Google Protocol Buffers. C++ error: ‘google’ has not been declared

I'm trying to get the following simple C++ program to compile:

#include <stdio.h>
#include <stdlib.h>
using google::protobuf;

int main(void){
    printf("Hello\n")开发者_C百科;
    return 0;
}

I keep getting the following error:

error: ‘google’ has not been declared

I've linked to -lproto and have protobuf-compiler and libprotobuf-dev installed.

I'm totally stuck now.

Anyone have any ideas?

Many thanks in advance,

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You don't include any header which declares the google namespace. You should include the header file generated by the protoc compiler; it pulls in the necessary includes.

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You forgot to include the header for Protocol Buffers, so the google namespace is not declared.