编绎有没遇到这问题

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#pragma import(__use_no_semihosting)编译会报错   L6915E: Library reports error: __use_no_semihosting was requested, but _ttywrch was referenced  这是什么原因。把这个#pragma import(__use_no_semihosting)屏蔽掉编译就不会报错了 是什么问题啊

275891381

在原子的映射串口1到printf 那块代码int _sys_exit(int x){x = x;}边加上  int _ttywrch(int ch){ch = ch;}