returnCharValue is not a valid argument for ffi_call
man ffi_call
void ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void
**avalue);
rvalue must point to storage that is sizeof(long) or larger. For
smaller
return value sizes, the ffi_arg or ffi_sarg integral type must
be used to
hold the return value
Le 31 mars 08 à 17:34, Sherm Pendley a écrit :
On Sat, Mar 1, 2008 at 9:00 AM, Greg Parker <[EMAIL PROTECTED]> wrote:
libffi is smart enough to know about all of the ABI rules. If your
ffi_types
correctly describe the method's parameters, then libffi will
marshal them
properly. (If it doesn't, then that's a libffi bug.)
I don't think libffi does any type promotion.
Indeed not - the sample below prints different results when run on PPC
(including Rosetta) and i386. On PPC, only the promoted version
returns the
correct result. On Intel, both of them do. The question then,
becomes -
should libffi be handling this difference transparently?
sherm--
#include <stdio.h>
#define MACOSX
#include <ffi.h>
char getCharFunction() {
return 5;
}
int main (int argc, const char * argv[]) {
ffi_cif cif_nopromote;
ffi_cif cif_promote;
long returnLongValue;
char returnCharValue;
if (ffi_prep_cif( &cif_nopromote,
FFI_DEFAULT_ABI,
0,
&ffi_type_schar,
NULL
)
!= FFI_OK ) {
printf("%s", "Error creating ffi cif_nopromote\n");
return 1;
}
if (ffi_prep_cif( &cif_promote,
FFI_DEFAULT_ABI,
0,
&ffi_type_slong,
NULL
)
!= FFI_OK ) {
printf("%s", "Error creating ffi cif_promote\n");
return 1;
}
ffi_call(&cif_nopromote,
(void(*)(void))getCharFunction,
&returnCharValue,
NULL
);
printf("Return value from cif_nopromote is %d.\n",
returnCharValue);
ffi_call(&cif_promote,
(void(*)(void))getCharFunction,
&returnLongValue,
NULL
);
printf("Return value from cif_promote is %d.\n", returnLongValue);
return 0;
}
--
Greg Parker [EMAIL PROTECTED] Runtime Wrangler
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