Given this source code:
extern const int meaning_of_life __declspec(dllexport); const int meaning_of_life __declspec(dllexport) = 42;
GCC complains:
$ c++ -g -O2 -c test.cxx -o test.o test.cxx:2: error: external linkage required for symbol 'const int meaning_of_life' because of 'dllexport' attribute.
However, it compiles successfully with the "const" qualifier removed:
extern int meaning_of_life __declspec(dllexport); int meaning_of_life __declspec(dllexport) = 42;
Why does adding the "const" qualifier change this? Is this a known limitation of DLLs? If so, the error message is a little confusing. If not, then this is a GCC bug.
Removing the explicit "extern" line has no effect in either case.
My Cygwin installation was updated recently - I'm using the standard Cygwin GCC 3.3.1-3 package:
$ c++ --version c++ (GCC) 3.3.1 (cygming special)
If you want any more info, just ask.
Incidentally, this bug affects src/sid/component/ in the Cygwin CVS tree. I'd prepared this minimal test case before I realized that this subdirectory isn't needed to build the Cygwin DLL. (Doh! CVS doing unexpected things strikes again).
Kind regards,
Jon Foster
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