linux sleep函数跳过输出

Question

执行代码时

DrawBlockWithFeatures(blockY,blockX,nextBlock[0],blockRotate);
getch();

output like this

但执行代码

DrawBlockWithFeatures(blockY,blockX,nextBlock[0],blockRotate)
sleep(2);

There're no blocks with top of the field, shadow, recommends

如何解决？以上两行在线程中执行