Linking Error Undefined Reference To
Contents |
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn c++ error undefined reference to function more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users
Undefined Reference To C++ Error
Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping c++ undefined reference to class each other. Join them; it only takes a minute: Sign up Linker Error C++ “undefined reference ” [duplicate] up vote 9 down vote favorite 2 Possible Duplicate: What is an undefined reference/unresolved external symbol error and how do
Linking Error Undefined Reference To Function
I fix it? Trying to compile my program via g++ -o prog1 main.cpp -std=c++0x I get the error: /tmp/cc1pZ8OM.o: In function `main': main.cpp:(.text+0x148): undefined reference to `Hash::insert(int, char)' collect2: error: ld returned 1 exit status main.cpp #include
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
Undefined Reference To Static Variable C++
what the linker is, and what it does. Linker 101 To understand the linker,
Linker Error C++
you have to understand how C++ programs are built. For all but the very simplest programs, the program is composed of multiple c++ linker error unresolved external symbol 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 http://stackoverflow.com/questions/14557657/linker-error-c-undefined-reference 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 https://latedev.wordpress.com/2014/04/22/common-c-error-messages-2-unresolved-reference/ 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 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 fo
files, but I didn't figure out how I can make the main program work. The errors that appear (when I try to compile the source files) are: 1. median.cpp 1
2
[Linker error] undefined http://www.cplusplus.com/forum/beginner/25188/ reference to `WinMain@16' ld returned 1 exit status 2. grade.cpp 1
2
3
[Linker error] undefined reference to `median(std::vector<double, std::allocator<double> >)' [Linker error] undefined reference to `WinMain@16' ld returned 1 exit status 3. student_info.cpp 1
2
[Linker error] undefined reference to `WinMain@16' ld returned 1 exit status 4. 4_data_headers_partitioning.cpp (the main program) 1
2
3
4
[Linker error] undefined reference to `read(std::istream&, Student_info&)' [Linker error] undefined reference to `compare(Student_info const&, Student_info const&)' [Linker error] undefined reference undefined reference to `grade(Student_info const&)' ld returned 1 exit status I attached the source files here: http://www.2shared.com/file/US8dNvZz/partitioning.html Can you help me a little? What I do wrong? Or what I omit? Thanks in advance for your help. (I'm using dev c++ 4.9.9.2 under windows) Jun 19, 2010 at 1:14pm UTC magnificence7 (188) I can't find where to download your files, maybe posting it helps? Anyway, are you sure you've compiled all your source undefined reference to files before linking? Jun 20, 2010 at 1:55am UTC Zhuge (4639) It seems like you are trying to compile all the cpp files as separate programs (hence, looking for WinMain in the other cpps). I don't know how dev c++ works, but there is probably a way to specify a "project" or something that indicates that your files are together a single program. Jun 20, 2010 at 1:56pm UTC Duoas (10453) Yes, start Dev-C++ and create a new Project. Add your main program's cpp file, then add the other cpp files you intend to use in your project. Make sure you create a "Console Application" project -- not a Windows (GUI) application project. Then use Dev-C++ to compile the whole project. Good luck! Jun 24, 2010 at 6:42am UTC adny (10) I added the files into a new project (console application). But again a new error [Build Error] No rule to make target... - I solved that by changing project's path. It seems Dev-C++ has some problem with paths and spaces. I compiled the project (I also compiled every file it contains) and everything was ok, Done. with no errors. But when I run the project, the console appears (the black window with a white cursor :P ) and nothing happens. The project lo