Cant seem to understand declarations in header

[Yulia]

on my understanding headers should contain declaration and its definition will be on the cpp.

  bool IsTrialEndAward() { return ( m_emTrialState == TRIAL_END_AWARD); }

This is inside the header and i cant seem to understand the logic whenever you will be using this function.

[JLBorges]

It appears to be an (implicitly) inline member function.

2) A function defined entirely inside a class/struct/union definition, whether it's a member function or a non-member friend function, is always inline.
http://en.cppreference.com/w/cpp/language/inline