Undefined reference to what does it mean

Please give a try in a clean SDK directory with the. Then, import your own files. Please also take some screenshots with the steps you are following and share them with me.

I have deleted the. But, the errors remain the same. One of the most common errors in compilation happens during the linking stage. The error looks similar to this:. We see here a declaration of foo int foo ; but no definition of it actual function. So we provided the compiler with the function header, but there was no such function defined anywhere, so the compilation stage passes but the linker exits with an Undefined reference error.

For example, if the code above we had provided a definition of foo that looked like this:. To avoid this problem, take some care when writing declarations and definitions, and remember that things like references, pointers and const all count towards making a function signature unique. In this situation, you need to compile both the the source files on the same command line, for example, using GCC:. To understand this issue, remember that a header file. The linker neither knows nor cares about header files — it cares about.

So if you get a linker error regarding a name that is in a library you are using, it is almost certainly because you have not linked with that library. To perform the linkage, if you are using an IDE you can normally simply add the library to your project, if using the command line, once again please see my series of blog articles on the GCC command line starting here , which describes some other linker issues you may have.

The unresolved reference error can have many causes, far from all of which have been described here. You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account. You are commenting using your Facebook account.

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