TTYDEV
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TTYDEV
Structure for a tty device
Synopsis:
typedef struct ttydev_entry {
iofunc_attr_t attr;
iofunc_mount_t mount;
TTYWAIT *waiting_read;
TTYWAIT *waiting_write;
TTYWAIT *waiting_drain;
int c_cflag;
int c_iflag;
int c_lflag;
int c_oflag;
volatile unsigned flags;
volatile unsigned xflags;
int bcnt;
int fwdcnt;
struct ttydev_entry *timer;
int timeout;
int timeout_reset;
union {
int tmrs;
struct {
char spare_tmr;
char tx_tmr;
char brk_tmr;
char dtr_tmr;
} s;
} un;
pid_t brkpgrp;
pid_t huppid;
cc_t c_cc[NCCS];
unsigned char fifo;
unsigned char fwd;
unsigned char prefix_cnt;
unsigned char oband_data;
int highwater;
int baud;
struct winsize winsize;
TTYBUF obuf;
TTYBUF ibuf;
TTYBUF cbuf;
iofunc_notify_t notify[3];
struct ttydev_entry *extra;
TTYWAIT *waiting_open;
void *reserved2; /* reserved for use by io-char */
int (*io_devctlext)(resmgr_context_t *ctp, io_devctl_t *msg, iofunc_ocb_t *ocb);
char name[TTY_NAME_MAX];
} TTYDEV;
Description:
A character driver shares the TTYDEV structure with the io-char library.
This structure is used to handle devices shared between the driver and io-char.
The members include:
- attr
- A resource manager attribute
- mount
- Related to resource manager information
- waiting_read
- The queue to store blocking clients waiting to read
- waiting_write
- The queue to store blocking clients waiting to write
- waiting_drain
- The queue to store blocking clients waiting to drain.
- c_cflag
- POSIX termios flag describing the hardware control of the terminal
- c_iflag
- POSIX termios flag describing the basic terminal input control
- c_lflag
- POSIX termios flag used to control various terminal functions
- c_oflag
- POSIX termios flag describing the basic terminal output control
- flags
- The following flags are currently defined:
- OHW_PAGED -- the output hardware flow control (set by io-char and used by the driver)
- IHW_PAGED -- input hardware flow control is asserted; the device's highwater mark has been reached and doesn't want to receive any more data. This flag also asserts the RTS line.
- OSW_PAGED -- output software flow control is asserted; the device should not transmit any data (set by io-char and used by the driver)
- ISW_PAGED -- input software flow control is asserted; the device's highwater mark has been reached and doesn't want to receive any more data. This flag also transmits VSTOP.
- EDIT_INSERT -- for edit mode. Insert or overstrike typing mode.
- EDIT_PREFIX -- for edit mode. Look for edit keys which begin with a fixed prefix, e.g. ESC [ ansi" used with POSIX c_cc[VPREFIX].
- OBAND_DATA -- indicates that out-of-band data is available
- LOSES_TX_INTR -- tells the character device library (io-char) that the device sometimes fails to generate TX interrupts. With this knowledge of the hardware's short comings, the io-char library will take extra precautions when transmitting data, by using an internal countdown timer to keep track of the time between TX interrupts. If the timer expires before the next TX interrupt comes in, the io-char library assumes the hardware failed to generate the interrupt and attempts to transmit more data by calling tto(). If there's no more data to be transmitted, the countdown timer isn't reloaded.
- TIMER_ACTIVE -- used by io-char
- TIMER_KEEP -- used by io-char
- NOTTY -- used by PTYs
- NL_INSERT -- used to notify application if a \n was changed to a \r
- ISAPTY -- used by PTYs
- PTY_MASTER_ONLY -- used by PTYs
- LITERAL -- used by io-char
- FIRST_TIME_ALONE -- used by io-char
- xflags
- OSW_PAGED_OVERRIDE -- override OSW_PAGED to allow transmission of controlled characters when in a software flow control suspend state. This flag is set by io-char and is used and cleared by the driver.
- bcnt
- Internal to io-char and used to determine the number of bytes needed to notify a read client.
- fwdcnt
- Internal to io-char and used to determine the number of fwd counts.
- timer
- Used by io-char.
- timeout
- Used by io-char.
- timeout_reset
- Used by io-char.
- tmrs
- One of several available for io-char to use.
- spare_tmr
- Spare used only by io-char for drain.
- tx_tmr
- Enabled by LOSES_TX_INTR. The timer causes tto() to be called to work around some parts that lose transmit interrupts.
- brk_tmr
- Used only by io-char sending break; calls tto() (TTO_CTRL, dtrchg).
- dtr_tmr
- Used by io-char to set dtr line i.e. generate SIGHUP calls tto() (TTO_CTRL, dtrchg).
- brkpgrp
- Used by io-char.
- huppid
- Used by io-char.
- c_cc
- POSIX special control-characters.
- fifo
- Used only by the driver.
- fwd
- Forward character used by io-char. It's used with fwdcnt to implement forward, described in readcond().
- prefix_cnt
- For io-char only.
- oband_data
- Out-of-band data set by the driver in <intr.c>. The application gets it from io-char via a devctl().
- highwater
- Set by the driver and used by io-char to determine when to invoke flow control. (Make sure this value is LESS than the input buffer size).
- baud
- The device's baud rate.
- winsize
- Used only by io-char.
- obuf
- The output buffer.
- ibuf
- The input buffer.
- cbuf
- The canonical buffer.
- notify
- The notify list. It implements iofunc_notify_trigger() resource manager
information. The following arguments are used:
- notify[0] -- notify for input used by io-char
- notify[1] -- notify for output to the driver, <tto.c>
- notify[2] -- notify for data that out-of=band to the driver, <intr.c>
- extra
- Used for PTYs.
- waiting_open
- The queue to store blocking clients waiting to open.
- io_devctlext
- Custom devctl command.
- name
- The device's name i.e. /dev/ser1
Classification:
QNX Neutrino
See also:
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