msp430编程的报错

只看该作者 · 2014-11-10 20:07

Warning[Pe940]: missing return statement at end of non-void function "keyscan" H:\C\按键扫描\main.c 32
为什么？？
uchar keyscan(void)
{
  uchar i;
  uchar keyvalue;
  uchar keyvalue1;
  uchar keyvalue2;
  uchar outdata[4]={0x7f,0xbf,0xdf,0xef};

  for(i=0;i<4;i++)
  {
P1OUT=outdata[i];
if(P1IN|0XF0!=0XFF)
   {
   keyvalue1=P1IN&0X0F;
   keyvalue2=P1OUT&0XF0;
   keyvalue=keyvalue1+keyvalue2;
   return keyvalue;
   }
else
   {
   keyvalue=0XFF;
   return keyvalue;

   }
}
}