Remove data older than a certain time period from an array

remove_old_data.c

//gcc -static -std=c99 -Wall remove_old_data.c -I./src -L. -lbson -lmongoc -o remove_old_data                                                                                                                                                                                                                                                                                                                     
/* remove_old_data.c */

#include "bson.h"
#include "mongo.h"

int main() {
  bson_buffer bb;

  bson cond;
  bson empty;

  time_t oldStamp = 1331772600;

  bson_buffer_init(&bb);
  bson_buffer *bbPull = bson_append_start_object(&bb, "$pull");
  bson_buffer *bbKey = bson_append_start_object(bbPull, "changes");
  bson_buffer *bbTimestamp = bson_append_start_object(bbKey, "time");
  bson_append_int(bbTimestamp, "$lte", oldStamp);
  bson_append_finish_object(bbTimestamp);
  bson_append_finish_object(bbKey);
  bson_append_finish_object(bbPull);
  bson_from_buffer(&cond, &bb);

  const char * ns = "test.main";
  mongo_connection conn[1];

  mongo_connect( conn , NULL );

  mongo_update(conn, ns, bson_empty(&empty), &cond, MONGO_UPDATE_MULTI);

  mongo_destroy(conn);
  bson_destroy(&cond);
}