1、B:\OBJ\HZ.axf: Error: L6915E: Library reports error: __use_no_semihosting was requested, but _sys_open was referenced
解决 办法：勾选“Use Micro LIB”；
2、*** WARNING L16: UNCALLED SEGMENT, IGNORED FOR OVERLAY PROCESS
解决 办法：写了子函数没有调用就会出现这样的警告；
3、WARNING L15: MULTIPLE CALL TO SEGMENT
解决 办法：http://www.cnblogs.com/CuriosityWzk/archive/2011/12/25/2301090.html
Keil4.70A stm32f103ZET6 RA8875调试过程错误处理,布布扣,bubuko.com
Keil4.70A stm32f103ZET6 RA8875调试过程错误处理
原文：http://blog.csdn.net/lhf_2090/article/details/23656871