преобразование входного формата (input format conversion)
Стандарты (Conforming to)
The functions fscanf(), scanf(), and sscanf() conform to C89 and
C99 and POSIX.1-2001. These standards do not specify the ERANGE
error.
The q specifier is the 4.4BSD notation for long long, while ll or
the usage of L in integer conversions is the GNU notation.
The Linux version of these functions is based on the GNU libio
library. Take a look at the info documentation of GNU libc
(glibc-1.08) for a more concise description.