Link Error Undefined Reference To
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Undefined Reference To Function C++
with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack c++ undefined reference to class Overflow is a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up What is an undefined reference/unresolved external symbol error and how do I linking error undefined reference to function fix it? up vote 712 down vote favorite 317 What are undefined reference/unresolved external symbol errors? What are common causes and how to fix/prevent them? Feel free to edit/add your own. c++ linker-error undefined-reference c++-faq unresolved-external share|improve this question edited Aug 4 '14 at 13:33 Arno Duvenhage 805517 asked Sep 24 '12 at 22:27 Luchian Grigore 167k28295455 3 One thing to consider adding is how to deal with
C++ Undefined Reference To Constructor
"undefined vtable" and "undefined typeinfo" errors in particular (since they are less obvious than undefined functions or variables). –Jeremiah Willcock Jul 16 '13 at 18:25 1 I've been marking this question to be a possible dupe of this one. But after going through all of your (brilliant) answers, I can't see this case covered here. I'm aware it's specific about how an IDE sets up the project type and it's linkage dependencies. But that's a such frequently asked question I think it would be worth covered (maybe just with a link to another appropriate dupe) here. If it is already, and I just didn't spot it, forget about this request/comment. –πάντα ῥεῖ Mar 3 '14 at 21:14 @LuchianGrigore 'feel free to add an answer' I preferred to add the relevant link (IMHO) your primary answer, if you'd like to permit. –πάντα ῥεῖ Mar 3 '14 at 22:36 1 Pretty common mistake is that you define a function as a standalone and forget the class selector (e.g. A::) in your .cpp file: You do this (wrong): void myFunc() { /* do stuff */ } Instead of this (right): void A::myFunc() { /* do stuff */ } –jave.web Mar 11 '15 at 18:
Practice Problems Quizzes Resources Source Code Source Code Snippets C and C++ Tips Finding a Job References Function Reference Syntax Reference Programming FAQ Getting Help Message Board Email About Us Dealing undefined reference to static variable c++ with Compiler Errors - Surviving the Compilation Process By Alex Allain It's your undefined reference to c++ linux first C (or C++) program--it's not that long, and you're about to compile it. You hit compile (or enter the
Linker Error C++
build command) and wait. Your compiler spits out fifty lines of text. You pick out words like "warning and "error". Does that mean it worked? you wonder. You look for the resulting executable. http://stackoverflow.com/questions/12573816/what-is-an-undefined-reference-unresolved-external-symbol-error-and-how-do-i-fix Nothing. Damn, you think, I guess I have to figure out what this all means... The Types of Compilation Errors First, let's distinguish between the types of errors: most compilers will give three types of compile-time alerts: compiler warnings, compiler errors, and linker errors. Although you don't want to ignore them, compiler warnings aren't something severe enough to actually keep your program from compiling. Usually, http://www.cprogramming.com/tutorial/compiler_linker_errors.html compiler warnings are an indication that something might go wrong at runtime. How can the compiler know this at all? You might be making a typical mistake that the compiler knows about. A common example is using the assignment operator ('=') instead of the equality operator ('==') inside an if statement. Your compiler may also warn you about using variables that haven't been initialized and other similar mistakes. Generally, you can set the warning level of your compiler--I like to keep it at its highest level so that my compiler warnings don't turn in to bugs in the running program ('runtime bugs'). Nevertheless, compiler warnings aren't going to stop you from getting your program working (unless you tell your compiler to treat warnings as errors), so they're probably a bit less frustrating than errors. Errors are conditions that prevent the compiler from completing the compilation of your files. Compiler errors are restricted to single source code files and are the result of 'syntax errors'. What this really means is that you've done something that the compiler cannot understand. For instance, the statement "for(;)" isn't correct syntax because a for loop always needs to have
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 http://www.cplusplus.com/forum/beginner/25188/ files) are: 1. median.cpp 1
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[Linker error] undefined reference to `WinMain@16' ld returned 1 exit status 2. grade.cpp 1
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[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
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[Linker error] undefined reference to `WinMain@16' ld returned 1 exit status 4. 4_data_headers_partitioning.cpp (the main program) 1
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[Linker error] undefined reference undefined reference to `read(std::istream&, Student_info&)' [Linker error] undefined reference to `compare(Student_info const&, Student_info const&)' [Linker error] 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 undefined reference to 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 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 proble