A non-negative real.
A string or
A non-negative fixnum.
It attempts to atomically decrement the semaphore's unit count by count . If this gives a non negative result, then it changes the semaphore's unit count accordingly and returns true. The default value of count is 1.
However, if decrementing the semaphore's unit count would result in a negative number then
waits until the semaphore's unit count is larger than
and tries again. If
is true, then it is used as the thread's
when waiting for the semaphore.
can wait forever. If
is true, it should be an integer. If the semaphore count cannot be decremented within
returns false and the semaphore is unaffected. Pass
0 if you do not want to wait at all.
You can get the current unit count of a semaphore by calling semaphore-count.
LispWorks User Guide and Reference Manual - 21 Dec 2011