when parent is CCSprite, child setZorder has no use

cocos2d-x C++
#1

I have three ccsprite, for example, spriteParent, spritchild1, spritechild2.
spritechild1 and spritechild2 are child node of spriteparent. when you invoke spritechildX~~>setZOrder, it has no use.
I checked the code, and found in ccsprite.cpp, CCSprite::reorderChild check the zorder is equal to child’s current zorder, which is always true. Because in setZorder, the child’s zorder have been set to new value.
void CCSprite::reorderChild
{
CCAssert;
CCAssert, “”);
* if )*
{
return;
}
if
{
setReorderChildDirtyRecursively;
m_pobBatchNode~~>reorderBatch(true);
}

CCNode::reorderChild(pChild, zOrder);
}