Parallel task worker in Objective-C

/* taskwork.m: PULLs workload from tcp://localhost:5557
* PUSHes results to tcp://localhost:5558
*/
#import <Foundation/Foundation.h>
#import "ZMQObjC.h"
#define NSEC_PER_MSEC (1000000)

int
main(void)
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
ZMQContext *ctx = [[[ZMQContext alloc] initWithIOThreads:1U] autorelease];

/* (jws/2011-02-05)!!!: Do NOT terminate the endpoint with a final slash.
* If you connect to @"tcp://localhost:5557/", you will get
* Assertion failed: rc == 0 (zmq_connecter.cpp:46)
* instead of a connected socket. Binding works fine, though. */
ZMQSocket *pull = [ctx socketWithType:ZMQ_PULL];
[pull connectToEndpoint:@"tcp://localhost:5557"];

ZMQSocket *push = [ctx socketWithType:ZMQ_PUSH];
[push connectToEndpoint:@"tcp://localhost:5558"];

/* Process tasks forever. */
struct timespec t;
NSData *emptyData = [NSData data];
for (;;) {
NSAutoreleasePool *p = [[NSAutoreleasePool alloc] init];

NSData *d = [pull receiveDataWithFlags:0];
NSString *s = [NSString stringWithUTF8String:[d bytes]];
t.tv_sec = 0;
t.tv_nsec = [s integerValue] * NSEC_PER_MSEC;
printf("%d.", [s intValue]);
fflush(stdout);

/* Do work, then report finished. */
(void)nanosleep(&t, NULL);
[push sendData:emptyData withFlags:0];

[p drain];
}

[ctx closeSockets];
[pool drain];
return EXIT_SUCCESS;
}