Minimum example of FSEvent (no thread creation)

fsevent.cpp

#include <CoreServices/CoreServices.h>
#include <iostream>

void callback(
  ConstFSEventStreamRef stream,
  void *callbackInfo,
  size_t numEvents,
  void *evPaths,
  const FSEventStreamEventFlags evFlags[],
  const FSEventStreamEventId evIds[])
{
  char const **paths = (char const**)evPaths;
  for(int i = 0; i < numEvents; ++i) {
    std::cout << (unsigned long long)evIds[i] << "\t" <<
      evFlags[i] << "\t" <<
      paths[i] << "\n"
      ;
  }
}

int main(int argc, char **argv)
{
  CFStringRef arg = CFStringCreateWithCString(
    kCFAllocatorDefault,
    argv[1],
    kCFStringEncodingUTF8);
  CFArrayRef paths = CFArrayCreate(NULL, (const void**)&arg, 1, NULL);
  void *callbackInfo = NULL;
  FSEventStreamRef stream;
  CFAbsoluteTime latency = 3.0;

  stream = FSEventStreamCreate(
    NULL,
    &callback,
    NULL,
    paths,
    kFSEventStreamEventIdSinceNow,
    latency,
    kFSEventStreamCreateFlagNone);

  FSEventStreamScheduleWithRunLoop(stream, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);
  FSEventStreamStart(stream);

  std::cout << "eventID\tFlag\tPath\n";

  CFRunLoopRun();

  FSEventStreamInvalidate(stream);
  FSEventStreamRelease(stream);

  return 0;
}