I'm receiving the following error when attempting to compile using emscripten.

src-fceumm/cart.c:451:4: error: implicit declaration of function 'FCEU_PrintError' is invalid in C99
      [-Werror,-Wimplicit-function-declaration]
                        FCEU_PrintError("Error opening Game Genie ROM image!");

It compiles fine using regular gcc on OS X.

When I add void FCEU_PrintError(char *format, ...) to fceu.h it seems to fix the problem but I'm curious why it's not required for regular gcc.

I check on FCEU sites and I know it's able to emulate light guns using the mouse cursor.
I don't know if it's possible but ...could be awesome to have this function in Open Emu, to play great games like Duck Hunt. Maybe also enable the wiimote to work as NES Zapper.
Thanks.

Hey guys,

I am using OpenEMU and just love it. The one thing missing is turbo button support. I believe this has two parts:

1. You need to add turbo button mapping in UI
2. The FCEU core must understand that mapping so that those buttons can be emulated

So I believe the harder task is no. 2, so may be we can begin with that first?

So if anyone can guide me how to do that, I would love to add these support myself. It will be a fun task to do 👍

For many months I've been unable to build OpenEmu and its cores. It hits a snag building the FCEU portion. Within Terminal, the output is

The following build commands failed:
	CompileC /Users/spamguy/src/OpenEmu/DerivedData/Build/Intermediates/FCEU.build/Release/FCEU.build/Objects-normal/x86_64/cheat.o src/cheat.cpp normal x86_64 c++ com.apple.compilers.llvm.clang.1_0.compiler

Within Xcode, the error is a little more clear.

/Users/spamguy/src/OpenEmu/FCEU/src/cheat.cpp:219:30: Ordered comparison between pointer and zero ('char *' and 'int')

I understand its complaint, but this hasn't been addressed on the FCEU repository itself, so the problem must be on my side. What is escalating this from a warning to an error?

I found that adding this line to FCEUGameCore.mm enables up to four players for Micro Mages:

diff --git a/FCEUGameCore.mm b/FCEUGameCore.mm
index 54a8a54..83b8c63 100644
--- a/FCEUGameCore.mm
+++ b/FCEUGameCore.mm
@@ -185,7 +185,8 @@ static __weak FCEUGameCore *_current;
                                 @"90d2e9f0", // K.Y.F.F. (Homebrew) http://slydogstudios.org/index.php/k-y-f-f/
                                 @"1394ded0", // Super PakPak (Homebrew) http://wiki.nesdev.com/w/index.php/Super_PakPak
                                 @"73298c87", // Super Mario Bros. + Tetris + Nintendo World Cup (Europe)
-                                @"f46ef39a"  // Super Mario Bros. + Tetris + Nintendo World Cup (Europe) (Rev A)
+                                @"f46ef39a", // Super Mario Bros. + Tetris + Nintendo World Cup (Europe) (Rev A)
+                                @"4e6b9078"  // Micro Mages (USA) (Unl) (Homebrew) http://morphcat.de/micromages/
                                 ];
 
     // Most 3-4 player Famicom games need to set '4 player mode' in the expansion port

I didn't find any upstream for FCEU-Core that contains FECUGameCore.mm, so I think this is the right place for this.

What version of zlib is preferred for FCEU-Core? I've tried 1.2.8 and it seems too new. Compiling throws the following errors:

src-fceumm/file.c:171:20: error: member reference base type 'void' is not a structure or union
  for(tmp->size=0; gzgetc(tz) != EOF; tmp->size++);
                   ^~~~~~~~~~
./utils/zlib/zlib.h:1682:15: note: expanded from macro 'gzgetc'
          ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
           ~~~^ ~~~~

When you look at gzgetc it doesn't seem to like passing void as an option since 1.2.4.

I'd be happy to submit PR's to support new versions of zlib if that would be helpful.

Can someone please add additional mappers support? Here is a Windows source with all the new mappers http://sourceforge.net/p/fceumm/code/commit_browser. I was trying to compile it myself but I'm not skilled enough to do this, please help!

I've been using OpenEMU since I purchased my Mac three years ago. Cheat codes work fine for all systems that utilize them, with the exception of any and all AR/FCE Ultra Debug NES codes (format XXXX:YY). They have never worked, and FCEU is the default core on my setup.

MacOS: Mojave 10.14.1
OpenEMU version: 2.0.8 (installed today, 12/4/2018)

Thanks.