GP32 [g++ & Sdl] Undefined Reference To `gpmain

[Teal'c]

Greetings,

Well.. I'm having troubles to port a game to gp32.. let me explain:

I'm using GP32 Cross Toolchain for Linux to port a game (C++ and SDL) and i get this error when y try to link all source:

/usr/arm-thumb-elf/lib/libgpos.a(gpos_core.o): In function `GpKernelInitialize':
gpos_core.o(.text+0x2b4): undefined reference to `GpMain'

Do anyone know how i can fix this? Thanks.

 

[Robster]

Errr... maybe add a GpMain() function?

In normal C/C++ programs, the entry point to the program is main(). That's not the case when you're using gamepark's sdk, the entry point for your code must be called "GpMain".

The solution may be as easy as finding the main() function in the source you're compiling, and renaming it to GpMain.

 

[Teal'c]

Nope, i have a GpMain in the code

There's my gpmain.cpp:

#include <gpstdio.h>
#include <gpstdlib.h>
#include <gpgraphic.h>
#include <gpfont.h>

#include "gameplay.h"

void GpMain (void *argv)
{
        GamePlay test;
        test.Loop();
       
}

The class GamePlay uses SDL

I compiled many games with gcc.. but when i try to compile c++ programs with g++ i get that error...

i complied the source by:

arm-thumb-elf-g++ -Iinclude-gp32 -Isrc -Isrc/gb -I/usr/arm-thumb-elf/include/SDL -Iinclude-gp32 -I. -O2 -mtune=arm920 -DGFXST -DGP32 -Wuninitialized -Wno-import -Wchar-subscripts -Wformat -Wimplicit-int -Wimplicit-function-declaration -Wmultichar -Wreturn-type -Wswitch -Wunused -Wuninitialized -Wsign-compare -msoft-float -mthumb-interwork -DYYTEXT_POINTER=1 -DHAVE_LIBPNG=1 -DHAVE_LIBPTHREAD=1 -DHAVE_LIBZ=1 -DSTDC_HEADERS=1 -DHAVE_MALLOC_H=1 -DHAVE_STRINGS_H=1 -DHAVE_UNISTD_H=1 -DHAVE_ARPA_INET_H=1 -DHAVE_NETINET_IN_H=1 -D_REENTRANT -DSDL -DBKPT_SUPPORT -fno-exceptions -DC_CORE -c gpmain.cpp -o gpmain.o

and finally linked all by:

arm-thumb-elf-gcc -o test.elf crt0.o gpstart.o gpmain.o gameplay.o -L/usr/arm-thumb-elf/lib -Tlnkscript user_init.o -nostartfiles -lgpos -lgpsound -lgpmem -lgpgraphic -lgpfont -lSDL -ljpeg -lz -lm -lgpstdlib -lgpstdio -lgpstdlib -lstdc++

 

[Robster]

Aha, then it's probably a C++ name-mangling problem. Because GpMain is in a C++ file, it will be exported by g++ as xyzGpMain#32%!^&* or some such rubbish.

Possibly the solution is just to prototype GpMain as a C function, ie. above the implementation of GpMain, put

extern "C" {
void GpMain (void *argv);
}

Does that work?

 

[Aiken]

I'm using a gpmain.cc too, and no extern "C" used, and it links ok.
Maybe that's not the problem, but try it.

Take a look at gpstart.c, there are some declarations and references to GpMain there, and i have a Main() function there too.

I think the sdk calls Main() and then GpMain() or somethink.

Aiken

 

[DJWillis]

If you link with GCC and compile C++ with G++ then as Rob suggests you will need to extern "C" in order for it to stand a chance of linking and playing nicely.

 

[Teal'c]

Thanks guys, you really help me

extern "C"
{
#include <gpstdio.h>
#include <gpstdlib.h>
#include <gpgraphic.h>
#include <gpfont.h>
}

#include "gameplay.h"

void GpMain (void *argv)
{
       GamePlay test;
       test.Loop();
      
}

Now works fine thanks all!