently associated with the session
of the calling process.  The value of 
.I pgrp_id 
must match a process group
ID of a process in the same session as the calling process.
.PP
.B Returns
.PP
Upon successful completion, 
.PN tcsetpgrp() 
returns a value of zero.  Otherwise, a
value of \-1 is returned and 
.I errno 
is set to indicate the error.
.PP
.B Errors
.PP
If any of the following conditions occur, the 
.PN tcsetpgrp()
function returns \-1 and sets 
.I errno 
to the corresponding value:
.IP "\fB[EBADF]\fP" 12
The 
.I fildes 
argument is not a valid file descriptor.
.IP "\fB[EINVAL]\fP"
This function is not allowed for the device associated with the
.I fildes 
argument or the value of 
.I pgrp_id 
argument is less than or
equal to zero, or exceeds {PID_MAX}.
.IP "\fB[ENOTTY]\fP"
The calling process does not have a controlling terminal or the file
is not the controlling terminal, or the controlling terminal is no 
longer associated with the session of the calling process.
.IP "\fB[EPERM]\fP"
The value of the 
.I pgrp_id 
argument does not match the process group ID of a 
process in the same session as the calling process.
.RE
.SH See Also
csh(1), stty(1), tset(1), ioctl(2), sigvec(2), setsid(2), termio(4), getty(8)