> For the complete documentation index, see [llms.txt](https://calnix.gitbook.io/eth-dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://calnix.gitbook.io/eth-dev/compendium/solidity-basics/global-objects.md).

# Global Objects

## Special global variables

along with `msg.sender` there are other `msg` special global variables that are useful:

* `msg.data` — The complete `calldata` which is a non-modifiable, non-persistent area where function arguments are stored and behave mostly like `memory`
* `msg.gas` — Returns the available gas remaining for a current transaction (you can learn more about gas in Ethereum [here](https://www.cryptocompare.com/coins/guides/what-is-the-gas-in-ethereum/))
* `msg.sig` — The first four bytes of the calldata for a function that specifies the function to be called (i.e., function selector)
* `msg.value` — The amount of wei sent with a message to a contract (wei is a denomination of ETH)

<figure><img src="https://1628544884-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTgomzlmn9NrxUY0OQ3cD%2Fuploads%2FROrn51uLpabpvzvUgAFY%2Fimage.png?alt=media&amp;token=04acc4bf-09cc-4304-9d60-cb528d4d55d3" alt=""><figcaption></figcaption></figure>