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sp_io::default_child_storage

Function read

Source 
pub fn read(
    storage_key: <PassFatPointerAndRead<&[u8]> as RIType>::Inner,
    key: <PassFatPointerAndRead<&[u8]> as RIType>::Inner,
    value_out: <PassFatPointerAndReadWrite<&mut [u8]> as RIType>::Inner,
    value_offset: <u32 as RIType>::Inner,
) -> <AllocateAndReturnByCodec<Option<u32>> as RIType>::Inner
Expand description

Allocation efficient variant of get.

Get key from child storage, placing the value into value_out and return the number of bytes that the entry in storage has beyond the offset or None if the storage entry doesn’t exist at all. If value_out length is smaller than the returned length, only value_out length bytes are copied into value_out.