libffi and longs

[Pupeno <pupeno at pupeno dot com>]

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Hello,
I've had troubles in the FFI module I'm building when dealing with (unsigned) 
longs, what happens is that the second unsigned long argument never reached 
the function I'm calling with ffi_call.
I've built a small test (attached) to show this particular problem (in the 
hope that the problem would disappear, but that didn't happen). I've checked 
and re-checked how I pass the arguments to ffi_call, I couldn't find anything 
wrong (debugging libffi internals is not easy :( ).
Any hints are helpful.
Thanks.
- -- 
Pupeno: pupeno@pupeno.com - http://pupeno.com
Reading Science Fiction ? http://sfreaders.com.ar
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#include <stdio.h>

unsigned long uLongSum(unsigned long a, unsigned long b){
	printf("Summing unsigned long %ld to unsigned long %ld. Resulting in %ld.\n", a, b, a + b);
	return a + b;
}

signed long sLongSum(signed long a, signed long b){
	printf("Summing signed long %ld to signed long %ld. Resulting in %ld.\n", a, b, a + b);
	return a + b;
}

CC=gcc

all: libffitarget.so testffi

ffitarget.o: ffitarget.c
	$(CC) -fPIC -Wall -g -ggdb -c ffitarget.c

libffitarget.so: ffitarget.o
	gcc -g -ggdb -shared -Wl,-soname,libffitarget.so.0 -o libffitarget.so ffitarget.o -lc 

testffi: testffi.c
	gcc testffi.c -o testffi -ldl -lffi -g -ggdb
clean:
	-rm libffitarget.so ffitarget.o testffi

#include <stdio.h>
#include <ffi.h>
#include <dlfcn.h>

int main(){
	unsigned long a = 150;
	unsigned long b = 345;
	unsigned long rc;
	void *libHandle;
	void *funcHandle;
	void *values[2];
	ffi_type *args[2];
	ffi_cif cif;

	/* Initialize the argument info vectors */
	args[0] = &ffi_type_ulong;
	args[1] = &ffi_type_ulong;
	values[0] = &a;
	values[1] = &b;

	libHandle = dlopen("./libffitarget.so", RTLD_LAZY);
	funcHandle = dlsym(libHandle, "uLongSum");

	/* Initialize the cif */
	if(ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 2, &ffi_type_uint, args) == FFI_OK){
		ffi_call(&cif, funcHandle, &rc, values);
		printf("It returned %ld.\n", rc);
	}

	return 0;
}