protocol/docs/additional/exceptional_erc20s.md

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Exceptional ERC20s

Some ERC20s have unique behavior that may require extra handling. We document these here as they are discovered.

Assert vs Require

These ERC20's use [assert]{.title-ref} instead of [require]{.title-ref}, which means that if the token reverts then (nearly) all of the gas from your transaction will be consumed. Specifically, you are left with 1/64 of the gas limit. Be mindful of this when implementing fallback logic; for example, if a call to [transferFrom]{.title-ref} reverts then note you will only have 1/64 of the gas limit to handle the exception.

Known tokens:

• KNC
• LINK
• sUSD
• USDT