How to hide warnings in compilation from external libraries

Question

I have a main.cpp file which only has this code:

#include <iostream>
#include "include/rapi/RApi.h"

using namespace std;

int main() {
    std::cout << "Test\n";
    return 0;
}

When I compile, I want to see warnings from my code, but not from external included files. I have been able to achieve this in the past, but I might be missing something here in the compilation flags, as I keep on seing errors from the included header file, when I don't want to see them.

This is my compile command:

g++ -isystem include -pedantic -Wall -Wextra main.cpp -o main.o

I want to see warnings and errors from main.cpp, but not from files in the include folder.

I have tried -isysteminclude -isysteminclude/rapi, passing the -isystem to the end of the flags, but to no avail.

Am I missing something here?

Answer 1

You need to add -isystem include to your compile line, then ALSO in your code use:

#include "rapi/RApi.h"

(not include/rapi/RApi.h). The -isystem option only applies the "system header" attribute to files that are looked up using that search path. If you put the full path in the #include then GCC looks up the path directly and doesn't use the -isystem path, so the "system header" attribute is not applied.

Regarding using <> vs "", the exact difference in behavior is essentially implementation-defined. There is no need to guess, just look at various SO questions and answers, such as this one.