Hi Andrey,
I made the following changes as suggested by you:
InitStruct := C.calloc(1, C.sizeof_struct_Foo)
InitStruct.key_value_cb = C.callOnMeGo_cgo
InitStruct.data = C.int(1)
C.initialize_engine(pattern_db, module_path,
(*C.Foo)(unsafe.Pointer(InitStruct)))
Still Getting following error:
Am i missing something?
go build -v -x main.go cfuncs.go
WORK=/tmp/go-build822337807
command-line-arguments
mkdir -p $WORK/b001/
cd /home/nsaboo/Documents/goworkspace/src/poc
pkg-config --cflags -- syslog-ng eventlog
pkg-config --libs -- syslog-ng eventlog
CGO_LDFLAGS='"-g" "-O2" "syslog-node.so" "-L/usr/local/lib/" "-lsyslog-ng"
"-L/usr/local/lib/syslog-ng" "-ldbparser" "-L/usr/local/lib"
"-Wl,--export-dynamic" "-lgmodule-2.0" "-pthread" "-lgthread-2.0"
"-pthread" "-lglib-2.0" "-lsyslog-ng" "-lglib-2.0" "-levtlog"'
/usr/local/go/pkg/tool/linux_amd64/cgo -objdir $WORK/b001/ -importpath
command-line-arguments -- -I/usr/local/include/syslog-ng
-I/usr/local/include/syslog-ng/ivykis -I/usr/local/include/eventlog
-I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I
$WORK/b001/ -g -O2 -I/usr/local/include/ ./main.go ./cfuncs.go
cd $WORK
gcc -fno-caret-diagnostics -c -x c - || true
gcc -Qunused-arguments -c -x c - || true
gcc -fdebug-prefix-map=a=b -c -x c - || true
gcc -gno-record-gcc-switches -c -x c - || true
cd $WORK/b001
TERM='dumb' gcc -I /home/nsaboo/Documents/goworkspace/src/poc -fPIC -m64
-pthread -fmessage-length=0 -fdebug-prefix-map=$WORK/b001=/tmp/go-build
-gno-record-gcc-switches -I/usr/local/include/syslog-ng
-I/usr/local/include/syslog-ng/ivykis -I/usr/local/include/eventlog
-I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I ./
-g -O2 -I/usr/local/include/ -o ./_x001.o -c _cgo_export.c
TERM='dumb' gcc -I /home/nsaboo/Documents/goworkspace/src/poc -fPIC -m64
-pthread -fmessage-length=0 -fdebug-prefix-map=$WORK/b001=/tmp/go-build
-gno-record-gcc-switches -I/usr/local/include/syslog-ng
-I/usr/local/include/syslog-ng/ivykis -I/usr/local/include/eventlog
-I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I ./
-g -O2 -I/usr/local/include/ -o ./_x002.o -c main.cgo2.c
TERM='dumb' gcc -I /home/nsaboo/Documents/goworkspace/src/poc -fPIC -m64
-pthread -fmessage-length=0 -fdebug-prefix-map=$WORK/b001=/tmp/go-build
-gno-record-gcc-switches -I/usr/local/include/syslog-ng
-I/usr/local/include/syslog-ng/ivykis -I/usr/local/include/eventlog
-I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I ./
-g -O2 -I/usr/local/include/ -o ./_x003.o -c cfuncs.cgo2.c
TERM='dumb' gcc -I /home/nsaboo/Documents/goworkspace/src/poc -fPIC -m64
-pthread -fmessage-length=0 -fdebug-prefix-map=$WORK/b001=/tmp/go-build
-gno-record-gcc-switches -I/usr/local/include/syslog-ng
-I/usr/local/include/syslog-ng/ivykis -I/usr/local/include/eventlog
-I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I ./
-g -O2 -I/usr/local/include/ -o ./_cgo_main.o -c _cgo_main.c
cd /home/nsaboo/Documents/goworkspace/src/poc
TERM='dumb' gcc -I . -fPIC -m64 -pthread -fmessage-length=0
-fdebug-prefix-map=$WORK/b001=/tmp/go-build -gno-record-gcc-switches -o
$WORK/b001/_cgo_.o $WORK/b001/_cgo_main.o $WORK/b001/_x001.o
$WORK/b001/_x002.o $WORK/b001/_x003.o -g -O2 syslog-node.so
-L/usr/local/lib/ -lsyslog-ng -L/usr/local/lib/syslog-ng -ldbparser
-L/usr/local/lib -Wl,--export-dynamic -lgmodule-2.0 -pthread -lgthread-2.0
-pthread -lglib-2.0 -lsyslog-ng -lglib-2.0 -levtlog
TERM='dumb' /usr/local/go/pkg/tool/linux_amd64/cgo -dynpackage main
-dynimport $WORK/b001/_cgo_.o -dynout $WORK/b001/_cgo_import.go
cat >$WORK/b001/importcfg << 'EOF' # internal
# import config
packagefile bufio=/usr/local/go/pkg/linux_amd64/bufio.a
packagefile encoding/json=/usr/local/go/pkg/linux_amd64/encoding/json.a
packagefile fmt=/usr/local/go/pkg/linux_amd64/fmt.a
packagefile os=/usr/local/go/pkg/linux_amd64/os.a
packagefile path=/usr/local/go/pkg/linux_amd64/path.a
packagefile runtime=/usr/local/go/pkg/linux_amd64/runtime.a
packagefile time=/usr/local/go/pkg/linux_amd64/time.a
packagefile runtime/cgo=/usr/local/go/pkg/linux_amd64/runtime/cgo.a
packagefile syscall=/usr/local/go/pkg/linux_amd64/syscall.a
EOF
/usr/local/go/pkg/tool/linux_amd64/compile -o $WORK/b001/_pkg_.a -trimpath
$WORK/b001 -p main -buildid 6VU9NC3t5EyTg_0nt_wU/6VU9NC3t5EyTg_0nt_wU
-goversion go1.12.4 -D _/home/nsaboo/Documents/goworkspace/src/poc
-importcfg $WORK/b001/importcfg -pack -c=2 $WORK/b001/_cgo_gotypes.go
$WORK/b001/main.cgo1.go $WORK/b001/cfuncs.cgo1.go $WORK/b001/_cgo_import.go
# command-line-arguments
./main.go:92:12: InitStruct.key_value_cb undefined (type unsafe.Pointer has
no field or method key_value_cb)
./main.go:93:12: InitStruct.data undefined (type unsafe.Pointer has no
field or method data)
./main.go:170:12: InitStruct.key_value_cb undefined (type unsafe.Pointer
has no field or method key_value_cb)
./main.go:171:12: InitStruct.data undefined (type unsafe.Pointer has no
field or method data)
makefile:6: recipe for target 'main' failed
make: *** [main] Error 2
Thanks,
Nitish
On Wed, Jul 10, 2019 at 9:20 PM andrey mirtchovski <mirtchov...@gmail.com>
wrote:
> the Go "Callback" struct may have completely different size and
> alignment than the C.Foo one expected by C.initialize_engine.
> therefore you want to construct the C version when calling
> C.initialize_engine, and the Go version for everything else. Your call
> may look something like this:
>
> initStruct := C.calloc(1, sizeof(C.Foo))
> initStruct.key_value_cb = C.callOnMeGo_cgo
> initStrudct.data: C.int(1)
>
> C.initialize_engine(pattern_db, module_path,
> (*C.Foo)(unsafe.Pointer(initStruct)))
>
> the Go Callback struct is not required unless you expect the callbacks
> to change or be settable by library clients, in which case you'll need
> to construct a more elaborate struct that implements locking and (at
> least what I do) a map between callback names and interface{} pointing
> to the callbacks sent by the library clients.
>
> On Wed, Jul 10, 2019 at 8:14 AM Nitish Saboo <nitish.sabo...@gmail.com>
> wrote:
> >
> > Hi Andrey,
> >
> > I am new to Go and cgo therefore did not exactly understand your point.
> > Can you explain me in the context of the code that I had posted.It will
> really help me to get hold of the things much better.
> >
> > Thanks,
> > Nitish
> >
> > On Wed, Jul 10, 2019 at 5:19 PM andrey mirtchovski <
> mirtchov...@gmail.com> wrote:
> >>
> >> what i do is have a similar struct in Go, and the original C one. here
> >> 'callbacks' is the go one, and
> >> "type Engine C.struct_cl_engine" is the opaque C one:
> >>
> >> https://github.com/mirtchovski/clamav/blob/master/callback.go#L63
> >>
> >> On Wed, Jul 10, 2019 at 5:25 AM Nitish Saboo <nitish.sabo...@gmail.com>
> wrote:
> >> >
> >> > Hi Andrey,
> >> >
> >> > I understand the issue here but how can I pass a callback function in
> a struct to C code.I need a struct because I want to pass and an extra
> parameter 'userdata' as well that I would require back as part of callback.
> >> >
> >> > Thanks,
> >> > Nitish
> >> >
> >> > On Wed, Jul 10, 2019 at 4:39 PM andrey mirtchovski <
> mirtchov...@gmail.com> wrote:
> >> >>
> >> >> i don't think you can use a go function directly in the callback. you
> >> >> need a correctly-typed C helper to do it. at least that used to be
> the
> >> >> case. see examples:
> >> >>
> >> >> https://github.com/mirtchovski/clamav/blob/master/cfuncs.go
> >> >> https://github.com/mirtchovski/clamav/blob/master/callback.go
>
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