Question

我使用协议缓冲区模板在C ++中工作，包括以下消息：

message StringTable {
   repeated bytes s = 1;
}

我试图在现有数据中添加新值，如下所示：

pb.stringtable().s().Add(replace_key);

但是，这会在编译时产生错误（在OS X上使用clang）：

test.cpp:51:4: error: member function 'Add' not viable: 'this' argument 
  has type 'const ::google::protobuf::RepeatedPtrField< ::std::string>', 
  but function is not marked const
                    pb.stringtable().s().Add(replace_key);
                    ^~~~~~~~~~~~~~~~~~~~

任何线索？我非常喜欢C ++新手，所以可能会犯一个愚蠢的错误。

修改

使用访问器会产生类似的错误：

pb.stringtable().add_s(replace_key);

结果：

test.cpp:51:21: error: no matching member function for call to 'add_s'
                        pb.stringtable().add_s(replace_key);
                        ~~~~~~~~~~~~~~~~~^~~~~
./osmformat.pb.h:3046:26: note: candidate function not viable: 'this' argument has type 'const ::StringTable', but method is not marked const
inline void StringTable::add_s(const ::std::string& value) {
                     ^
./osmformat.pb.h:3050:26: note: candidate function not viable: 'this' argument has type 'const ::StringTable', but method is not marked const
inline void StringTable::add_s(const char* value) {
                     ^
./osmformat.pb.h:3043:36: note: candidate function not viable: requires 0 arguments, but 1 was provided
inline ::std::string* StringTable::add_s() {
                               ^
./osmformat.pb.h:3054:26: note: candidate function not viable: requires 2 arguments, but 1 was provided
inline void StringTable::add_s(const void* value, size_t size) {

Answer 1

问题解决了。

默认情况下，现有的StringTable不可变。但是，使用mutable_访问器可以实现：

pb.mutable_stringtable().add_s(replace_key);

添加到协议缓冲区重复字段

1 个答案: