> ## Documentation Index
> Fetch the complete documentation index at: https://devdocs.xbox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Example code for event-based Leaderboards

> XSAPI code samples for XBOX Live event-based Leaderboards, including top results, paging, and centering around a specified rank or player.

This topic provides example code for basic leaderboard display, getting a specified page of results, skipping to a specified player in the leaderboard, and getting the next page of leaderboards.

This topic covers the following:

* [Getting the top of a leaderboard](#gttoal)
* [Getting a leaderboard around a specified rank](#galaasr)
* [Getting a leaderboard around a specified player](#galaasp)
* [Getting the next page of leaderboards](#gtnpol)

<a id="gttoal" />

## Getting the top of a leaderboard

Use [XblLeaderboardGetLeaderboardAsync](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardgetleaderboardasync) to return the leaderboard values for the specified leaderboard, starting from the top of the leaderboard. When querying a leaderboard backed by an event-based User Stat, be sure to set the `queryType` field to `XblLeaderboardQueryType::UserStatBacked`.

### Basic leaderboard display (flat C API)

#### Flat C API

```cpp theme={null}
auto asyncBlock = std::make_unique<XAsyncBlock>();
asyncBlock->queue = queue;
asyncBlock->context = nullptr;
asyncBlock->callback = [](XAsyncBlock* asyncBlock)
{
    std::unique_ptr<XAsyncBlock> asyncBlockPtr{ asyncBlock }; // Take over ownership of XAsyncBlock*.
    size_t resultSize;
    HRESULT hr = XblLeaderboardGetLeaderboardResultSize(asyncBlock, &resultSize);

    if (SUCCEEDED(hr))
    {
        leaderboardBuffer.resize(resultSize);
        XblLeaderboardResult* leaderboard{};

        hr = XblLeaderboardGetLeaderboardResult(asyncBlock, resultSize, leaderboardBuffer.data(), &leaderboard, nullptr);

        if (SUCCEEDED(hr))
        {
            // Use XblLeaderboardResult in result.
            for (auto row = 0u; row < leaderboard->rowsCount; ++row)
            {
                std::stringstream rowText;
                rowText << leaderboard->rows[row].xboxUserId << "\t";

                for (auto column = 0u; column < leaderboard->rows[row].columnValuesCount; ++column)
                {
                    rowText << leaderboard->rows[row].columnValues[column] << "\t";
                }
            }
        }
    }
};

// Instantiate and configure the leaderboard query.
XblLeaderboardQuery leaderboardQuery = {}; 
pal::strcpy(leaderboardQuery.scid, sizeof(leaderboardQuery.scid), scid.c_str()) 
leaderboardQuery.leaderboardName = leaderboardName.c_str(); 
leaderboardQuery.queryType = XblLeaderboardQueryType::UserStatBacked;
// For more leaderboard query options, replace the 4-line code block 
// that precedes this comment as indicated in other examples.

HRESULT hr = XblLeaderboardGetLeaderboardAsync(
    xboxLiveContext,
    leaderboardQuery,
    asyncBlock.get());
if (SUCCEEDED(hr))
{
    // The call succeeded, so release the std::unique_ptr ownership of XAsyncBlock* because the callback will take over ownership.
    // If the call fails, std::unique_ptr will keep ownership and delete XAsyncBlock*.
    asyncBlock.release();
}
```

For more information, see the following:

* [XAsyncBlock](/reference/system/xasync/structs/xasyncblock)
* [XblLeaderboardGetLeaderboardAsync](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardgetleaderboardasync)
* [XblLeaderboardGetLeaderboardResult](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardgetleaderboardresult)
* [XblLeaderboardGetLeaderboardResultSize](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardgetleaderboardresultsize)
* [XblLeaderboardQuery](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardquery)
* [XblLeaderboardResult](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardresult)

<a id="galaasr" />

## Getting a leaderboard around a specified rank

Replace the 4-line code block that instantiates and configures the leaderboard query in the previous Basic leaderboard query (flat C API) example with the following code block to get a specified page of results from a leaderboard query.

### Get a specified page of results (C)

#### Flat C API

```cpp theme={null}
XblLeaderboardQuery leaderboardQuery = {};
pal::strcpy(leaderboardQuery.scid, sizeof(leaderboardQuery.scid), scid.c_str());
leaderboardQuery.leaderboardName = leaderboardName.c_str();
leaderboardQuery.skipResultToRank = 100;
leaderboardQuery.maxItems = 100;
leaderboardQuery.queryType = XblLeaderboardQueryType::UserStatBacked;
```

For more information, see [XblLeaderboardQuery](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardquery).

<a id="galaasp" />

## Getting a leaderboard around a specified player

Replace the 4-line code block that instantiates and configures the leaderboard query in the previous Basic leaderboard query (flat C API) example with the following code block to get a leaderboard around a specified player.

#### Flat C API

```cpp theme={null}
XblLeaderboardQuery leaderboardQuery = {};
pal::strcpy(leaderboardQuery.scid, sizeof(leaderboardQuery.scid), scid.c_str());
leaderboardQuery.leaderboardName = leaderboardName.c_str();
leaderboardQuery.skipToXboxUserId = xboxUserId;
leaderboardQuery.maxItems = 100;
leaderboardQuery.queryType = XblLeaderboardQueryType::UserStatBacked;
```

For more information, see [XblLeaderboardQuery](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardquery).

<a id="gtnpol" />

## Getting the next page of leaderboards

To get the next page of a previous leaderboard result, call [XblLeaderboardResultGetNextAsync](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardresultgetnextasync) as shown in the following example code.

#### Flat C API

```cpp theme={null}
auto asyncBlock = std::make_unique<XAsyncBlock>();
asyncBlock->queue = queue;
asyncBlock->context = nullptr;
asyncBlock->callback = [](XAsyncBlock* asyncBlock)
{
    std::unique_ptr<XAsyncBlock> asyncBlockPtr{ asyncBlock }; // Take over ownership of XAsyncBlock*.
    size_t resultSize;
    HRESULT hr = XblLeaderboardResultGetNextResultSize(asyncBlock, &resultSize);

    if (SUCCEEDED(hr))
    {
        std::vector<char> buffer(resultSize, 0);
        XblLeaderboardResult* result{};

        hr = XblLeaderboardResultGetNextResult(asyncBlock, resultSize, buffer.data(), &result, nullptr);
        // Use result to read the leaderboard results.
    }
};

HRESULT hr = XblLeaderboardResultGetNextAsync(
    xboxLiveContext,
    leaderboardResult,
    maxItems,
    asyncBlock.get());
if (SUCCEEDED(hr))
{
    // The call succeeded, so release the std::unique_ptr ownership of XAsyncBlock* because the callback will take over ownership.
    // If the call fails, std::unique_ptr will keep ownership and delete XAsyncBlock*.
    asyncBlock.release();
}
```

For more information, see the following:

* [XAsyncBlock](/reference/system/xasync/structs/xasyncblock)
* [XblLeaderboardResult](/reference/live/xsapi-c/leaderboard_c/structs/xblleaderboardresult)
* [XblLeaderboardResultGetNextAsync](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardresultgetnextasync)
* [XblLeaderboardResultGetNextResult](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardresultgetnextresult)
* [XblLeaderboardResultGetNextResultSize](/reference/live/xsapi-c/leaderboard_c/functions/xblleaderboardresultgetnextresultsize)


## Related topics

- [Event-based Stats & Leaderboards example code](/services/xbox-services/player-data/stats-leaderboards/event-based/how-to/live-statslb-eb-howto-nav.md)
- [Leaderboards](/build/steam-porting-guide/features/steam-leaderboards.md)
- [Events example code](/services/xbox-services/player-data/stats-leaderboards/event-based/events/how-to/live-events-howto-nav.md)
- [Event-based Stats and Leaderboards](/services/xbox-services/player-data/stats-leaderboards/event-based/live-statslb-eb-nav.md)
- [Event-based achievements example code](/services/xbox-services/player-data/achievements/event-based/how-to/live-achievements-eb-howto-nav.md)