diff.cpp: In member function 'void input_reader::advance()': diff.cpp:20: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result diff.cpp: In constructor 'input_reader::input_reader(const char*, const char*)': diff.cpp:32: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result diff.cpp: In constructor 'input_reader::input_reader(const char*, const char*)': diff.cpp:32: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result diff.cpp: In constructor 'input_reader::input_reader(const char*, const char*)': diff.cpp:32: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result