> 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.


---

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