dll_spec.h

#ifndef DLL_SPEC_H
#define DLL_SPEC_H

#if defined _WIN32 || defined __CYGWIN__

#ifdef BUILDING_DLL
#ifdef __GNUC__
#define DLL_PUBLIC __attribute__((dllexport))
#else
#define DLL_PUBLIC                                                             \
  __declspec(dllexport) // Note: actually gcc seems to also supports this
                        // syntax.
#endif
#else
#ifdef __GNUC__
#define DLL_PUBLIC __attribute__((dllimport))
#else
#define DLL_PUBLIC                                                             \
  __declspec(dllimport) // Note: actually gcc seems to also supports this
                        // syntax.
#endif
#endif
#define DLL_LOCAL

#else

#if __GNUC__ >= 4
#define DLL_PUBLIC __attribute__((visibility("default")))
#define DLL_LOCAL __attribute__((visibility("hidden")))
#else
#define DLL_PUBLIC
#define DLL_LOCAL
#endif

#endif

#endif // DLL_SPEC_H