Lesson 4: msg.value passed to payable subfunctions?

[validydy]

At 5h27min, we send ethers to the function receive, that calls the function fund().
Both "receive" and "fund" are payable function.
Is it normal that "fund" is able to read the content of msg.value even if "receive" does not explicitly pass msg.value to "fund"?
Thanks !

[alymurtazamemon]

@validydy This receive function is the special function that should be declared as payable, you read about it on solidity documentation. It executes on calls to the contract with no data ( calldata ), such as calls made via send() or transfer().

We have put the fund function inside receive so in case a user call contract (not fund function) with no data their amount (msg.value) should not be wasted and our fund function can take that amount and do the rest of the stuff.

Hope it clears your query.

[validydy]

@ali-thegilfoyle Thank you for your answer.
My point was that I was surprised by the fact that we are able to read the content of "msg.value" inside the function fund(), even if "msg.value" is not explicitly sent from function "receive" to function "fund()".
My conclusion is:
the scope of the variable "msg.value" survives beyond only the function receive and that it behaves the same way as msg.sender, which remains readable during the whole transaction.
Can you confirm my understanding?

[alymurtazamemon]

Yes, you are correct msg.value is a global variable, and functions marked as payable can use for receiving from funds.