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/GCC 7

6.65 Binary Constants using the ‘0b’ Prefix

Integer constants can be written as binary constants, consisting of a sequence of ‘0’ and ‘1’ digits, prefixed by ‘0b’ or ‘0B’. This is particularly useful in environments that operate a lot on the bit level (like microcontrollers).

The following statements are identical:

i =       42;
i =     0x2a;
i =      052;
i = 0b101010;

The type of these constants follows the same rules as for octal or hexadecimal integer constants, so suffixes like ‘L’ or ‘UL’ can be applied.

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Licensed under the GNU Free Documentation License, Version 1.3.
https://gcc.gnu.org/onlinedocs/gcc-7.3.0/gcc/Binary-constants.html