Mar 17, 2017 · You'll need/want to eliminate one (undoubtedly the one in point.c). In a larger program, you typically compile and link separately to avoid re-compiling anything that hasn't changed. You normally specify what needs to be done …

May 2, 2015 · Try compiling it as gcc Main.c Person.c -o MyProgram. Whenever you have multiple files, they all need to be specified when compiling in order to resolve external references, as is the case here. The compiler will spit out object …

Nov 6, 2011 · What is an undefined reference/unresolved external symbol error and how do I fix it?

What is an Undefined Reference Error? Let‘s first demystify what this error actually means. In C, you need to declare a function before using it and define it somewhere. The declaration tells the compiler the function name and signature. The definition contains the actual body and logic.

Feb 5, 2025 · The "undefined reference" error is common in C programming, especially when working with modular code structures involving multiple files. By understanding how to properly declare extern variables and link all components correctly …

Then the fix is to link both the object file from foo.c and undefined_reference.c, or to compile both the source files: $ gcc -c undefined_reference.c $ gcc -c foo.c $ gcc -o working_program undefined_reference.o foo.o $

Apr 25, 2025 · Undefined reference to main is an error message that indicates that the linker is unable to find a definition for the “main” function during the process of compiling your C or C++ program. This article will explain five factors that can prevent the linker from finding the “main” function in your code and how you can correct the error.

Mar 12, 2025 · Struggling with undefined reference/unresolved external symbol errors? Discover their causes and step-by-step fixes to debug your C/C++.

Explains c program undefined reference error and how to resolve the issue using -lm option with c compiler.

Apr 10, 2019 · I'm trying to compile a C program linking two previously created object files but keep getting an 'undefined reference' error. I'm using Visual Code to write the code and Ubuntu on Windows to compile using a makefile.