libprotobuf ERROR google/protobuf/wire_format.cc:1059

使用google::protobuf進行序列化，在運行時有如下警告！

libprotobuf ERROR google/protobuf/wire_format.cc:1059] Encountered string containing invalid UTF-8 data while serializing protocol buffer. Strings must contain only UTF-8; use the 'bytes' type for raw bytes.

libprotobuf ERROR google/protobuf/wire_format.cc:1059] Encountered string containing invalid UTF-8 data while serializing protocol buffer. Strings must contain only UTF-8; use the 'bytes' type for raw bytes.

原因：要求所有的string類型都必須為UTF-8類型的，可以使用<iconv.h> 進行格式轉化。

先面貼一段轉化的代碼：

include <string>
#include <stdlib.h>
#include <iostream>
using namespace std;
#include <iconv.h>
bool convertGbk2Utf(string& instr, string& outstr)
{
                iconv_t     gbk2UtfDescriptor;
                gbk2UtfDescriptor = iconv_open("UTF-8", "GBK");
                size_t inlen = instr.length();
                char* in = const_cast<char*>(instr.c_str());
                size_t outlen = inlen * 2 + 1; // inlen * 1.5 + 1 >= outlen >= inlen + 1
                char* outbuf = (char*)::malloc(outlen);
                char* out = outbuf;
                memset(outbuf, 0x0, outlen);
                if((size_t)-1 == iconv(gbk2UtfDescriptor, &in, &inlen, &out, &outlen))
                {
                                ::free(outbuf);
                                return false;
                }
                outstr.clear();
                outstr.append(outbuf);
                ::free(outbuf);
                return true;
}
int main()
{
                string str = "黃";
                convertGbk2Utf(str,str);
                cout << str << endl;
}