If there's an undefined reference error, usually it's because the .o file (which gets created from the .cpp file) doesn't exist and your compiler/build system is not able to link it. Also, in your card.cpp, the function should be Card::Card() instead of void Card .
If you get undefined-reference errors such as the following for functions that do not exist on your system, it usually means that your MySQL client library was compiled on a system that is not 100% compatible with yours: mf_format.o(.text+0x201): undefined reference to `__lxstat' Apr 07, 2017 · C++: “undefined reference to” templated class function 1 7 April 2017 in C++ tagged C++ / template / undefined reference to by Tux In case you have a project where you use a templated class that is split in its own header ( .h ) and source ( .cpp ) files, if you compile the class, into an object file ( .o ), separately from the code that When I compile this program with gcc -std=c11 test.c -O2, everything looks great. I have no idea that I have written an undefined C program. Suddenly one day for whatever reason I forget to specify -O2 when compiling, and see an error: undefined reference to 'foo'. What is going on? Jan 03, 2014 · I appreciate that you've said this is a matter of personal preference. I can think of one very solid, pragmatic reason not to do it that way: if your method definitions are in the header file, then every file that includes that header file becomes dependent on the implementation of those methods.
When I compile this program with gcc -std=c11 test.c -O2, everything looks great. I have no idea that I have written an undefined C program. Suddenly one day for whatever reason I forget to specify -O2 when compiling, and see an error: undefined reference to 'foo'. What is going on?
Now this code will compile. An alternative situation arises where the source for foo() is in a separate source file foo.c (and there's a header foo.h to declare foo() that is included in both foo.c and undefined_reference.c). Then the fix is to link both the object file from foo.c and undefined_reference.c, or to compile both the source files: Apr 22, 2014 · f1.cpp:(.text+0xc): undefined reference to `foo()' and if you compile f2.cpp on its own, you get this even more frightening one: crt0_c.c:(.text.startup+0x39): undefined reference to `WinMain@16. In this situation, you need to compile both the the source files on the same command line, for example, using GCC: $ g++ f1.cpp f2.cpp -o myprog
si*****@gmail.com wrote: Hello-I've got a nice C program written that uses libsndfile (#include ) to convert my raw data into a properly-formatted wav file.
Jan 07, 2014 · undefined reference to 'cprintf' undefined reference to 'textcolor' undefined reference to 'clrscr' i use codeblocks 12.11 Mingw also i used all the libraries that i know for the compilation so i think isn't a library problem here's the libraries : Apr 05, 2018 · Also Read – Solved – Undefined reference to ‘pthread_create’ in Linux with Explanation […] Mar 17, 2020 · Hello, I’m a more or less unexperienced user regarding C/C++ and new to PIO (with VS Code, Win 10). In my current project I wanted to reuse some libs, which I successfuly used years ago in a (mainly) non-Arduino environment. What I can’t manage to track down is the cause of this linker error: