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I am writing a c++ wallet and I need to be able to encode smart contract function calls in ABI format. I found that the web3 library has the ability, but it is written in JS. Is there a c++ alternative?

Thank you

Epic
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  • You can take the JS code and convert it to C++. – goodvibration Sep 22 '20 at 06:56
  • @goodvibration, I could, and could also call the JS but I prefer a native library over converting the code myself or raising a JS process and communicating with it. – Epic Sep 22 '20 at 07:05
  • I am aware of web3.js, web3.py and web3j (Java), with the first one being the most widely used. There might also be web3.php and web3.go. I have never encountered anything to imply that there's web3.cpp. – goodvibration Sep 22 '20 at 07:09
  • You may use the JSON RPC API of Ethereum (https://eth.wiki/json-rpc/API) – Markus Sprunck Sep 27 '20 at 07:17

2 Answers2

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i found two of them and it's really bad. One is 392 mb size haha. Really you don't need it if you deal with known contract. here is sample of token mint from cpp.

#include <sys/socket.h>
#include <netdb.h>
#include <iostream>
#include <sstream>
#include <openssl/bn.h>
#include <string>
#include <iomanip>
#include <algorithm>
#include "keccak.h"
#include <unistd.h>

int main(int argc , char argv[])
{
    Keccak keccak256(Keccak::Keccak256);
    std::stringstream f;
    const char et[] = "mint(address,uint256)";
    std::string ettag(keccak256(et), 0, 8);
    f << "0x" << ettag;
    std::string addr("0xF9cBf7b08f09ED3d4516E8b7A3FCbe4Dc7B3Cd40");
    std::string addrone(addr, 2, 40);
    f << std::setfill('0') << std::setw(64) << addrone; 
    unsigned long long c = 17000000000000000000ULL;
//  std::reverse((unsigned char)&c, (unsigned char)&c + 8);
    f << std::hex << std::setw(64) << c;
    std::cout << "and then " << f.str().c_str() << std::endl;
    int q;
    hostent host = gethostbyname("localhost");
    sockaddr_in server = {AF_INET, htons( 8545 ), ((unsigned long)host->h_addr)};
    q = socket(AF_INET , SOCK_STREAM , 0);
    connect(q, (sockaddr *)&server, sizeof(server));
    std::stringstream fvea;


fvea &lt;&lt; R&quot;({&quot;jsonrpc&quot;:&quot;2.0&quot;,&quot;method&quot;:&quot;eth_sendTransaction&quot;,&quot;params&quot;:[{&quot;from&quot;: &quot;0x031200BCE52f44EDd8e3988c09faBF106b508F86&quot;,&quot;to&quot;: &quot;0xEf49513C0261848b0e49c61f750Ec06a8d204AEe&quot;,&quot;gas&quot;: &quot;0x31f90&quot;,&quot;gasPrice&quot;: &quot;0xa111a000&quot;,&quot;value&quot;: &quot;0x0&quot;, &quot;data&quot;: &quot;)&quot; &lt;&lt; f.str() &lt;&lt; R&quot;(&quot;}], &quot;id&quot;:49})&quot;;
std::stringstream cp;
cp &lt;&lt; &quot;POST / HTTP/1.1\r\nContent-Length: &quot;&lt;&lt; fvea.str().length() &lt;&lt; &quot;\r\n\r\n&quot;&lt;&lt; fvea.str();
char b[2501]={};
send(q, cp.str().c_str(), cp.str().length(), 0);
recv(q, b, 2500, 0);
close(q);
std::cout &lt;&lt; b &lt;&lt; std::endl;



}

 c++ --std=c++17 '/home/alex/Desktop/etr/port.cpp' '/home/alex/Desktop/etr/keccak.cpp'   -o c
Алексей Неудачин
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0

There is. You can use libethc. An example for encoding ERC20 balanceOf call would be:

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <ethc/abi.h>

#define ok(ethcop) assert(ethcop >= 0)


int main(void) {
  struct eth_abi abi;
  char fn = "balanceOf(address)", addr="0x876D477Bd5cD050E6162cf757E1Bc02D93cdC0fE", *hex;
  size_t hexlen;


ok(eth_abi_init(&abi, ETH_ABI_ENCODE));


ok(eth_abi_call(&abi, &fn, NULL));  // balanceOf(
    ok(eth_abi_address(&abi, &addr)); //   0x876D477Bd5cD050E6162cf757E1Bc02D93cdC0fE
  ok(eth_abi_call_end(&abi));         // )


ok(eth_abi_to_hex(&abi, &hex, &hexlen));
  ok(eth_abi_free(&abi));
  printf("encoded abi: %s\n", hex); // encoded abi: 70a08231000000000000000000000000876d477bd5cd050e6162cf757e1bc02d93cdc0fe
  free(hex);
  return 0;
}
mhw0
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