String not storing in a structure properly

Question

typedef struct class {
   char* CLASS_ID;
   char* CLASS_NAME;
}

What would cause those two strings to lose their values over the course of 30-40 unrelated lines of code? (Assigned to a pointer returned from a function called getString()).

Answer 1

Perhaps getString() returns a pointer to a statically allocated buffer, whose value is overwritten each time it is called?

Maybe you're overflowing an array and corrupting your stack or heap?

Maybe you're storing a pointer to a string that was allocated on the stack and has gone out of scope?

With some more information about or code for getString(), someone could probably give you a definitive answer.

Answer 2

Well, not knowing how getString() is implemented, or any of your other code, it could be anything. That is part of the problem with C's (over)use of pointers.

My first guess would be that getString() actually returns a pointer to an internal ( static ) string, and thus each call obliterates the value retrieved from the last.

If you are actually using C++, then I would strongly advise you to ditch this code and use std::string instead. I bet your problem magically goes away.

Answer 3

除了此处发布的其他内容之外，还应避免使用class ， CLASS_ID和CLASS_NAME class名称，因为它们在将来可能包含的许多库中是#defined ，并且需要调试数小时才能找出突然出现的问题。