A global variable in C/C++ is a variable which can be accessed from any module in your program. int myGlobalVariable; This allocates storage for the data, and tells the compiler that you want to access that storage with the name 'myGlobalVariable'.

Jan 13, 2017 · Global variables in C are useful to make code more readable if a variable is required by multiple methods (rather than passing the variable into each method). However, they are dangerous because all locations have the ability to modify that variable, making it potentially difficult to track down bugs.

Jun 12, 2019 · First examine if you really need a global variable instead using it blatantly without consideration to your software architecture. Let's assuming it passes the test. Depending on usage, Globals can be hard to debug with race conditions and many other "bad things", it's best to approach them from an angle where you're prepared to handle such bad ...

Apr 15, 2016 · which place is better to declare a global variable in c program. Answer: In source(*.c) file. Assume the scenario like, I have declared a variable in a header file. I included this header in two different .c files. After the macro expansion step of compilation, these two files will have the global variable with the same name.

Jun 9, 2010 · How can I create global variables that are shared in C? If I put it in a header file, then the linker complains that the variables are already defined. Is the only way to declare the variable in one of my C files and to manually put in externs at the top of all the other C files that want to use it? That sounds not ideal.

static before a global variable means that this variable is not accessible from outside the compilation module where it is defined. E.g. imagine that you want to access a variable in another module: foo.c int var; // a global variable that can be accessed from another module // static int var; means that var is local to the module only. ...

Jan 6, 2015 · how to access the correct global variable in C? 17. Global variable implementation. 2. Global variables in ...

Apr 15, 2013 · Yes. Any global variable is initialized to the default value of that type. 0 is the default value and is automatically casted to any type. If it is a pointer, 0 becomes NULL. Global variables get their space in the data segment which is zeroed out. It is not compiler specific but defined in the C standard. So it will always print 0.

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 by two ways: a) by declaring with extern keyword in file2.c i.e extern int i;

Mar 30, 2016 · // This goes into the header extern int my_global_int; and the C file should say. int my_global_int; Note: The fact that you can do it does not mean that you should do it. Exposing "raw" global variables from a library is a bad practice, because users of your library can do unexpected things to them.