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All of this I agree with. In a better world 'arrays' would have added in the 1980's. The arguments about memory limitations is spurious since if you're writing

All of this I agree with. In a better world 'arrays' would have added in the 1980's. The arguments about memory limitations is spurious since if you're writing good code you always pass a pointer and the length. Always no exceptions. Yeah and all the string functions should have been marked as depreciated with C89 and fully depreciated with C99.

mark-r 6y ago
Yes, you can always pass a pointer and a length explicitly. And that's what the "safe" versions of e.g. string functions do. But it's still incumbent on you as the programmer to use them properly. It would still be beneficial to have a compiler mode where all that was done for you automatically and it was impossible to have a buffer overrun.
- Gibbon1 6y ago
  The safe string functions aren't safe because they don't return safe strings.
jstimpfle 6y ago
There is a difference between passing a length as a function argument, and actually storing string lengths alongside the strings in memory. It's not unheard of to have millions of tiny little (< 10 character) strings, and not storing lengths alongside them can shave off a sizeable portion of space requirements.
- WalterBright 6y ago
  Anytime a program has a special case like that, it makes sense to craft an optimal data structure for it. Also, consider that the terminating 0 byte isn't just one byte. There's also the alignment of what malloc returns, which may be 4 or 8 or even 16 bytes.
  - jstimpfle 6y ago
    malloc also has internal bookkeeping overhead, typically 16-32 bytes per allocation. Which is why one should never allocate a single (short) string from a generic allocator. Instead, one allocates a big chunk upfront (e.g. 4K bytes or more), and breaks from that, using a simple index that points to the first unused bytes. In this way, the overhead of allocating a string is truly only the terminating zero byte - no alignment constraints. This scheme is easy to implement as long as strings don't need to be freed individually.

mark-r 6y ago

Yes, you can always pass a pointer and a length explicitly. And that's what the "safe" versions of e.g. string functions do. But it's still incumbent on you as the programmer to use them properly. It would still be beneficial to have a compiler mode where all that was done for you automatically and it was impossible to have a buffer overrun.

Gibbon1 6y ago
The safe string functions aren't safe because they don't return safe strings.

jstimpfle 6y ago

There is a difference between passing a length as a function argument, and actually storing string lengths alongside the strings in memory. It's not unheard of to have millions of tiny little (< 10 character) strings, and not storing lengths alongside them can shave off a sizeable portion of space requirements.

WalterBright 6y ago
Anytime a program has a special case like that, it makes sense to craft an optimal data structure for it. Also, consider that the terminating 0 byte isn't just one byte. There's also the alignment of what malloc returns, which may be 4 or 8 or even 16 bytes.
- jstimpfle 6y ago
  malloc also has internal bookkeeping overhead, typically 16-32 bytes per allocation. Which is why one should never allocate a single (short) string from a generic allocator. Instead, one allocates a big chunk upfront (e.g. 4K bytes or more), and breaks from that, using a simple index that points to the first unused bytes. In this way, the overhead of allocating a string is truly only the terminating zero byte - no alignment constraints. This scheme is easy to implement as long as strings don't need to be freed individually.