C Binary Literal-CodePudding

I know that Binary Literal in C is standardized from C 14.

However, although I fix the std as c 11, it works well. Because actually, I expected an error. The following is my code which I expected an error.

int main(){
  int a = 0b1010; // an error is expected
  std::cout << a << std::endl;
}

Also, I have compiled and executed the above file with the following command.

g   -std=c  11 -Wall main.cpp -o runfile
./runfile

What is the reason that an expected result does not come out? Is there something that I've got wrong?

CodePudding user response：

Binary literals have been a compiler extension in GCC long before C 14 standardized them. You can compile with -pedantic to warn on extensions and -pedantic-errors to elevate those specific warnings to errors:

<source>:3:11: error: binary constants are a C  14 feature or GCC extension
    3 |   int a = 0b1010; // an error is expected
      |           ^~~~~~