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Metered concurrency: Difference between revisions
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m (Changed over to works with template) |
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end Semaphores_Main;
=={{header|D}}==
<d>module socket ;
import std.stdio ;
import std.thread ;
import std.c.time ;
class Semaphore {
private int lockCnt, maxCnt ;
this(int count) { maxCnt = lockCnt = count ;}
void acquire() {
if(lockCnt < 0 || maxCnt <= 0)
throw new Exception("Negative Lock or Zero init. Lock") ;
while(lockCnt == 0)
Thread.getThis.yield ; // let other threads release lock
synchronized lockCnt-- ;
}
void release() {
synchronized
if (lockCnt < maxCnt)
lockCnt++ ;
else
throw new Exception("Release lock before acquire") ;
}
int getCnt() { synchronized return lockCnt ; }
}
class Worker : Thread {
private static int Id = 0 ;
private Semaphore lock ;
private int myId ;
this (Semaphore l) { super() ; lock = l ; myId = Id++ ; }
override int run() {
lock.acquire ;
writefln("Worker %d got a lock(%d left).", myId, lock.getCnt) ;
msleep(2000) ; // wait 2.0 sec
lock.release ;
writefln("Worker %d released a lock(%d left).", myId, lock.getCnt) ;
return 0 ;
}
}
void main() {
Worker[10] crew ;
Semaphore lock = new Semaphore(4) ;
foreach(inout c ; crew)
(c = new Worker(lock)).start ;
foreach(inout c ; crew)
c.wait ;
}</d>
=={{header|E}}==
This semaphore slightly differs from the task description; the release operation is not on the semaphore itself but given out with each acquisition, and cannot be invoked too many times.
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