https://stackoverflow.com › questions › 8024440

I get the error: main.o(.text+0x1ed): In function `main': : undefined reference to `avergecolumns'. collect2: ld returned 1 exit status. when I gcc *.o. I'm not quite sure what causes this error. Other posters have explained it as the function is not found or the function is empty.

https://openclassrooms.com › forum › sujet › les-sources-de-l-erreur-undefined-reference-to

Des utilisateurs discutent des causes et des solutions de l'erreur "undefined reference to" qui se produit lors du liage des fichiers objets. L'erreur peut être due à un mélange de C et C++, à une configuration du linker ou à d'autres problèmes.

https://www.geeksforgeeks.org › fix-undefined-reference-error-in-cpp

Learn what causes the undefined reference error in C++ and how to fix it with examples. The error occurs when the compiler knows about a function or variable, but cannot find its implementation during the linking phase.

https://stackoverflow.com › questions › 4130434

Though previous posters covered your particular error, you can get 'Undefined reference' linker errors when attempting to compile C code with g++, if you don't tell the compiler to use C linkage. For example you should do this in your C header files:

https://askubuntu.com › questions › 1348199

g++ fails with an undefined reference to symbol 'dlclose@@GLIBC_2.2.5' even with '-ldl'

https://unix.stackexchange.com › questions › 216836

The libraries being linked to should be specified after there is a reference to them. Thus, you will change the command to: gcc -g -O2 -fopenmp -L/usr/lib -o lenstool_tab e_nfwg.o lenstool_tab.o midpnt.o nrutil.o polint.o qromo.o read_bin.o lenstool_tab.o -lcfitsio -lm. This should fix your problem.

https://www.developpez.net › ... › outils-c-cpp › autres-editeurs › gpp-undefined-reference-to

[Résolu] g++ : undefined reference to ... voila, j'ai implémenté le design pattern "Observable" en C++ sous linux (gcc ou g++). le code se compile bien mais j'ai voulu faire un test, j'ai donc écrit un fichier tel que:

https://www.positioniseverything.net › cpp-undefined-reference

C++ undefined reference linker error often pops up when building large code bases, so you can learn how to track them down quickly and rectify the cause here.

https://visualgdb.com › tutorials › linux › libraries › diagnosing

Instead, GCC will only search a few common places (e.g. /usr/include) and the header search directories specified in your project’s settings. In our example, the png.h file is located in toolchain’s /usr/include/libpng directory and won’t be found initially, producing the following error:

https://stackoverflow.com › questions › 22426574

Running 'gcc -I$HOME/ffmpeg/include program.c -L$HOME/ffmpeg/lib -lavcodec' gives 6 undefined reference errors. Some of the methods are from libavcodec and the others are from libavutil. So I added -lavutil at the end of the command and it compiled.