Function btck_block_spent_outputs_count 

pub unsafe extern "C" fn btck_block_spent_outputs_count(
    block_spent_outputs: *const btck_BlockSpentOutputs,
) -> usize

@brief Returns the number of transaction spent outputs whose data is contained in block spent outputs.

@param[in] block_spent_outputs Non-null. @return The number of transaction spent outputs data in the block spent outputs.