base64: Build of 0.5.1 broken with MinGW

@sergeevabc It does work. The reason why it’s throwing an error is because the command adds a newline, which is not part of the base64 alphabet. Try it like this:

$ echo -n Z2l0aHVi | base64.exe -d

The newline thing is a known issue, see #126. I plan to fix it soon by discarding newlines in the input.

@sergeevabc, because the flags changed, be sure to clean out the old build first: make clean.

probably something to do with incorrect use of __declspec(dllexport) and __declspec(dllimport)

Correct, the declaration is marked with dllimport, so it’s expecting to import it from a DLL and decorates the name accordingly, but then it’s statically linked into the same module. This invocation works:

make SSSE3_CFLAGS=1 CFLAGS='-Ilib -O3 -mssse3 -DBASE64_STATIC_DEFINE'

This builds everything as though it were a static library, which is in essence the intention when building the command line program. However, that build command isn’t ideal:

• The -Ilib is necessary because it’s not set properly in the Makefile, nor is there a way to extend it with extras like the -D option. At the top level, Make is a declarative language — resolving all those += before actually building anything — and there isn’t a sense that definitions like CFLAGS are scoped to a particular target or recipe. If you want different flags at different times, use different names and a custom recipe. Example:

  lib/arch/ssse3/codec.o:
      $(CC) -c $(CFLAGS) $(SSSE3_CFLAGS) -o $@ $<
  

  Since -Ilib is so essential, I’d just bake it into the recipe generally, so that CFLAGS can be more freely overridden/extended:

  %.o: %.c
      $(CC) -c -Ilib $(CFLAGS) -o $@ $<
  
  lib/arch/ssse3/codec.o:
      $(CC) -c -Ilib $(CFLAGS) $(SSSE3_CFLAGS) -o $@ $<
  

• SSSE3_CFLAGS similarly doesn’t work as intended per above. It needs to be set to nonempty for lib/config.h, but otherwise it’s not actually used, so I put -mssse3 in CFLAGS as well.

I suspect -DBASE64_STATIC_DEFINE should be in the default CFLAGS for the root Makefile since it exists just to build the command line program.

@sergeevabc Thanks for giving it a try and for posting the full compilation output.

What I think is happening is that the compiler/linker is mangling the names of the functions for some reason. For example, base64_stream_decode_init seems to be renamed internally to __imp_base64_stream_decode_init, and that function is then not found when linking the binary with the library.

My hypothesis: the reason that function is not found is because objcopy is called with this argument: --keep-global-symbols=lib/exports.txt. The file lib/exports.txt contains a hand-curated list of functions that should be exported globally. You can perhaps experiment either by removing that argument to objcopy, or by adding those __imp_* functions to lib/exports.txt by hand.

The real problem is probably something to do with incorrect use of __declspec(dllexport) and __declspec(dllimport). That deserves a closer look, but I think it should be in another ticket.