Specifications

CAVR-4
Part 1. Using the compiler
The DLIB runtime environment
59
Choosing formatters for printf and scanf
To override the default formatter for all the printf- and scanf-related functions,
except for wprintf and wscanf variants, you simply set the appropriate library
options. This section describes the different options available.
Note:
● If you rebuild the library, it is possible to optimize these functions even further,
see Configuration symbols for printf and scanf, page 69
● For information about how to choose formatter for the AVR-specific functions
printf_P and scanf_P, see AVR–specific library functions, page 249.
CHOOSING PRINTF FORMATTER
The printf function uses a formatter called _Printf. The default version is quite
large, and provides facilities not required in many embedded applications. To reduce the
memory consumption, three smaller, alternative versions are also provided in the
standard C/EC++ library.
The following table summarizes the capabilities of the different formatters:
* Depends on which library configuration is used.
Formatting capabilities _PrintfFull _PrintfLarge
_PrintfSmall
(default)
_PrintfTiny
Basic specifiers c, d, i, o, p, s, u, X,
x, and %
Ye s Ye s Ye s Ye s
Multibyte support * * * No
Floating-point specifiers a, and A Ye s N o N o No
Floating-point specifiers e, E, f, F, g,
and G
Ye s Ye s N o N o
Conversion specifier n Ye s Ye s N o N o
Format flag space, +, -, #, and 0 Ye s Ye s Yes N o
Length modifiers h, l, L, s, t, and Z Ye s Ye s Ye s N o
Field width and precision, including * Ye s Ye s Ye s N o
long long support Yes Yes No No
Table 17: Formatters for printf