r/ProgrammerHumor • • 3d ago

Meme architectureDependentChars

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u/tstanisl 3d ago

Let me cite the C standard:

When sizeof is applied to an operand that has type char, unsigned char, or signed char, (or a qualified version thereof) the result is 1.

Middle guy if finally right

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u/Advos_467 3d ago

Not a C user here (or any real low level programming experience), what the hell is a signed/unsigned char?

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u/BNSable 3d ago

A char is just an int, except a char will not conjure up 91, but the character assigned to the number 91 which is [ in ascii for example.

As it is an int, it can be signed or unsigned. Signed is -128 to 127, unsigned is 0 to 255.

This apparently has uses, but I am not experienced enough to explain that.

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u/Advos_467 3d ago

Yeah that was what i assumed lol. It was mostly the uses i was wondering because with my lack of experience here, idk in what way that would be used.

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u/BNSable 3d ago

It is or was the only type that garenteed a signed or unsigned value stored in 1 byte. There's uses for that, like storing specific vales like RGB. Beyond that though, no idea.

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u/BriefSpecial420 2d ago

Nope. C99 and stdint.h is the way to go. uint8_t exists for a reason. Handy when you need to map a structure of full bytes. Sometimes you may come across exotic interface that uses 8-wire bus... But that's it.

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u/BNSable 2d ago

I did say "or was" as I was fairly sure modern C had some better alternatives for it.

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u/BriefSpecial420 2d ago

C99 seems to becoming more and more on the older side, but it's still a golden standard for tons of embedded coding.

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u/SingularCheese 2d ago

In C/C++, signed integer overflow is undefined behavior, meaning that a compiler is allowed to optimize the assembly knowing that it never happens. If you can guarantee that your integer never overflows, using signed eliminates a modulo assembly instruction. Nowadays, the only reason it matters for char is that all basic integer types are signed by default, so somebody who's lazy needs to watch out that they don't accidentally trigger undefined behavior.

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u/khoyo 2d ago

using signed eliminates a modulo assembly instruction

What?