Get warning when a variable is shadowed
Both gcc and clang support the -Wshadow
flag which will warn about variables that shadow one another. For example the warning I receive from gcc
for your code is the following:
warning: declaration of ‘n’ shadows a previous local [-Wshadow]
for (int n = 1; n <= 10; n++){
^
warning: shadowed declaration is here [-Wshadow]
int n = 3;
^
gcc
documents the flag here and says:
Warn whenever a local variable or type declaration shadows another variable, parameter, type, class member (in C++), or instance variable (in Objective-C) or whenever a built-in function is shadowed. Note that in C++, the compiler warns if a local variable shadows an explicit typedef, but not if it shadows a struct/class/enum.
In Visual Studio this looks like it was not possible before but seems to be fixed in recent versions.
Related videos on Youtube
Ystar
Updated on September 14, 2022Comments
-
Ystar over 1 year
I generally want to avoid code like this:
#include <stdio.h> int main(int argc, char *argv[]){ int n = 3; for (int n = 1; n <= 10; n++){ printf("%d\n", n); } printf("%d\n", n); }
How can I find such usage of variables? That means, that in the same function a "more local" variable has the same name as a more global variable?
C-Standard : C 99