Function spl_token::instruction::approve_checked

pub fn approve_checked(
    token_program_id: &Pubkey, 
    source_pubkey: &Pubkey, 
    mint_pubkey: &Pubkey, 
    delegate_pubkey: &Pubkey, 
    owner_pubkey: &Pubkey, 
    signer_pubkeys: &[&Pubkey], 
    amount: u64, 
    decimals: u8
) -> Result<Instruction, ProgramError>

Creates an ApproveChecked instruction.