pSOSystem System Calls - Read

pSOS+ System Calls ev_receive
ev_receive Enables a task to wait for an event condition.
#include
unsigned long ev_receive(
unsigned long events, /* bit-encoded events */
unsigned long flags, /* event processing attributes */
unsigned long timeout, /* timeout delay */
unsigned long *events_r /* events received */
)
Description
Arguments
This service call enables a task to wait for an event condition. The event condition is
a set of user-defined events and an ANY/ALL waiting condition qualifier. Each task
can wait on 32 events, which are bit-encoded in a long word. An ALL condition
occurs when all of the specified events are received. An ANY condition occurs when
one or more of the specified events is received.
If the selected event condition is satisfied by events already pending,
ev_receive() clears those events and returns. Otherwise, ev_receive() can
return immediately with an error, wait until the requisite events have been received,
or wait until a timeout occurs, depending on the flags argument.
If successful, ev_receive() returns the actual events captured by the call in the
location pointed to by events_r.
events Specifies the set of events. An events argument equal to 0 is a
special case, where ev_receive() returns the pending events but
leaves them pending. In this case, the other parameters are ignored.
flags Specifies the event processing attributes. flags is formed by ORing
the following symbolic constants (one from each pair), which are
defined in . For instance, to specify that ev_receive()
blocks until all events are satisfied, you place EV_WAIT and EV_ALL
in flags, using the following syntax:
EV_WAIT | EV_ALL
To specify that ev_receive() blocks until at least one event is
satisfied, you place EV_WAIT and EV_ANY in flags.
pSOSystem System Calls 1-27
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