Get current working directory of a process in FreeBSD in C using libprocstat [no error handling]

getpwd.c

// cc getpwd.c -l procstat -o getpwd

#include <sys/param.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/un.h>
#include <sys/user.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <libprocstat.h>
#include <sys/sysctl.h>

int
main(int argc, char **argv)
{
  if (argc < 2)
  {
    printf("usage: getpwd PID\n");
    exit(1);
  }
  // to int
  pid_t pid = atoi(argv[1]);
  // Init types
  struct filestat_list *head;
  struct filestat *fst;

  // open sysctl
  struct procstat *procstat = procstat_open_sysctl();

  // get processes
  unsigned int count;
  struct kinfo_proc *procs = procstat_getprocs(procstat, KERN_PROC_PID, pid, &count);

  // get files from process
  head = procstat_getfiles(procstat, &procs[0], 0);
  STAILQ_FOREACH(fst, head, next) {
    if (fst->fs_uflags & PS_FST_UFLAG_CDIR) {
      printf("%s\n", fst->fs_path);
    }
  }

  procstat_close(procstat);
  return 0;
}