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1 files changed, 39 insertions, 0 deletions

diff --git a/libcommon/export.hxx b/libcommon/export.hxx
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+#pragma once
+
+// Normally we don't export class templates (but do complete specializations),
+// inline functions, and classes with only inline member functions. Exporting
+// classes that inherit from non-exported/imported bases (e.g., std::string)
+// will end up badly. The only known workarounds are to not inherit or to not
+// export. Also, MinGW GCC doesn't like seeing non-exported functions being
+// used before their inline definition. The workaround is to reorder code. In
+// the end it's all trial and error.
+
+#if defined(LIBCOMMON_STATIC)         // Using static.
+#  define LIBCOMMON_SYMEXPORT
+#elif defined(LIBCOMMON_STATIC_BUILD) // Building static.
+#  define LIBCOMMON_SYMEXPORT
+#elif defined(LIBCOMMON_SHARED)       // Using shared.
+#  ifdef _WIN32
+#    define LIBCOMMON_SYMEXPORT __declspec(dllimport)
+#  else
+#    define LIBCOMMON_SYMEXPORT
+#  endif
+#elif defined(LIBCOMMON_SHARED_BUILD) // Building shared.
+#  ifdef _WIN32
+#    define LIBCOMMON_SYMEXPORT __declspec(dllexport)
+#  else
+#    define LIBCOMMON_SYMEXPORT
+#  endif
+#else
+// If none of the above macros are defined, then we assume we are being used
+// by some third-party build system that cannot/doesn't signal the library
+// type. Note that this fallback works for both static and shared libraries
+// provided the library only exports functions (in other words, no global
+// exported data) and for the shared case the result will be sub-optimal
+// compared to having dllimport. If, however, your library does export data,
+// then you will probably want to replace the fallback with the (commented
+// out) error since it won't work for the shared case.
+//
+#  define LIBCOMMON_SYMEXPORT         // Using static or shared.
+//#  error define LIBCOMMON_STATIC or LIBCOMMON_SHARED preprocessor macro to signal libcommon library type being linked
+#endif