GPRS_C_SDK: undefined reference to `sin'

1. SDK version（SDK 版本）

{ 2.112 }

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2. In what kind of operation problems appear, and how to reproduce the problem ?（什么样的操作步骤问题会出现，是否是稳定复现，如何复现问题？）

{

when i trying to calc sin/cos/sqrt functions i got this error "undefined reference to `sin’ " i tried to find a solution and add -lm to the makefile flags. any other suggestions ? thanks }

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