pragma(pack) {
int a:1, b:1, ... h:1;
}
IIRC.
this post was submitted on 15 May 2025
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I swore I read that mysql dbs will store multiple bools in a row as bit maps in one byte. I can't prove it though
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(2 replies)
I mean is it really a waste? What's minimum amount of bits most CPUs read in one cycle.
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Could a kind soul ELI5 this? Well, maybe ELI8. I did quite a bit of programming in the 90-00s as part of my job, although nowadays I'm more of a script kiddie.
A boolean value only needs 1 bit (on or off) for true or false. However the smallest bit of addressable memory is a byte (8 bits) hence 7 are technically wasted.
For low memory devices you could instead store 8 different Boolean values in one single byte by using bit masking instead
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Pl/1 did it right:
Dcl 1 mybools, 3 bool1 bit(1) unaligned, 3 bool2 bit(1) unaligned, … 3 bool8 bit(1) unaligned;
All eight bools are in the same byte.
Does anybody ever figure in parity when comparing bit sizes and all that jazz or are we only ever concerned with storage space?
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(1 replies)
Now store the numbers (array):
0 0 0 1 0 1 1 2
think 8 bytes???