Hi,
I'm trying to write a CGo shared library and I get a error always because I
found these two definition in
https://github.com/golang/go/blob/master/src/cmd/cgo/out.go
*typedef struct { const char *p; GoInt n; } GoString;*
*
_GoString_ GoString(char *p);*
I just wrote a simple sample code to reproduce the problem. Most of the sample
I found in Internet call C function from Go and that works well but my C
function want to call Go code so in my C I include the Header file of other Go
Shared library which contains the GO_CGO_PROLOGUE_H header definition so it
defines the GoString type. Go also defines the GoString function to convert C
string to Go string and due to the unfortunate name collision I don't know how
to avoid the compiler error. This code is just a short example in case anyone
know a solution so I can try it with my real world code.
So far the only solution if I completely avoid using the GO_CGO_PROLOGUE_H
header so from C I don't use any Goxxx types which makes impossible to do
Go->C->Go calls. So if my main code is in Go and I want to use it from C I must
write my project in C so do C->Go.
//go:binary-only-package
//package name: ecjni
package main
/*
#include <stdlib.h>
#ifndef GO_CGO_PROLOGUE_H
#define GO_CGO_PROLOGUE_H
typedef signed char GoInt8;
typedef unsigned char GoUint8;
typedef short GoInt16;
typedef unsigned short GoUint16;
typedef int GoInt32;
typedef unsigned int GoUint32;
typedef long long GoInt64;
typedef unsigned long long GoUint64;
typedef GoInt64 GoInt;
typedef GoUint64 GoUint;
typedef __SIZE_TYPE__ GoUintptr;
typedef float GoFloat32;
typedef double GoFloat64;
typedef float _Complex GoComplex64;
typedef double _Complex GoComplex128;
typedef char _check_for_64_bit_pointer_matching_GoInt[sizeof(void*)==64/8 ?
1:-1];
typedef struct { const char *p; GoInt n; } GoString;
typedef void *GoMap;
typedef void *GoChan;
typedef struct { void *t; void *v; } GoInterface;
typedef struct { void *data; GoInt len; GoInt cap; } GoSlice;
#endif
extern void printout(GoString p0);
void doC(const char* msg) {
GoString gs;
gs.p = msg;
gs.n = strlen(msg);
printout(gs);
}
*/
import "C"
//export printout
func printout(msg string) {
println(msg)
}
func calC(msg string) {
C.doC(C.CString(msg))
}
func main() {
println("go build -buildmode=c-shared -o libjni.dylib main.go")
calC("Hello")
}
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