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

# Context Management

> Functions for creating and managing Dear ImGui contexts

Context management functions allow you to create, destroy, and switch between multiple Dear ImGui contexts. Each context maintains its own state, including font atlas, style, and window data.

<Note>
  Each context creates its own `ImFontAtlas` by default. You can share a font atlas between contexts by passing it to `CreateContext()`.
</Note>

## CreateContext

Creates a new Dear ImGui context.

```cpp theme={null}
ImGuiContext* CreateContext(ImFontAtlas* shared_font_atlas = NULL);
```

### Parameters

<ParamField path="shared_font_atlas" type="ImFontAtlas*" default="NULL">
  Optional font atlas to share between contexts. If NULL, a new font atlas will be created.
</ParamField>

### Returns

<ResponseField name="return" type="ImGuiContext*">
  Pointer to the newly created context.
</ResponseField>

### Example

```cpp theme={null}
// Create a context with its own font atlas
ImGuiContext* ctx1 = ImGui::CreateContext();

// Create a context that shares the font atlas
ImFontAtlas* shared_atlas = new ImFontAtlas();
ImGuiContext* ctx2 = ImGui::CreateContext(shared_atlas);
ImGuiContext* ctx3 = ImGui::CreateContext(shared_atlas);
```

<Warning>
  For DLL users: heaps and globals are not shared across DLL boundaries. You must call `SetCurrentContext()` + `SetAllocatorFunctions()` for each static/DLL boundary.
</Warning>

## DestroyContext

Destroys a Dear ImGui context and frees all associated resources.

```cpp theme={null}
void DestroyContext(ImGuiContext* ctx = NULL);
```

### Parameters

<ParamField path="ctx" type="ImGuiContext*" default="NULL">
  The context to destroy. If NULL, destroys the current context.
</ParamField>

### Example

```cpp theme={null}
// Destroy a specific context
ImGuiContext* ctx = ImGui::CreateContext();
ImGui::DestroyContext(ctx);

// Destroy the current context
ImGui::DestroyContext();
```

<Note>
  Always destroy contexts before application shutdown to prevent memory leaks.
</Note>

## GetCurrentContext

Retrieves the currently active Dear ImGui context.

```cpp theme={null}
ImGuiContext* GetCurrentContext();
```

### Returns

<ResponseField name="return" type="ImGuiContext*">
  Pointer to the current context, or NULL if no context is set.
</ResponseField>

### Example

```cpp theme={null}
ImGuiContext* current = ImGui::GetCurrentContext();
if (current != nullptr) {
    // Context is active
}
```

## SetCurrentContext

Sets the active Dear ImGui context. All subsequent ImGui calls will operate on this context.

```cpp theme={null}
void SetCurrentContext(ImGuiContext* ctx);
```

### Parameters

<ParamField path="ctx" type="ImGuiContext*" required>
  The context to make active.
</ParamField>

### Example

```cpp theme={null}
// Create two contexts for different windows
ImGuiContext* ctx_main = ImGui::CreateContext();
ImGuiContext* ctx_overlay = ImGui::CreateContext();

// Render main window
ImGui::SetCurrentContext(ctx_main);
ImGui::NewFrame();
ImGui::Begin("Main Window");
// ... main window content ...
ImGui::End();
ImGui::Render();

// Render overlay window
ImGui::SetCurrentContext(ctx_overlay);
ImGui::NewFrame();
ImGui::Begin("Overlay");
// ... overlay content ...
ImGui::End();
ImGui::Render();
```

<Warning>
  When switching contexts, make sure to complete the frame (call `Render()` or `EndFrame()`) before switching to avoid state corruption.
</Warning>

## Multi-Context Usage Pattern

```cpp theme={null}
// Initialization
ImFontAtlas* shared_atlas = new ImFontAtlas();
ImGuiContext* ctx1 = ImGui::CreateContext(shared_atlas);
ImGuiContext* ctx2 = ImGui::CreateContext(shared_atlas);

// Per-frame rendering
void RenderFrame() {
    // Render first context
    ImGui::SetCurrentContext(ctx1);
    ImGui::NewFrame();
    ImGui::Begin("Window 1");
    ImGui::Text("First context");
    ImGui::End();
    ImGui::Render();
    ImGui_ImplXXX_RenderDrawData(ImGui::GetDrawData());
    
    // Render second context
    ImGui::SetCurrentContext(ctx2);
    ImGui::NewFrame();
    ImGui::Begin("Window 2");
    ImGui::Text("Second context");
    ImGui::End();
    ImGui::Render();
    ImGui_ImplXXX_RenderDrawData(ImGui::GetDrawData());
}

// Cleanup
ImGui::DestroyContext(ctx1);
ImGui::DestroyContext(ctx2);
delete shared_atlas;
```