ch2-6-call-c-sum-v2.plantuml

' Copyright 2017 <chaishushan{AT}gmail.com>. All rights reserved.
' Use of this source code is governed by a Apache
' license that can be found in the LICENSE file.

@startuml

title c call go func

|_testmain.c|
:int main() {
	extern int sum(int a, int b)
	sum(1, 2)
	return 0
};
-[#green,dashed]->

fork

|#AntiqueWhite|_cgo_export.c|
:int sum(int p0, int p1) {
	struct { int p0, p1, r0; } a
	_cgo_ctxt = _cgo_wait_runtime_init_done()
	crosscall2(_cgoexp_xxx_sum, &a, 16, _cgo_ctxt)
	_cgo_release_context(_cgo_ctxt)
	return a.r0
};

|runtime/cgo/*.asm|
:TEXT crosscall2(SB),NOSPLIT,$0;

fork

|#AntiqueWhite|_cgo_types.go|
:func _cgoexp_xxx_sum(a unsafe.Pointer, n int32, ctxt uintptr) {
	fn := _cgoexpwrap_xxx_sum
	_cgo_runtime_cgocallback(
		_cgoexpwrap_xxx_sum,
		...
	)
};

|#AntiqueWhite|_cgo_types.go|
:func _cgoexpwrap_xxx_sum(p0, p1) r0 {
	return sum(p0, p1)
};

|main.go|
://export sum
func sum(a, b C.int) C.int {
	return a + b
};

endfork

|runtime/cgo/*.asm|
:TEXT crosscall2(SB),NOSPLIT,$0;

endfork

|_testmain.c|
stop

@enduml