4 ms·

> It balkanizes the language. Not really, as C has had even more diverse implementations per-standardization. I would say the situation is now, much less dive

> It balkanizes the language. Not really, as C has had even more diverse implementations per-standardization. I would say the situation is now, much less diverse under the rule of GCC and Clang. (Yeah MSVC also exists.)

WalterBright 10mo ago
Every switch that changes the language semantics creates a separate language. If you have n such switches, your compiler is supporting n x n languages. I've also had troubles writing portable C code with all warnings enabled as different compilers contradicted each other on what was acceptable. I tried pretty hard to make D a warning-less language, but still some crept in grump grump. Have fun with this one: for (int i = 0; i < end; ++i); foo(i); One of the best programmers I know came up to me with this loop and told me my C compiler was broken because the loop was only executed once. I pointed at the ; and you can guess the rest. I added a warning for that in the C compiler, and for D simply disallowed it. I've noticed that some C compilers have since added a warning for that as well. The C folks should just make it illegal. I've also fixed printf in D so that: char* p; printf("%d\n", p); gives an error message, and the right format to use for `p`. It was a little thing, but it sure found a lot of incorrect formats in my code.
- 1718627440 10mo ago
  > The C folks should just make it illegal. I often have code, which looks like this: for (ptr = start; random_condition (*ptr); ptr = ptr->next); for (ptr = ptr->next; other_condition (*ptr); ptr = ptr->prev); ... [do action] for (ptr = end; to_be_deleted (*ptr) && (delete (ptr), TRUE); ptr = ptr->prev); I wouldn't be happy about your policy. > I've also fixed printf in D so that [...] gives an error message Just last week I had the case that the C compiler complained, I should use %lld for long long, but the printf implementation shipped with the compiler doesn't support that. Thus, using %ld, even if undefined behaviour was the correct action. I wouldn't like my language making up more work for me for no reason.
  - WalterBright 10mo ago
    Rewrite as: for (ptr = start; random_condition (*ptr); ptr = ptr->next) { } Then anyone reading your code will know the empty loop was intentional. BTW, many C compilers warn about the ; on a for loop. Have you ever discovered this bug: if (condition); doThis(); It's a hard one to see in a code review. Yes, that's also disallowed in D. > I should use %lld for long long, but the printf implementation shipped with the compiler doesn't support that. Weird that your compiler would support long long, but with a broken Standard library. I don't see that as a feature. You can always cast the argument to long, and at least you won't get undefined behavior.
    - 1718627440 10mo ago
      > Rewrite as: Could do that I just don't like the look. :-) > Have you ever discovered this bug: Actually no, because the coding style I use either puts it on a single line or with braces. I never indent just a single line. So: if (condition) doThis (); or: if (condition) { doThis (); } > Weird that your compiler would support long long, but with a broken Standard library. Yeah, for your information it was GCC combined with newlib for arm-none-eabi shipped with Debian/MS Windows.
      - WalterBright 10mo ago
        > So or Those are not what I was mentioning. It was the use of ; immediately following for(). No loop body.
        1718627440 10mo ago
        That was the answer to your: > Have you ever discovered this bug: [...]

WalterBright 10mo ago

Every switch that changes the language semantics creates a separate language. If you have n such switches, your compiler is supporting n x n languages. I've also had troubles writing portable C code with all warnings enabled as different compilers contradicted each other on what was acceptable. I tried pretty hard to make D a warning-less language, but still some crept in grump grump. Have fun with this one: for (int i = 0; i < end; ++i); foo(i); One of the best programmers I know came up to me with this loop and told me my C compiler was broken because the loop was only executed once. I pointed at the ; and you can guess the rest. I added a warning for that in the C compiler, and for D simply disallowed it. I've noticed that some C compilers have since added a warning for that as well. The C folks should just make it illegal. I've also fixed printf in D so that: char* p; printf("%d\n", p); gives an error message, and the right format to use for `p`. It was a little thing, but it sure found a lot of incorrect formats in my code.

1718627440 10mo ago
> The C folks should just make it illegal. I often have code, which looks like this: for (ptr = start; random_condition (*ptr); ptr = ptr->next); for (ptr = ptr->next; other_condition (*ptr); ptr = ptr->prev); ... [do action] for (ptr = end; to_be_deleted (*ptr) && (delete (ptr), TRUE); ptr = ptr->prev); I wouldn't be happy about your policy. > I've also fixed printf in D so that [...] gives an error message Just last week I had the case that the C compiler complained, I should use %lld for long long, but the printf implementation shipped with the compiler doesn't support that. Thus, using %ld, even if undefined behaviour was the correct action. I wouldn't like my language making up more work for me for no reason.
- WalterBright 10mo ago
  Rewrite as: for (ptr = start; random_condition (*ptr); ptr = ptr->next) { } Then anyone reading your code will know the empty loop was intentional. BTW, many C compilers warn about the ; on a for loop. Have you ever discovered this bug: if (condition); doThis(); It's a hard one to see in a code review. Yes, that's also disallowed in D. > I should use %lld for long long, but the printf implementation shipped with the compiler doesn't support that. Weird that your compiler would support long long, but with a broken Standard library. I don't see that as a feature. You can always cast the argument to long, and at least you won't get undefined behavior.
  - 1718627440 10mo ago
    > Rewrite as: Could do that I just don't like the look. :-) > Have you ever discovered this bug: Actually no, because the coding style I use either puts it on a single line or with braces. I never indent just a single line. So: if (condition) doThis (); or: if (condition) { doThis (); } > Weird that your compiler would support long long, but with a broken Standard library. Yeah, for your information it was GCC combined with newlib for arm-none-eabi shipped with Debian/MS Windows.
    - WalterBright 10mo ago
      > So or Those are not what I was mentioning. It was the use of ; immediately following for(). No loop body.
      - 1718627440 10mo ago
        That was the answer to your: > Have you ever discovered this bug: [...]