https://stackoverflow.com › questions › 5559250

You'll need to specify both files, something like: gcc testpoint.c point.c. ...so that it knows to link the functions from both together. With the code as it's written right now, however, you'll then run into the opposite problem: multiple definitions of main.

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://thelinuxcode.com › undefined-reference-function-c

An undefined reference error occurs when you call a function that is declared but not defined anywhere accessible to the compiler. Since the function body is missing, the compiler raises this error when linking the object files together into an executable.

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

In C++, the undefined reference error typically occurs during the linking phase of compilation. This error indicates that the compiler knows about a function or variable (it has been declared), but it cannot find the actual implementation (definition) during the linking process.

https://riptutorial.com › c › example › 12342 › undefined-reference-errors-when-linking

One of the most common errors in compilation happens during the linking stage. The error looks similar to this: $ gcc undefined_reference.c. /tmp/ccoXhwF0.o: In function `main': undefined_reference.c:(.text+0x15): undefined reference to `foo'. collect2: error: ld returned 1 exit status.

https://askubuntu.com › questions › 977858

Instead, you should use g++ in place of gcc, which links libstdc++ automatically. Ex. given $ cat hello.cpp #include <iostream> int main(void) { std::cout << "Hello world" << std::endl; return 0; }

https://askubuntu.com › questions › 1348199

Adding #include "Helper.h" to your main.cpp makes the declaration of Helper::IsStringNumeric visible to the compiler, but you still need to compile Helper.cpp to object code in order to make the definition of Helper::IsStringNumeric available when you link your main program.

https://askubuntu.com › questions › 194193

The solution is as simple as adding the -l flags at the end: gcc test.c -o test -lssl -lcrypto.

https://www.developpez.net › forums › d2057214 › c-cpp › c › probleme-erreur-undefined-reference...

J'ai un problème d'erreur sur mon programme sur Codeblocks. J'ai essayé de réinstaller Codeblocks mais ça ne marche pas. À la ligne 9, ça me met « undefined reference to 'intervalle' » et ça à chaque fonction. Merci d'avance.

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.