32 bit compilation failing on 64 bit Ubuntu 16.04

Question

I have an application that requires the use of glib and a 32 bit library supplied by a third party.

When I compile on 32 bit Ubuntu the application builds and runs successfully. However when I try the same on 64 bit Ubuntu it fails to build because of the following error:

/usr/include/glib-2.0/glib/gtypes.h: In function ‘_GLIB_CHECKED_ADD_U64’:
/usr/include/glib-2.0/glib/gmacros.h:217:53: error: size of array ‘_GStaticAssertCompileTimeAssertion_0’ is negative
#define G_STATIC_ASSERT(expr) typedef char G_PASTE (_GStaticAssertCompileTimeAssertion_, __COUNTER__)[(expr) ? 1 : -1] G_GNUC_UNUSED
                                                 ^
/usr/include/glib-2.0/glib/gmacros.h:214:47: note: in definition of macro ‘G_PASTE_ARGS’
#define G_PASTE_ARGS(identifier1,identifier2) identifier1 ## identifier2
                                           ^
/usr/include/glib-2.0/glib/gmacros.h:217:44: note: in expansion of macro ‘G_PASTE’
#define G_STATIC_ASSERT(expr) typedef char G_PASTE (_GStaticAssertCompileTimeAssertion_, __COUNTER__)[(expr) ? 1 : -1] G_GNUC_UNUSED
                                        ^
/usr/include/glib-2.0/glib/gtypes.h:422:3: note: in expansion of macro ‘G_STATIC_ASSERT’
G_STATIC_ASSERT(sizeof (unsigned long long) == sizeof (guint64));
^

Note: I have gcc-multilib and g++-multilib. I also tried changing the defines inside /usr/lib/x86_64-linux-gnu/glib-2.0/include/glibconfig.h from 8 to 4 with no success. I also tried installing libglib2.0-dev:i686 but pkg config in cmake can not find glib. I am also using the appropriate -m32 flags for C, CXX and LD

Any help with this issue would be greatly appreciated.

Answer 1

No idea why glib wouldn't try to use int64_t instead of duplicating that. Seems silly to me. Maybe they do this on purpose to increase the chance of breaking if you do what you did, and try to compile 32-bit code using a 64-bit glib install.

To compile 32-bit apps, you need 32-bit library object files (.so). They will come with a glibconfig.h that has appropriate typedefs for -m32.

Installing libglib2.0-dev:i686 should be the right approach. I assume you eventually got that sorted out, so the app you're building finds the -I include paths and -L library paths for it.