I am trying to build a contract and receiving this error:

In file included from /usr/opt/eosio.cdt/1.6.1/bin/../include/eosiolib/contracts/eosio/system.hpp:6:[0K
/usr/opt/eosio.cdt/1.6.1/bin/../include/eosiolib/contracts/eosio/../../core/eosio/time.hpp:157:20: error: no member named 'check' in namespace 'eosio'[0K
eosio::check( std::numeric_limits<uint32_t>::max() - slot >= 1, "block timestamp overflow" );[0K

Any idea what is causing this error and how to fix it?

  • Can you include more code relating to the contract you are trying to build. Most importantly the header includes you are using. The specific error you are getting here is no member named 'check' in namespace 'eosio' Commented Jul 25, 2019 at 9:53

1 Answer 1


You need to include eosio.hpp before the other includes.

#include <eosio/eosio.hpp>

Sidenote: this actually seems to be a problem with cdt 1.6.1 and will hopefully be fixed with next releases Issue#532

  • Can you add a link to the Github issue for your sidenote if you know it? Commented Jul 26, 2019 at 10:51
  • Done. See above.
    – cmadh
    Commented Jul 27, 2019 at 2:18

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