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costat |
SYNOPSIS | |
DESCRIPTION | |
RETURN VALUE | |
CAUTION | |
EXAMPLE |
SYNOPSIS |
#include <coproc.h> int costat(coproc_t id);
DESCRIPTION |
The
costat
function returns information about the status of a coprocess.
The
id
argument is the
ID of the coprocess whose status is desired.
RETURN VALUE |
The value returned by
costat
is one of the symbolic constants
STARTING
,
ACTIVE
,
BUSY
,
IDLE
, or
ENDED
. These constants have the
following significance:
STARTING
costart
but
has never been cocalled.
ACTIVE
BUSY
cocall
function. A
BUSY
coprocess cannot be cocalled itself.
IDLE
coreturn
.
The coprocess will not execute again until it is cocalled.
ENDED
CAUTION |
The effects of passing an invalid coprocess
ID to
costat
are unpredictable.
Usually, this causes the value
ENDED
to be returned.
EXAMPLE |
#include <stddef.h> #include <coproc.h> #include <stdlib.h> coproc_t err_proc; /* Cocall the coprocess whose ID is in the variable err_proc. But */ /* abort instead if that coprocess cannot be legally cocalled. */ switch (costat(err_proc)) { case STARTED: case IDLE: cocall(err_proc,NULL); /* Call the error coprocess if */ break; /* this is legal. */ default: abort(); /* Abort if error coprocess not */ } /* available for cocall. */
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