realpath throws undefined reference to realpath

Question

Im trying to get the path of text file , when i use the method "realpath" & #include<stdlib.h> ,the compiler gives me an error message :"undefined reference to realpath"

• Some programmer dude: realpath is a POSIX function. That means it's standard in Linux and macOS, but doesn't exist for Windows. So what operating system are you working on?
• Some programmer dude: On Windows perhaps use PathCanonicalize?

Answer 1

realpath doesn't exist on Windows, which isn't fully POSIX compliant.

On Windows you can try to define it this:

#include <stdlib.h>
#define realpath(N,R) _fullpath((R),(N),_MAX_PATH)

I know this works with MinGW-w64, but it should work with MSVC too.

If you're writing portable code you can just put this somewhere at the top to keep your code working for multiple platforms:

#ifdef _WIN32
#include <stdlib.h>
#define realpath(N,R) _fullpath((R),(N),_MAX_PATH)
#endif