On Mon, 29 Apr 2024, Pali Rohár wrote:
So based on these experiments when building library, I can conclude that:X = Y is the same as: Y == X and it means that function named X in the source code is present in the result DLL library under name Y. So `foo = bar` is also renaming of the symbol, and not aliasing. For completeness, what happens when both = and == are used at the same line: $ cat test.def LIBRARY "test.dll" EXPORTS foo = func == bar $ cat test.c void func(void) { } $ i686-w64-mingw32-gcc -shared test.c test.def -o test.dll $ readpe -e test.dll Exported functions Library Name: test.dll Functions Function Ordinal: 1 Address: 0x1410 Name: bar So line "X = Y == Z" has same meaning as "Y == Z" and so same as "Z = X". Such logic does not make sense for me, but whatever. It shows that documentation is incomplete and ambiguous.
As far as I know, they're used in different circumstances. When linking a DLL, you'd use the syntax "X = Y" to export a symbol under a different name. MS link also supports this syntax for this purpose.
When creating an import library with dlltool, the == syntax is used with the purpose of creating an import library with a symbol with one name, pointing at a DLL export with a different name.
I see you only inspected the export table of the linked DLLs in your experiment, but you also should create an import library at the same time (-Wl,--out-implib) and inspect what symbols it provides - which hopefully would link against the export names of the DLL that was created at the same time.
// Martin _______________________________________________ Mingw-w64-public mailing list Mingw-w64-public@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
