Thread: Help with claims

  1. #1
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    Help with claims

    i am beginner in c and there are two claims i dont know if they are true

    1.To read bytes you can use system call "read", but it is recommended to read one byte in each reading, and not read all the houses together.

    2.When you want to save memory, you can use bit-field. This way you can "pack" several objects in one memory word and refer to the address of each bit, using the "&" address operator.
    thank you!

  2. #2
    and the hat of int overfl Salem's Avatar
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    The first is at best dubious. There might be odd cases where reading 1 byte at a time may be useful, but as a blanket rule, it's false.

    The second is out and out rubbish. Bit fields can't be addressed with &.
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  3. #3
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    1. I'm not sure where you got the recommendation to read one byte at a time with the "read" system call. It's very common to read a large buffer full at a time to minimize overhead (system calls are "slow" compared to user code).

    2. Bit fields are not addressable. The smallest addressable unit in C is char.

  4. #4
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    For #2, I'd guess that you have mixed up the address-of operator with the bitwise and operator. They both use the & symbol but with very different syntax and semantics.
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