# User Instructions

Interact program to program via these instructions, or refer to the GitHub link below:

{% embed url="<https://github.com/solendprotocol/solana-program-library/blob/mainnet/token-lending/program/src/instruction.rs>" %}

**DepositReserveLiquidityAndObligationCollateral** (Supply)

* Deposit reserve liquidity (Transfer) + mint cTokens (MintTo) + Transfer cTokens into CollateralSupplyAddress (Transfer)
* Does not require RefreshReserve as it is impossible to worsen an obligation’s health by repaying.
* [Sample TX](https://solscan.io/tx/3Her2qWoAbits6VuagCmgskfaNiUSCBdr11ZuAV2z74Dcc2uNdT9dBJvXZ4NVUYEPpmGpri5RxPaT7caSQ24X39v)

**WithdrawObligationCollateralAndRedeemReserveCollateral**

* Redeem cTokens from CollateralSupplyAddress
* Exchange cTokens into Tokens using the cToken Rate
* Requires RefreshReserve to ensure that the user is able to withdraw without defaulting their existing borrows
* RefreshReserve → RefreshObligation → WithdrawObligationCollateralAndRedeemReserveCollateral

**BorrowObligationLiquidity**

* Bundled with Refresh Reserve
* if “borrow\_reserve.last\_update.is\_stale(clock.slot)? {” fails, reserve is considered stale (refreshreserve + borrow must be in the same slot)
* RefreshReserve → RefreshObligation → Borrow

**RepayObligationLiquidity**

* Does not require RefreshReserve as it is impossible to worsen an obligation’s health by repaying.

### **cToken Instructions**:

**DepositReserveLiquidity**

* Deposit funds into the reserve, mint cToken
* No need to escrow the cTokens in the CollateralSupplyAddress
* Relies on cToken:Token Ratio

**RedeemReserveCollateral**

* Withdraw Funds, burn cTokens
* Relies on cToken:Token Ratio

### **Monitoring/Misc Instructions**

**RefreshReserve**

* Update the price of every reserve, usually done before RefreshObligation
* Pull Oracle prices
* Update CumulativeBorrowRate to calculate interest paid since last refreshed block
* Update the Obligation CumulativeBorrowRate to apply an increase in borrow value&#x20;
* Update cToken Rate for supply side users
* Done 2x for every reserve, supply and borrow side

**RefreshObligation**

* Done after RefreshReserves
* Calculate individual obligations that ran the Withdraw or Borrow tx to calculate LTV before borrows
* Assess whether the tx can go through based on account health

**Notes**:

RefreshReserve/RefreshObligation used to be required for all transactions, but were removed to reduce oracle reliance after Jan 2022’s network issues.

Liquidator will call RefreshObligation before liquidating&#x20;

However, borrow/withdraw has to check whether the obligation is refreshed in the SAME slot. But obligations require that reserves are refreshed.

RefreshReserve → RefreshObligation (repeated through all the positions) requires a lot of memory, which is limited by Solana, and thus limits our positions to 6.&#x20;