TRYLOCK(D3)TRYLOCK(D3)NAMETRYLOCK - try to acquire a basic lock
SYNOPSIS
#include <sys/types.h>
#include <sys/ksynch.h>
#include <sys/ddi.h>
int TRYLOCK(lock_t *lockp, pl_t pl);
Arguments
lockp Pointer to the basic lock to be acquired.
pl The interrupt priority level to be set while the lock is held
by the caller.
DESCRIPTION
If the lock specified by lockp is immediately available (can be acquired
without waiting) TRYLOCK sets the interrupt priority level in accordance
with the value specified by pl and acquires the lock. If the lock is not
immediately available, the function returns without acquiring the lock.
Return Values
If the lock is acquired, TRYLOCK returns the previous interrupt priority
level for use by UNLOCK. If the lock is not acquired the value invpl is
returned.
USAGE
Because some implementations require that interrupts that might attempt
to acquire the lock be blocked on the processor on which the lock is
held, portable drivers must specify a pl value that is sufficient to
block out any interrupt handler that might attempt to acquire this lock.
See the description of the min_pl argument to LOCK_ALLOC(D3) for
additional discussion and a list of the valid values for pl.
TRYLOCK may be used to acquire a lock in a different order from the order
defined by the lock hierarchy.
When called from interrupt level, the pl argument must not specify a
priority level below the level at which the interrupt handler is running.
Level
Base or Interrupt.
Synchronization Constraints
Does not sleep.
Driver-defined basic locks, read/write locks, and sleep locks may be held
across calls to this function.
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TRYLOCK(D3)TRYLOCK(D3)REFERENCESLOCK(D3), LOCK_ALLOC(D3), LOCK_DEALLOC(D3), UNLOCK(D3)
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