> For the complete documentation index, see [llms.txt](https://guide.cronuszen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guide.cronuszen.com/gpcscripting/gpc-script-guide/learn-gpc/sizeof-and-addr.md).

# sizeof and addr

`sizeof(CONST_OR_ARRAY)` is evaluated at compile time and returns the declared element/row size understood by the compiler. It is useful for bounded loops:

{% code title="sizeof-bounded-loop.gpc" %}

```cpp
const uint8 BUTTONS[] = { PS5_CROSS, PS5_CIRCLE, PS5_SQUARE };
int i;

main {
    for(i = 0; i < sizeof(BUTTONS); i++) {
        if(get_ival(BUTTONS[i])) {
            set_val(TRACE_1, i);
        }
    }
}
```

{% endcode %}

Zen Studio Live also accepts supported type keywords in `sizeof(type)`. For the fixed-width numeric types, the result is their storage width in bytes:

| Type expression                    | Result |
| ---------------------------------- | -----: |
| `sizeof(int8)` / `sizeof(uint8)`   |    `1` |
| `sizeof(int16)` / `sizeof(uint16)` |    `2` |
| `sizeof(int32)`                    |    `4` |

```cpp
define PROFILE_VALUE_BYTES = sizeof(int16);
define SERIAL_VALUE_BYTES = sizeof(int32);
```

Type support is target-specific. If a keyword has no fixed supported size on the selected target, the compiler reports that `sizeof(keyword)` is not supported.

`addr(CONST_ITEM)` produces a const-data address for APIs that consume strings, images, or adaptive-trigger records. It is not a pointer to a runtime variable and cannot be used on arbitrary expressions.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://guide.cronuszen.com/gpcscripting/gpc-script-guide/learn-gpc/sizeof-and-addr.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.