AWAIT EVENT

pawait_event

CALL SEQUENCE

void pawait_event (timeout, ws_id, class, input_dev)

INPUT PARAMETERS

Pfloat	timeout,

OUTPUT PARAMETERS

Pint	*ws_id,
Pin_class	*class,
Pint	*input_dev

ARGUMENTS

timeout,

Time-out (seconds)

ws_id,

workstation identifier

class,

Device class

input_dev

Logical input device number

TYPES

typedef enum {
	PIN_NONE, 
	PIN_LOC, 
	PIN_STROKE, 
	PIN_VAL, 
	PIN_CHOICE, 
	PIN_PICK, 
	PIN_STRING
} Pin_class;

PHIGS STATE

EFFECT

If the input queue is empty, GPHIGS waits until an event takes place or until the timeout expires. If the time-out expires without an event taking place, a NONE value is returned to the input device class. If there is at least one report in the queue, the oldest is removed from the queue and transferred to the PHIGS state list in the current event report. The workstation identifier, the class of input device and input device logical number are returned and the associated values are made available for interrogation by a function of type GET <input class>.

Note:

• 1) Operation takes place even if the event queue is full (error 256).
• 2) A time-out value less than or equal to zero causes the queue to be immediately scanned and a NONE value is returned if the queue is empty.
• 3) Some systems do not provide an efficient time-out function; in this case, a non-zero time-out value can cause an infinite wait.

Example:

/* Get next event into the PHIGS event queue ; return without waiting if queue is empty */
	Pfloat timeout;
	Pint ws_id,input_dev;
	Pin_class class;
	......
	timeout = 0.;
	pawait_event(timeout,&ws_id,&class,&input_dev);
	......

ERRORS

256 Warning, the input queue has overflowed

SEE ALSO