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@vieyang
Created August 11, 2020 07:11
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Send value and data to an unknown address inside the contract
function external_call0(address destination, uint value, uint dataLength, bytes data) internal returns (bool) {
return (destination.call.value(tx.value)(tx.data))
}
function external_call1(address destination, uint value, uint dataLength, bytes data) internal returns (bool) {
bool result;
assembly {
let x := mload(0x40) // "Allocate" memory for output (0x40 is where "free memory" pointer is stored by convention)
let d := add(data, 32) // First 32 bytes are the padded length of data, so exclude that
result := call(
sub(gas, 34710), // 34710 is the value that solidity is currently emitting
// It includes callGas (700) + callVeryLow (3, to pay for SUB) + callValueTransferGas (9000) +
// callNewAccountGas (25000, in case the destination address does not exist and needs creating)
destination,
value,
d,
dataLength, // Size of the input (in bytes) - this is what fixes the padding problem
x,
0 // Output is ignored, therefore the output size is zero
)
}
return result;
}
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vieyang commented Aug 11, 2020

Which is the best way to send value and data to an unknown address inside the contract?

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