# 收藏一些常用的solidity小机制

**Published by:** [Lucky777](https://paragraph.com/@layflat/)
**Published on:** 2022-05-06
**URL:** https://paragraph.com/@layflat/solidity

## Content

if(balanceOf(uniswapV2Pair) == 0 && to == uniswapV2Pair){ startNumber = block.number; } 这个用来判定加入初始流动性的时间，即上线时间

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