Or the project of my friend, compiled and tells me the error that cannot be parsed when he wrote a function compiled. Oh, is it unable to analyze that "unreesloved" is the error, that is, it can't find the implementation of the function. Tell a friend to implement the function on QQ, find that it is an inline function, telling friends to try the inline, oh, okay. Don't be busy, don't you do it for the scorpion inline? How do people use the inline? Later, I studied research, I found that my friend put the implementation of the Inline function in the CPP file ^ _ ^ Well, I usually not pay close attention, I have to remember it later! If the Inline function is implemented in the CPP, only the function in this CPP file can know it, if this INLINE function is called in other CPP files, the connector will give the "unresolved External" error because it can't find it. This function is dropped, hehe!