golang 通过 cgo 调用 C++ 库

思路

将 C++ 库包装成 C 库 -> golang 通过 cgo 调用 C 库

C ++ 相关文件

目录列表

• include/
  • some.h C++ 库头文件
  • some_wrapper.h <= 用于将 C++ 库包装成 C 库的头文件
• lib/
  • libsome.a C++ 库
• src/
  • some_wrapper.cpp <= 用于将 C++ 库包装成 C 库的源码文件

源码示例

some.h

#ifndef SOME_H
#define SOME_H#include <string>
#include <utility>
#include <vector>namespace Some {struct DeviceInfo {std::string id;};std::vector<std::pair<std::string, std::string>> Generate(const DeviceInfo& device);
}#endif  // SOME_H

some_wrapper.h

#ifndef SOME_WRAPPER_H
#define SOME_WRAPPER_H#ifdef __cplusplusextern "C" {#endifstruct some_item {char version[8];char value[32];};struct some_result {struct some_item data[1];int size;};int generate(struct some_result* result, char* id);#ifdef __cplusplus}#endif#endif // SOME_WRAPPER_H

some_wrapper.cpp

#include <string.h>
#include "some.h"
#include "some_wrapper.h"#ifdef __cplusplus
extern "C" {
#endifint generate(struct some_result* result, char* id) {Some::DeviceInfo deviceInfo;deviceInfo.id = id;auto v = Some::Generate(deviceInfo);strcpy(result->data[0].version, v.first.data());strcpy(result->data[0].value, v.second.data());result->size = 1;return 0;}#ifdef __cplusplus
}
#endif

将 C++ 库包装成 C 库

# 编译生成 src/some_wrapper.o 临时目标文件
g++ -c -Iinclude src/some_wrapper.cpp -o src/some_wrapper.o# 生成静态库 lib/libsomewrapper.a
ar -cr lib/libsomewrapper.a src/some_wrapper.o# 删除临时目标文件
rm -rf src/some_wrapper.o

Golang CGO 调用 C 库

package main// #cgo CFLAGS: -I  ${SRCDIR}/include
// #cgo LDFLAGS: -L ${SRCDIR}/lib -lsomewrapper -lsome -lstdc++
// #include <stdlib.h>
// #include "some_wrapper.h"
import "C"
import ("unsafe"
)type DeviceInfo struct {ID string `json:"id"`
}func main() {di := DeviceInfo{ID: "123456",}cID:= C.CString(di.ID)defer C.free(unsafe.Pointer(cID))some := &C.struct_some_result{}C.generate(some, cId)if len(some.data) > 0 {item := some.data[0]version := C.GoStringN(&(item.version[0]), 8)value := C.GoStringN(&(item.value[0]), 32)result := make(map[string]string, someSize)result[version] = valuesomeSize := int(some.size)fmt.Println(result, someSize)}
}

# 编译 go 文件
go install -v# 运行
$GOPATH/bin/demo

参考

• https://pkg.go.dev/cmd/cgo
• https://stackoverflow.com/questions/41811563/do-i-have-to-free-structs-created-with-cgo