EOS Hello World Discussion

Blockchain Programming Course
#1

Welcome to the thread about EOS Hello World. Here you can discuss everything about the Hello World code and potential problems that you might stumble upon.

#2

My CMakeLists.txt is showing up red in its tab and there is an error when I try to deploy the contract. I do not see any typos. Help?

file(GLOB ABI_FILES ā€œ*.abiā€)
configure_file("${ABI_FILES}" ā€œ${CMAKE_CURRENT_BINARY_DIR}ā€ COPYONLY)

add_wast_executable(TARGET HelloWorld
INCLUDE_FOLDERS ā€œ${STANDARD_INCLUDE_FOLDERS}ā€
LIBRARIES libc libc++ eosiolib
DESTINATION_FOLDER ${CMAKE_CURRENT_BINARY_DIR}
)

#3

The CMake file could show up red sometimes in CLion. Sometime it helps to restart it. Whatā€™s the error you got when deploying?

#4

I do not know what I did different, but the error went away.

#5

While Filip had us use CLion, you can use a text editor and write your program this way, and afterward invoke eosiocpp for compilation to wasm & abi. CLion for me just got in the way. He also suggested Atom as an IDE, if you like color sensing and more advanced tooling.

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#6

1.) What is the ā€œeosioā€ account that gets referenced? From my own research, it appears that this is an authorizing account used to bootstrap EOSIO nodes. But Iā€™d like more info. if itā€™s available. Is this pseudo account native to every EOS blockchain? Is this a pseudo account that makes use of the private key listed in the genesis.json file?

I bring up ā€œeosioā€ here because we need to use it to create a new account, to which we deploy our contracts.

2.) What is ā€œnameā€ exactly from this contract? Is it a custom variable type created by EOS? And why do we wrap ā€œuserā€ around it in our hello world example? e.g. name{user}

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#7

Okay, I understand what ā€œnameā€ is referencing now.
This below is from the EOSIO source repo.

struct name {
      operator uint64_t()const { return value; }

      // keep in sync with name::operator string() in eosio source code definition for name
      std::string to_string() const {
         static const char* charmap = ".12345abcdefghijklmnopqrstuvwxyz";

         std::string str(13,'.');

         uint64_t tmp = value;
         for( uint32_t i = 0; i <= 12; ++i ) {
            char c = charmap[tmp & (i == 0 ? 0x0f : 0x1f)];
            str[12-i] = c;
            tmp >>= (i == 0 ? 4 : 5);
         }

         trim_right_dots( str );
         return str;
      }

      friend bool operator==( const name& a, const name& b ) { return a.value == b.value; }
      account_name value = 0;

   private:
      static void trim_right_dots(std::string& str ) {
         const auto last = str.find_last_not_of('.');
         if (last != std::string::npos)
            str = str.substr(0, last + 1);
      }
   };
   /// @}
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#8

Hi Siege17, I couldnā€™t get CLion to work and am using Atom, which seems to work fine. Can I ask how I would build after making change? I used Codeblocks during the C++ portion of this course and everything (inc CLion) is automated (click button). Any help would be highly appreciated. Thanks

#9

I installed cmake packages in atom, but now getting errors:
CMake Error at CMakeLists.txt:1 (cmake_minimum_required):
CMake 3.12 or higher is required. You are running version 3.10.2

when I ā€˜sudo apt-get updateā€™, I get nothing to update?

Any help help from anyone would be greatly appreciated.

Cheers,
kuki

#10

Okay, so Iā€™ve updated cmake to 3.12. Now I canā€™t build ā€˜sudo make installā€™ in the ~/eos/build directory. I get ā€œnothing to buildā€

Any help is highly appreciated. Thanks

#11

I think you can simply use the eosiocpp command line tool to compile it to wasm and abi. That should be enough.

#12

getting an error

eos/contracts/hello$ eosiocpp -o hello.wast hello.cpp
In file included from hello.cpp:1:
In file included from /usr/local/include/eosiolib/eosio.hpp:7:
In file included from /usr/local/include/eosiolib/action.hpp:7:
/usr/local/include/eosiolib/datastream.hpp:9:10: fatal error: ā€˜boost/container/flat_map.hppā€™ file not found
#include <boost/container/flat_map.hpp>

tried doing the eos/build sudo make install again. and did brew install boost. anyone have some other ideas on what might be going wrong?

#13

Was the eos installation successfull or did you get any errors?

#14

installation seemed fine, when i run the test i get errors

27/41 Test #27: unit_test_binaryen ā€¦***Failed 104.31 sec
28/41 Test #28: unit_test_wavm ā€¦***Exception: SegFault386.63 sec
34/41 Test #34: nodeos_run_test-mongodb ā€¦***Failed 0.31 sec

also having lots of problems with nodeos, always getting block log configuration errors. So i used a walkthrough for the multinode test and that seemed to start producing blocks, it crashed. Right now i canā€™t get either to work.

#15

Iā€™m not sure whatā€™s causing that unfortunately. I will do some research and see if I find something. In the meantime I would recommend you to check out the lecture about the eos test/main net. So that you could continue with the eos section using the testnet instead of local.

#16

ok thanks, i might try installing a virtual machine on my other computer and see if i run into the same issues

#17

Iā€™m running Ubuntu as VM. EOS builds fine and single node produces blocks, so no problem up till now. But once HelloWorld sample created as shown in the lecture Iā€™m unable to build EOS. Iā€™m getting all sort of errors. These are all originated from very first line in HelloWorld.cpp which is exactly same as ā€˜hello.cppā€™
#include <eosiolib/eosio.hpp>

Iā€™m getting following errors:
In file included from /usr/include/features.h:424:0,
from /usr/include/x86_64-linux-gnu/bits/libc-header-start.h:33,
from /usr/include/stdint.h:26,
from /usr/lib/gcc/x86_64-linux-gnu/7/include/stdint.h:9,
from /home/navi/eos/contracts/exchange/../eosiolib/types.h:7,
from /home/navi/eos/contracts/exchange/../eosiolib/types.hpp:6,
from /home/navi/eos/contracts/exchange/../eosiolib/eosio.hpp:6,
from /home/navi/eos/contracts/HelloWorld/HelloWorld.cpp:1:
/usr/include/time.h:75:38: error: ā€˜time_t time(time_t*)ā€™ redeclared as different kind of symbol
extern time_t time (time_t *__timer) __THROW;

    /home/navi/eos/contracts/exchange/../eosiolib/types.hpp:13:17: error: ā€˜vectorā€™ in namespace ā€˜stdā€™ does not name a template type
        typedef std::vector<std::tuple<uint16_t,std::vector<char>>> extensions_type;
                 ^~~~~~
/home/navi/eos/contracts/exchange/../eosiolib/types.hpp: In member function ā€˜bool std::less<checksum256>::operator()(const checksum256&, const checksum256&) constā€™:
/home/navi/eos/contracts/exchange/../eosiolib/types.hpp:142:17: error: ā€˜memcmpā€™ was not declared in this scope
          return memcmp(&lhs, &rhs, sizeof(lhs)) < 0;

/home/navi/eos/contracts/exchange/../eosiolib/print.h:86:26: error: ā€˜int128_tā€™ does not name a type; did you mean ā€˜int32_tā€™?
    void printi128( const int128_t* value );
/home/navi/eos/contracts/exchange/../eosiolib/fixed_key.hpp:94:37: error: ā€˜word_tā€™ was not declared in this scope
          fixed_key(const std::array<word_t, num_words()>& arr)

There are few other errors similar to the above complaining about print(), begin(), uint128_t etc. Any help will be much appreciated.

#18

Did you execute the command ā€œsudo make installā€ after building eos?

#19

Thanks, Filip. Yes, i mustā€™ve missed that. It works now. Thanks a lot.

#20

finally able to compile hello.abi took me awhile.

had to run a VM on my new computer. Not sure why old computer has 8gb of ram, but it is over 5 years old

Then change my bios settings to allow for virtual machines

after installation still had problems with compiling hello.wast, used the commands

cd $HOME/eos
git revert -n 67393d7
./eosio_build.sh
cd build
sudo make install

software really pisses me off sometimes, i spent a few days trying to get this to work. Always seems like fixing one thing leads to more problems.