Including constants without functions

Question

I am making a c++ library and I want to include fcntl.h in the header (for the permission constants)

But I have a function called open, the argument list contains classes that can be casted to the fcntl's open argument list types.

That means when i use #include<fcntl.h> I am getting an ambiguous error.

I want the library to be as portable as possible.

I thought of changing the name from open to Open but is there a better solution?

Like including the header without parsing the functions(eg. Just including the constants).

Answer 1

is there a better solution?

Use a namespace:

namespace my_lib {
  int open(const char *pathname, int flags);
}

And to be clear, a library should always declare its functions/classes/constants/etc... in a namespace, not just as a means to fix a specific issue. This way, you avoid potential conflicts with other libraries that users might be including that you have no visibility on.

Edit: From the followup in the comment, if prefixing things with a namespace gets annoying, you can locally use individual identifiers from a namespace, and that will not be ambiguous, nor will is cause conflicts elsewhere in the code.

#include <fcntl.h>

namespace my_lib {
    int open(const char *pathname, int flags);
}

void foo() {
    using my_lib::open;
    
    open("aaa", 0);
}

You should never resort to using namespace my_lib. However, should you be painted in a corner (e.g. the using namespace is in code you can't change), you can resolve conflicts by explicitly referring to the namespace for the ambiguous symbol.

#include <fcntl.h>

namespace my_lib {
    void bar();
    int open(const char *pathname, int flags);
}

using namespace my_lib;

void foo() {
    bar();

    // use the open() from fcntl.h
    ::open("aaa", 0);

    // Use the open() from my_lib
    ::my_lib::open("aaa", 0);
}