I'm working on calling a third-party DLL from my Perl project using XS, under Cygwin on Windows using g++. One of the DLL functions takes a struct as an argument and returns its main results in a pointer to a struct. For now I pass in a flat list of 28 integers and populate the first struct. Then I call the function. Then I want to flatten the resulting struct into a list of up to 54 integers.
(This seems like a lot of integers, but the DLL function is quite complex and takes a long time to run, so I think it's worth it. Unless someone has a better idea?)
This is close to working. I can tell that the results are mostly sensible. But there are two bizarre problems.
When I print out the same variables, I get different results depending on whether it's in a 'for' loop or not! I show this below. I've stared at this so long now.
I get "Out of memory" as soon as I get to the first XPUSHs.
Here is the XS code.
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "ppport.h"
#include "dll.h"
MODULE = Bridge::Solver::DDS_IF PACKAGE = Bridge::Solver::DDS_IF
PROTOTYPES: ENABLE
void
SolveBoard(inlist)
SV * inlist
INIT:
struct deal dl;
struct futureTricks fut;
int target, solutions, mode, thrId;
int i, j, ret;
if ((! SvROK(inlist)) ||
(SvTYPE(SvRV(inlist)) != SVt_PVAV) ||
av_len((AV *) SvRV(inlist)) != 27)
{
XSRETURN_UNDEF;
}
printf("New INIT OK\n");
PPCODE:
dl.trump = SvIV(*av_fetch((AV *)SvRV(inlist), 0, 0));
dl.first = SvIV(*av_fetch((AV *)SvRV(inlist), 1, 0));
dl.currentTrickSuit[0] = SvIV(*av_fetch((AV *)SvRV(inlist), 2, 0));
dl.currentTrickSuit[1] = SvIV(*av_fetch((AV *)SvRV(inlist), 3, 0));
dl.currentTrickSuit[2] = SvIV(*av_fetch((AV *)SvRV(inlist), 4, 0));
dl.currentTrickRank[0] = SvIV(*av_fetch((AV *)SvRV(inlist), 5, 0));
dl.currentTrickRank[1] = SvIV(*av_fetch((AV *)SvRV(inlist), 6, 0));
dl.currentTrickRank[2] = SvIV(*av_fetch((AV *)SvRV(inlist), 7, 0));
dl.remainCards[0][0] = SvUV(*av_fetch((AV *)SvRV(inlist), 8, 0));
dl.remainCards[0][1] = SvUV(*av_fetch((AV *)SvRV(inlist), 9, 0));
dl.remainCards[0][2] = SvUV(*av_fetch((AV *)SvRV(inlist), 10, 0));
dl.remainCards[0][3] = SvUV(*av_fetch((AV *)SvRV(inlist), 11, 0));
dl.remainCards[1][0] = SvUV(*av_fetch((AV *)SvRV(inlist), 12, 0));
dl.remainCards[1][1] = SvUV(*av_fetch((AV *)SvRV(inlist), 13, 0));
dl.remainCards[1][2] = SvUV(*av_fetch((AV *)SvRV(inlist), 14, 0));
dl.remainCards[1][3] = SvUV(*av_fetch((AV *)SvRV(inlist), 15, 0));
dl.remainCards[2][0] = SvUV(*av_fetch((AV *)SvRV(inlist), 16, 0));
dl.remainCards[2][1] = SvUV(*av_fetch((AV *)SvRV(inlist), 17, 0));
dl.remainCards[2][2] = SvUV(*av_fetch((AV *)SvRV(inlist), 18, 0));
dl.remainCards[2][3] = SvUV(*av_fetch((AV *)SvRV(inlist), 19, 0));
dl.remainCards[3][0] = SvUV(*av_fetch((AV *)SvRV(inlist), 20, 0));
dl.remainCards[3][1] = SvUV(*av_fetch((AV *)SvRV(inlist), 21, 0));
dl.remainCards[3][2] = SvUV(*av_fetch((AV *)SvRV(inlist), 22, 0));
dl.remainCards[3][3] = SvUV(*av_fetch((AV *)SvRV(inlist), 23, 0));
target = SvIV(*av_fetch((AV *)SvRV(inlist), 24, 0));
solutions = SvIV(*av_fetch((AV *)SvRV(inlist), 25, 0));
mode = SvIV(*av_fetch((AV *)SvRV(inlist), 26, 0));
thrId = SvIV(*av_fetch((AV *)SvRV(inlist), 27, 0));
ret = SolveBoard(dl, target, solutions, mode, &fut, thrId);
printf("Return code %d\n", ret);
printf("Nodes %d\n", fut.nodes);
printf("Cards %d\n", fut.cards);
printf("%6s %12s %12s %12s %12s\n",
"", "suit", "rank", "equals", "score");
printf("%6d %12d %12d %12d %12d\n\n",
0, fut.suit[0], fut.rank[0], fut.equals[0], fut.score[0]);
for (i = 0; i < 13; i++)
{
printf("%6d %12d %12d %12d %12d\n",
i, fut.suit[i], fut.rank[i], fut.equals[i], fut.score[i]);
}
printf("\n%6d %12d %12d %12d %12d\n\n",
0, fut.suit[0], fut.rank[0], fut.equals[0], fut.score[0]);
printf("Trying to push nodes\n");
XPUSHs(sv_2mortal(newSViv(fut.nodes)));
printf("Trying to push cards\n");
XPUSHs(sv_2mortal(newSViv(fut.cards)));
printf("Trying to loop\n");
for (i = 0; i <= 12; i++)
{
XPUSHs(sv_2mortal(newSViv(fut.suit [i])));
XPUSHs(sv_2mortal(newSViv(fut.rank [i])));
XPUSHs(sv_2mortal(newSViv(fut.equals[i])));
XPUSHs(sv_2mortal(newSViv(fut.score [i])));
}
printf("Done looping\n");
Here is the relevant part of the DLL header file.
struct futureTricks
{
int nodes;
int cards;
int suit[13];
int rank[13];
int equals[13];
int score[13];
};
struct deal
{
int trump;
int first;
int currentTrickSuit[3];
int currentTrickRank[3];
unsigned int remainCards[4][4];
};
extern "C" int SolveBoard(
struct deal dl,
int target,
int solutions,
int mode,
struct futureTricks *futp,
int threadIndex);
And here is the output. The return code is OK. The nodes and cards are not. If you squint, you might notice that 0 and 768 also occur within the output table, so maybe there's some kind of offset going on.
The first bizarre thing is that the two '0' lines before and after the main table are different from the '0' line in the main table. The data in the main table is as expected, though, including the garbage in lines 10-12.
The second problem is that XPUSHs doesn't do as intended.
New INIT OK
Return code 1
Nodes 0
Cards 768
suit rank equals score
0 0 2 -2147319000 -2147296756
0 2 2 0 2
1 2 6 0 2
2 2 10 768 2
3 2 13 0 2
4 3 14 0 2
5 0 6 0 1
6 0 10 512 1
7 0 13 0 1
8 3 4 0 0
9 3 11 0 0
10 1773292640 -2147056120 4 -2147319000
11 1772354411 0 -2146989552 -2146837752
12 8192 35 2665016 -2147319000
0 0 2 -2147319000 -2147296756
Trying to push nodes
Out of memory!
