For a namespace clean function, implement _link, otherwise implement link. The detailed implementation will depend on the file handling functionality available.

A minimal implementation has no file system, so this function must always fail, with an appropriate value set in errno.

#include <errno.h>

#undef errno
extern int  errno;

int
_link (char *old,
       char *new)
{
  errno = EMLINK;
  return -1;                    /* Always fails */

}       /* _link () */