Compilare: main.cpp:12:0: warning: ignoring #pragma GCC [-Wunknown-pragmas] #pragma GCC ("O3") main.cpp: In member function 'void InputReader<T>::advance() [with T = int]': main.cpp:27:5: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread (buffer, SIZE, 1, input_file) ; ^~~~~ main.cpp: In constructor 'InputReader<T>::InputReader(const char*) [with T = int]': main.cpp:35:4: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread (buffer, SIZE, 1, input_file) ; ^~~~~