3 ms·

I mean, reading zeroed out memory is not really incorrect behaviour anyway. If you know that it was zeroed out, then you're really just reading memory that was

I mean, reading zeroed out memory is not really incorrect behaviour anyway. If you know that it was zeroed out, then you're really just reading memory that was initialised with a specific default value. That being said, zeroing out everything you allocate will make it difficult for the kernel's paging system to defer allocating you a physical page until you actually need it, so you will need to be a lot more careful with your allocations if your application uses relatively large amounts of memory and you need to work with memory constraints.

rc4algorithm 11y ago
Unless the zeroing is defined by the language, assuming it t is incorrect and shouldn't be done.
- lmm 11y ago
  Calloc is defined to return memory that's all-bits-zero, which in turn defines the value for many datatypes. The overwhelming majority of C implementations additionally define the values of all-bits-zero floats and pointers. IMO it's reasonable to write programs targeting only such implementations, provided such a dependency is clearly documented (just as e.g. it's reasonable to write C programs targeting only implementations on which floating-point arithmetic is IEEE 754, despite this not being required by the C standard).
  - rc4algorithm 11y ago
    > The overwhelming majority of C implementations additionally define the values of all-bits-zero floats and pointers. So... Clang and GCC? Regardless, you're ignoring the obvious difference: that isn't POSIX- or ISO-defined at all. If you choose to use it, you're using a weird dialect. Might as well just switch to Cyclone.
    - lmm 11y ago
      > that isn't POSIX- or ISO-defined at all. If you choose to use it, you're using a weird dialect. People used C (even on multiple compilers) long before POSIX or ISO. You're putting the standardization cart before the compatibility horse.
      - rc4algorithm 11y ago
        Yeah, let's revert to 1988! Great solution! Muchly of advance!

rc4algorithm 11y ago

Unless the zeroing is defined by the language, assuming it t is incorrect and shouldn't be done.

lmm 11y ago
Calloc is defined to return memory that's all-bits-zero, which in turn defines the value for many datatypes. The overwhelming majority of C implementations additionally define the values of all-bits-zero floats and pointers. IMO it's reasonable to write programs targeting only such implementations, provided such a dependency is clearly documented (just as e.g. it's reasonable to write C programs targeting only implementations on which floating-point arithmetic is IEEE 754, despite this not being required by the C standard).
- rc4algorithm 11y ago
  > The overwhelming majority of C implementations additionally define the values of all-bits-zero floats and pointers. So... Clang and GCC? Regardless, you're ignoring the obvious difference: that isn't POSIX- or ISO-defined at all. If you choose to use it, you're using a weird dialect. Might as well just switch to Cyclone.
  - lmm 11y ago
    > that isn't POSIX- or ISO-defined at all. If you choose to use it, you're using a weird dialect. People used C (even on multiple compilers) long before POSIX or ISO. You're putting the standardization cart before the compatibility horse.
    - rc4algorithm 11y ago
      Yeah, let's revert to 1988! Great solution! Muchly of advance!