undefined reference to __cxa_allocate_exception

[mk.hapless]

Hi,

I've added a library to /external/.  It uses STL and exceptions.

I'm trying to add a small command line utility to test the library.  When I try to build the module, I get undefined symbols from the library:

error: undefined reference to '__cxa_allocate_exception'

error: undefined reference to '__cxa_throw'

error: undefined reference to '__gxx_personality_v0'

etc.

android.mk is:

include $(CLEAR_VARS)

LOCAL_MODULE := wavsender

LOCAL_MODULE_TAGS := eng

LOCAL_CFLAGS += -fexceptions -D_GNU_SOURCE -D_REENTRANT -DDEFINE_LITTLE_ENDIAN -DDEFINE_TRACE -DPLATFORM_ANDROID

LOCAL_CPPFLAGS += -Wno-non-virtual-dtor 

LOCAL_SRC_FILES += WavSender.cpp

LOCAL_SHARED_LIBRARIES := libc libcutils libnetutils

LOCAL_STATIC_LIBRARIES := libcutils libopenhome

LOCAL_STATIC_LIBRARIES += libopenhome libgtest libgabi++ libstlport_static libstdc++ 

LOCAL_LDLIBS += -lstdc++ 

include external/stlport/libstlport.mk

include $(BUILD_EXECUTABLE)

(sorry for the mess, just trying to get it to work ...)

androidabi-g++ comes out as:

prebuilt/darwin-x86/toolchain/arm-linux-androideabi-4.4.x/bin/arm-linux-androideabi-g++ -nostdlib -Bdynamic -Wl,-T,build/core/armelf.x -Wl,-dynamic-linker,/system/bin/linker -Wl,--gc-sections -Wl,-z,nocopyreloc -o out/target/product/generic/obj/EXECUTABLES/wavsender_intermediates/LINKED/wavsender -Lout/target/product/generic/obj/lib -Wl,-rpath-link=out/target/product/generic/obj/lib -lc -llog -lcutils -lnetutils -lc -lstdc++ -lm  out/target/product/generic/obj/lib/crtbegin_dynamic.o    out/target/product/generic/obj/EXECUTABLES/wavsender_intermediates/ohSongcast/WavSender/WavSender.o              out/target/product/generic/obj/STATIC_LIBRARIES/liblog_intermediates/liblog.a out/target/product/generic/obj/STATIC_LIBRARIES/libcutils_intermediates/libcutils.a out/target/product/generic/obj/STATIC_LIBRARIES/libopenhome_intermediates/libopenhome.a out/target/product/generic/obj/STATIC_LIBRARIES/libopenhome_intermediates/libopenhome.a out/target/product/generic/obj/STATIC_LIBRARIES/libgtest_intermediates/libgtest.a out/target/product/generic/obj/STATIC_LIBRARIES/libgabi++_intermediates/libgabi++.a out/target/product/generic/obj/STATIC_LIBRARIES/libstlport_static_intermediates/libstlport_static.a out/target/product/generic/obj/STATIC_LIBRARIES/libstdc++_intermediates/libstdc++.a   -Wl,-z,noexecstack -Wl,--icf=safe -Wl,--fix-cortex-a8   -Wl,--no-undefined  prebuilt/darwin-x86/toolchain/arm-linux-androideabi-4.4.x/bin/../lib/gcc/arm-linux-androideabi/4.4.3/armv7-a/libgcc.a out/target/product/generic/obj/lib/crtend_android.o

What am I doing wrong?  I can't figure out how to get rid of the undefined symbols ...

thanks for any help

[Ron M]

What libc libraries did you previously try to compile this against?
Did it work with glibc? eglibc? uLibc ... ?

I suspect it has to do with your flags and bionic, but I think it
would be informative to know whether that port of you worked on other
configurations - and which ones.

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[mk.hapless]

libgcc

what I've figured out is, if I link against libstc++.a and libsupc++.a
I can get the link errors to go away.

however, exception handling doesn't work - when an exception is thrown
the program gets a segmentation fault. (runs fine using gnu on a PC)

I've reduced the code down to a simple test case (below). I can get
this built and installed into /system/bin. But instead of the third
printf() coming out I get a segmentation fault.

does anyone know why this is?

thanks

--
#include <stdio.h>
#include <map>

class MyException {
private:
const char* message;
std::map<int,int> table;
public:
MyException (const char *m) {
message = m;
};
const char* getMessage() {
return message;
};
};

class TestException {
public:
static int isok (int i) {
if (i == 0) {
throw new MyException ("value is zero!");
} else if (i < 0) {
return 0;
} else {
return 1;
}
};
};

int main (int argc, char* argv[]) {
try {
printf ("isok(1): %d\n", TestException::isok(1));
printf ("isok(-1): %d\n", TestException::isok(-1));
printf ("isok(0): %d\n", TestException::isok(0));
} catch (MyException *e) {
printf ("exception: %s\n", e->getMessage());
}
return 0;
}

[Jean-Baptiste Queru]

Within the platforn, STL and exception support are tricky and best
avoided (and that's quite an understatement).

JBQ

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--
Jean-Baptiste M. "JBQ" Queru
Software Engineer, Android Open-Source Project, Google.

Questions sent directly to me that have no reason for being private
will likely get ignored or forwarded to a public forum with no further
warning.

[mk.hapless]

yes, I understand this now :)

unfortunately, I've got an existing library with over 4400 std:: calls
and over 1500 throws.

so it's either rewrite all that stuff, or face the trickiness of
getting the existing library to link.

I've found this incantation works for my test program:

include $(CLEAR_VARS)
LOCAL_MODULE := ttest
LOCAL_MODULE_TAGS := eng
LOCAL_CFLAGS := -fexceptions \
-I prebuilt/ndk/android-ndk-r6/sources/cxx-stl/gnu-libstdc++/
include \
-I prebuilt/ndk/android-ndk-r6/sources/cxx-stl/gnu-libstdc++/libs/
armeabi-v7a/include
LOCAL_SRC_FILES := test.cpp
LOCAL_LDFLAGS := \
prebuilt/ndk/android-ndk-r6/sources/cxx-stl/gnu-libstdc++/libs/
armeabi-v7a/libstdc++.a \
prebuilt/darwin-x86/toolchain/arm-linux-androideabi-4.4.x/arm-
linux-androideabi/lib/armv7-a/libsupc++.a
include $(BUILD_EXECUTABLE)

but it's a somewhat hackery and not sure how I'd make it work for any
platform / target combination ...

is there some standard way to pull in those headers and libraries?

[Jean-Baptiste Queru]

There's explicitly no standard way to do that from a platform app,
because it creates some licensing issues that we want to avoid.

JBQ