Hi Tamas, I made it *C.Foo but still getting the error.
main.go ======= type Callback struct { Func func(*C.char , *C.char , C.size_t, C.int) UserData int32 } Calling C code in the following manner ========================================= C.initialize_engine(pattern_db, module_path, (*C.Foo)(unsafe.Pointer(&Callback{ Func: C.callOnMeGo_cgo UserData: C.int(1), }))) //export ParsedData func ParsedData(key *C.char, value *C.char, value_len C.size_t, work C.int) { fmt.Println("WORK:") fmt.Print() //performing some operation here } cfunc.go ========= package main /* #include <stdio.h> // The gateway function void callOnMeGo_cgo(char *key, char *value, size_t value_len, int work) { //printf("C.callOnMeGo_cgo(): called"); void ParsedData(const char *key, const char *value, size_t value_len, int work); ParsedData(key, value, value_len, work); } */ import "C" syslog-node.h =============== #ifndef _TEST_H_ #define _TEST_H_ #include <stdlib.h> typedef void (*key_value_cb)(const char* key, const char* value, size_t value_len, int work); typedef struct Foo{ key_value_cb cbnitish; int data; }Foo; int initialize_engine(const char* filename, const char* module_path, Foo *cb); int reload_pattern_db(const char* filename, Foo *cb); #endif syslog-node.c =============== gboolean pdbtool_accumulate_fields(NVHandle handle, const gchar *name, const gchar *value, gssize length, gpointer user_data) { user_data->cbnitish(name, value, length, user_data->data);// Callback happening here return FALSE; } Eventually user_data will get the instance of the struct. Looks like there is some issue with my struct declaration in Go.Can some please guide me as in what is the issue ? Error: ==== go build -v -x main.go cfuncs.go WORK=/tmp/go-build037176041 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 ZmTjWDq-3vSs8dJXUcwn/ZmTjWDq-3vSs8dJXUcwn -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:91:85: cannot use _Cgo_ptr(_Cfpvar_fp_callOnMeGo_cgo) (type unsafe.Pointer) as type func(*_Ctype_char, *_Ctype_char, _Ctype_ulong, _Ctype_int) in field value ./main.go:91:129: cannot use _Ctype_int(1) (type _Ctype_int) as type int in field value ./main.go:166:94: cannot use _Cgo_ptr(_Cfpvar_fp_callOnMeGo_cgo) (type unsafe.Pointer) as type func(*_Ctype_char, *_Ctype_char, _Ctype_ulong, _Ctype_int) in field value ./main.go:166:148: type _Ctype_int is not an expression makefile:6: recipe for target 'main' failed make: *** [main] Error 2 On Wed, Jul 10, 2019 at 2:28 PM Tamás Gulácsi <tgulacs...@gmail.com> wrote: > *C.foo > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/32a3a3c6-78e2-492d-9542-8a1c29deb600%40googlegroups.com > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CALjMrq6xBt145OtQdL4VuADL-OSv%3DN_-CSyoRkiXCQM%2BqpB49A%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.