cannot resolve LNK2005 multiply defined symbols

Bryan Kelly 266 Reputation points

Windows 11, Visual Studio 2019, C++
I started getting this error:

1>ripemd_160_test_data.obj : error LNK2005: "char (* ripemd_input)[90]" (?ripemd_input@@3PAY0FK@DA) already defined in ripemd_160_13.obj

1>E:\WX\ripemd_160_13\Debug\ripemd_160_13.exe : fatal error LNK1169: one or more multiply defined symbols found

I have removed almost all the code with only one instance of that item and still get the error. Here is the main project file:

include <iostream>

include "ripemd_160_test_data.h"

int main()
std::cout << "Hello World!\n";

Yeah, that it. Here is the utility include file.

#pragma once  
#ifndef RIPEMD_160_TEST_DATA_H  
#define RIPEMD_160_TEST_DATA_H  

#include <stdint.h>  
#include <string>  

const size_t rm_count = 8;  
const size_t max_in = 90;  

char ripemd_input[rm_count ][ max_in ] =  
   { "a" }  
// deleted stuff  


Please note the #pragma and the #define.
And here is the cpp file.

// test data for RIPEMD-160 test data  
// A RIPEMD-160 output is always the same length.  

#include "ripemd_160_test_data.h"  

Yeah, it down to just that.

I have done a clean and build and continue to get that same error. There is nothing left to remove.
What am I doing wrong.

Edit: I did use the "101010" tool to mark the code as such and it did not work.
Edit: And I started a new console project and added just those two files to the project, nothing else. The error is still there.

A high-level, general-purpose programming language, created as an extension of the C programming language, that has object-oriented, generic, and functional features in addition to facilities for low-level memory manipulation.
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Accepted answer
  1. Minxin Yu 4,826 Reputation points Microsoft Vendor

    Hi, @Bryan Kelly

    The problem is that global variable is being accessed by multiple files.

    Modified snippet:

    extern char ripemd_input[rm_count][max_in];   


    #include "ripemd_160_test_data.h"  
    char ripemd_input[rm_count ][ max_in ] =  
    { "a" }  
    // deleted stuff  

    Best regards,

    Minxin Yu

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  1. Bryan Kelly 266 Reputation points

    Did you look at the "#pragma once"
    Did you look at the "#ifndef ..."
    Both of those commands to the compiler were designed to prevent it from creating the item multiple times.
    I started using that stuff back in the 1980s and 1990s.

    If it is declared "external" in the h file, then it is "external" to the h file, and every file that incorporates the h file sees it declared external, and there is nothing left to actually create that entity.

  2. Bryan Kelly 266 Reputation points

    I stepped away for a while and thought about this deeply. Your point(s) are getting through to me.
    Thank you for your time and patience.

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