Assuming loginrec.c, it's been refactored to this in 6.5p1:

    if (strlcpy(li->username, pw->pw_name, sizeof(li->username)) >=
        sizeof(li->username)) {
      error("%s: username too long (%lu > max %lu)", __func__,
          (unsigned long)strlen(pw->pw_name),
          (unsigned long)sizeof(li->username) - 1);
      return NULL;
    }