170 The global variable should be declared extern in a header file included by both source files, and then defined in only one of those source files: common.h

Dec 14, 2024 · This lesson discusses the most common ways to do this. Global constants as internal variables Prior to C++17, the following is the easiest and most common solution: Create a header file …

Jul 23, 2025 · In C++, extern is a keyword that helps in sharing variables, and functions declared in one file to all the other files. In this article, we will learn how we can use the extern keyword to share …

Nov 23, 2025 · Global variables in C++—variables declared outside the scope of any function, class, or namespace—are a double-edged sword. On one hand, they provide convenient access to shared …

Oct 17, 2021 · Hi guys, While developing I like do organize my code into multiple files, according to functionalities. One thing I usually have to do, is access a global variable between those files. I …

Nov 26, 2015 · If you want to use global variable i of file1.c in file2.c, then below are the points to remember: main function shouldn't be there in file2.c now global variable i can be shared with file2.c …

Nov 4, 2025 · Explore effective C++ strategies using the 'extern' keyword for declaring and defining global variables across multiple source files, including handling 'const' variables.

Nov 28, 2025 · If you’ve ever worked on a C++ project with multiple source files, you’ve likely encountered perplexing linker errors or unexpected runtime behavior related to global variables in …