Error when storing pointers in c++ vectors

I'm trying to use c++ vectors to store pointers to a structure like so :

  struct SourceDir {
    int id;
    const unsigned char *alias;
    const unsigned char *description;
    const unsigned char *path;
  };

but then, I cannot retrieve the value, which seems corrupted

      std::vector<SourceDir*> source_dirs;
      while ((step = sqlite3_step(stmt)) != SQLITE_DONE) {
        if (step != SQLITE_ROW) {
          std::cerr << "[ERROR] internal error (SQLite error code" << step << ")\n";
          exit(1);
        }

        struct SourceDir *sourceDir = new SourceDir;
        sourceDir->id = sqlite3_column_int(stmt, 0);
        sourceDir->alias = sqlite3_column_text(stmt, 1);
        sourceDir->path = sqlite3_column_text(stmt, 2);
        sourceDir->description = sqlite3_column_text(stmt, 3);

        source_dirs.push_back(sourceDir);
      }

      for (std::vector<SourceDir*>::iterator it = source_dirs.begin() ; it != source_dirs.end() ; ++it) {
        SourceDir *s = *it;
        std::cerr << s->description << "\n";
      }

it gives random values like so :

@O?V
@O?V

I don't understand what I did wrong