getattrlist / ATTR_DIR_ENTRYCOUNT

direntrycount.m

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <sys/attr.h>
#include <sys/errno.h>
#include <unistd.h>
#include <sys/vnode.h>

struct DirEntryCount {
    u_int32_t length;
    u_int32_t entryCount;
} __attribute__((aligned(4), packed));

int main(int argc, char **argv) {
  if (argc != 2) {
    fprintf(stderr, "Usage: %s [directory]\n", argv[0]);
    return 1;
  }

  struct attrlist attrList = { .bitmapcount = ATTR_BIT_MAP_COUNT, .dirattr = ATTR_DIR_ENTRYCOUNT };
  struct DirEntryCount dirEntryCount = {0}; 

  int err = getattrlist(argv[1], &attrList, &dirEntryCount, sizeof(dirEntryCount), 0);
  if (err != 0) {
    perror("getattrlist");
    return 2;
  } 

  assert(dirEntryCount.length == sizeof(dirEntryCount)); 
  printf("Directory %s contains %u items\n", argv[1], dirEntryCount.entryCount);
  return 0;
}