WebJan 22, 2013 · This is a macro. Whenever the preprocessor hits a statement like Bitset(var,bitno) it faithfully replaces it with . var = var 1UL << (bitno) Further to explain this. UL here means Unsigned Long.. Operator is used for bitwise OR operation. so the variable var is ORed with 1UL << bitno and assigned back to var. Then during runtime or compile … WebMy experience has been having bit masks for multiple bits is much easier. So the individual bits are identified with a particular define whose name indicates the function of the bit as in. #define ENABLE_T1 0x0001 #define ENABLE_T2 0x0002 and then these are used with the bitwise operators to turn bits on and off.
Macros for bitsets / bit-flags in C - Code Review Stack …
WebSep 9, 2016 · If I am not too late, this page gives awesome explanation with examples. An array of int can be used to deal with array of bits.Assuming size of int to be 4 bytes, when we talk about an int, we are dealing with 32 bits.Say we have int A[10], means we are working on 10*4*8 = 320 bits and following figure shows it: (each element of array has 4 … WebAug 19, 2016 · Starting with any bit pattern, when we shift right by 1 and take the OR, adjacent bits will become 1. Example. 00010100 00001010 ----- 00011110 You repeat this until you have all ones to the right of the leading digit, by successively shifting 2, 4, 8, 16 (if you have 32 bit numbers; for larger int you keep going). speed gear
Interesting Facts about Macros and Preprocessors in C
WebAug 29, 2024 · A mask defines which bits you want to keep, and which bits you want to clear. Masking is the act of applying a mask to a value. This is accomplished by doing: Below is an example of extracting a subset of the bits in the value: Applying the mask to the value means that we want to clear the first (higher) 4 bits, and keep the last (lower) 4 bits. WebFeb 1, 2024 · Use the struct Keyword to Define Bitmask Data in C ; Use struct Combined With union to Define Bitmask Data in C ; This article will demonstrate multiple methods … WebFeb 1, 2016 · It is a recursive macro that is scanned multiple times to expand the recursive replacements. It handles a variable number of arguments and supports integers up to 64 bits. // test.c #include "bits.h" int a = BITS(1,5,7); int b = BITS(3); int c = BITS(); // This case is broken but irrelevant Using gcc -E test.c -o test.txt this expands to: speed gcse bitesize