pub fn get_return_data() -> Option<(Pubkey, Vec<u8>)>Expand description
Get the return data from an invoked program.
For every transaction there is a single buffer with maximum length
MAX_RETURN_DATA, paired with a Pubkey representing the program ID of
the program that most recently set the return data. Thus the return data is
a global resource and care must be taken to ensure that it represents what
is expected: called programs are free to set or not set the return data; and
the return data may represent values set by programs multiple calls down the
call stack, depending on the circumstances of transaction execution.
Return data is set by the callee with set_return_data.
Return data is cleared before every CPI invocation — a program that
has invoked no other programs can expect the return data to be None; if no
return data was set by the previous CPI invocation, then this function
returns None.
Return data is not cleared after returning from CPI invocations — a program that has called another program may retrieve return data that was not set by the called program, but instead set by a program further down the call stack; or, if a program calls itself recursively, it is possible that the return data was not set by the immediate call to that program, but by a subsequent recursive call to that program. Likewise, an external RPC caller may see return data that was not set by the program it is directly calling, but by a program that program called.
For more about return data see the documentation for the return data proposal.