- Undefined Reference To Winmain@16' Dev C++
- Linker Error Undefined Reference To Winmain@16'
- C++ Linker Error Undefined Reference
- Undefined Reference To Winmain Dev C++
- Undefined Reference To Winmain 16
- C++ Link Error Undefined Reference
- Undefined Reference To C++ Error
GCC C Linker errors: Undefined reference to 'vtable for XXX', Undefined reference to 'ClassName::ClassName'. Jun 28, 2010 Linker error undefined reference to `median(std::vectorallocator )' Linker error undefined reference to `WinMain@16' ld returned 1 exit status 3. Studentinfo.cpp 1. Jan 06, 2012 Neumont University's Jamie King discussing the two types of possible C linker errors and what causes them. C Reference Parameters. Undefined and uninitialized variables (C. I get 'Undefined reference to 'email protected' Under Visual C, you need to link with SDL2main.lib. Under the gcc build environments including Dev-C, you need to link with the output of 'sdl-config -libs', which is usually: -lmingw32 -lSDL2main -lSDL2 -mwindows. Oct 30, 2009 The project is set to be linked to a Windows application, whose entry point looks something like 'int WINAPI WinMain( HINSTANCE, HINSTANCE, LPSTR, int )'; you'll need to change the project setting to link to a 'Windows console application'.
| For some reason, though, the program does not recognize these functions when it compiles. |
That is incorrect. You are not having compilation errors. You are having linker errors.
| As I mentioned in the first paragraph, #include<ni488.h> is included in the program and contains all of these functions. |
No, it does not. If it did, you would not be having those linker errors. It must contain
declarations of those functions. This allows the compiler to ensure that you are using the functions correctly. It effectively leaves a note to the linker saying 'here, please call the actual code that does the actual work for this function'. The linker then goes looking through all the binary objects it has been told to look through, which will be your code and any libraries it has been told to look through. If it cannot find the actual (compiled) code that does the actual work, it comes back with the complaint 'undefined reference'.That is what is happening here. Your code is compiling. You have not told the linker where to find the actual compiled code for these library functions.
Introduction
In this article I’ll be looking at the “undefined reference” error message (or “unresolved external symbol, for Visual C++ users). This is not actually a message from the compiler, but is emitted by the linker, so the first thing to do is to understand what the linker is, and what it does.
Linker 101 Ppm batch vst cracked.
To understand the linker, you have to understand how C++ programs are built. For all but the very simplest programs, the program is composed of multiple C++ source files (also known as “translation units”). These are compiled separately, using the C++ compiler, to produce object code files (files with a .o or a .obj extension) which contain machine code. Each object code file knows nothing about the others, so if you call a function from one object file that exists in another, the compiler cannot provide the address of the called function.
This is where the the linker comes in. Once all the object files have been produced, the linker looks at them and works out what the final addresses of functions in the executable will be. It then patches up the addresses the compiler could not provide. It does the same for any libraries (.a and .lib files) you may be using. And finally it writes the executable file out to disk.
The linker is normally a separate program from the compiler (for example, the GCC linker is called ld) but will normally be called for you when you use your compiler suite’s driver program (so the GCC driver g++ will call ld for you).
Traditionally, linker technology has lagged behind compilers, mostly because it’s generally more fun to build a compiler than to build a linker. And linkers do not necessarily have access to the source code for the object files they are linking. Put together, you get a situation where linker errors, and the reasons for them, can be cryptic in the extreme.
Undefined reference Using auto tune problems.
Put simply, the “undefined reference” error means you have a reference (nothing to do with the C++ reference type) to a name (function, variable, constant etc.) in your program that the linker cannot find a definition for when it looks through all the object files and libraries that make up your project. There are any number of reasons why it can’t find the definition – we’ll look at the commonest ones now.
No Definition
Probably the most common reason for unresolved reference errors is that you simply have not defined the thing you are referencing. This code illustrates the problem:
Undefined Reference To Winmain@16' Dev C++
Here, we have a declaration of the function foo(), which we call in main(), but no definition. So we get the error (slightly edited for clarity):
The way to fix it is to provide the definition:
Wrong Definition
Another common error is to provide a definition that does not match up with declaration (or vice versa). For example, if the code above we had provided a definition of foo() that looked like this:
Linker Error Undefined Reference To Winmain@16'
then we would still get an error from the linker because the signatures (name, plus parameter list types) of the declaration and definition don’t match, so the definition actually defines a completely different function from the one in the declaration. 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.
Didn’t Link Object File
This is another common problem. Suppose you have two C++ source files:
and:
If you compile f1.cpp on its own you get this:
and if you compile f2.cpp on its own, you get this even more frightening one:
In this situation, you need to compile both the the source files on the same command line, for example, using GCC:
or if you have compiled them separately down to object files:
C++ Linker Error Undefined Reference
For further information on compiling and linking multiple files in C++, particularly with GCC, please see my series of three blog articles starting here.
Wrong Project Type
The linker error regarding WinMain above can occur in a number of situations, particularly when you are using a C++ IDE such as CodeBlocks or Visual Studio. These IDEs offer you a number of project types such as “Windows Application” and “Console Application”. If you want to write a program that has a int main() function in it, always make sure that you choose “Console Application”, otherwise the IDE may configure the linker to expect to find a WinMain() function instead.
Undefined Reference To Winmain Dev C++
No Library
Undefined Reference To Winmain 16
To understand this issue, remember that a header file (.h) is not a library. The linker neither knows nor cares about header files – it cares about .a and .lib files. 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.
C++ Link Error Undefined Reference
Conclusion
Undefined Reference To C++ Error
The unresolved reference error can have many causes, far from all of which have been described here. But it’s not magic – like all errors it means that you have done something wrong, in you code and/or your project’s configuration, and you need to take some time to sit down, think logically, and figure out what.