   Error when using non initialized variable(runtime check failure)
  Whats the problem when accessing non initialized variables? Why Im getting erros, and not just a warning? In release mode no error happens..I have this situation:I_HOLDER i_values;//locali_values.iMeshID = 5; //this is oksscanf_s( &Line[2], "%i", i_values.iMeshID ); //runtime check failure #3(just on debug)File_p>>i_values.iMeshID;// this is the most problematic, it doesnt generates any error, but the application just freezes forever(debug or release)I dont get whats the problem, I know its good pratice zero everything before use it, since its not anyone objective to use junk values, but I dont see why it generates errors.   
  For sscanf_s shouldn't it be &i_values.iMeshID ?   ;  yeah, it do.. nothing to do with what i was thinking. Solved, thanx.   ;  I'm going to guess that you're using visual studio. In which case the answer as to why it generates errors in debug mode is that that's the point of debug mode -- it will detect those sorts of errors. In release mode, it's not chucking out errors, but it won't be working properly either.