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Comment by lifthrasiir | Hacker News Reader

> As the article says, checked exceptions are not the solution here.

Java had a very bad model of checked exceptions (the OP was written in 2008). A correct way is to make it a part of the type system, though it doesn't have to be a sum type like Rust, and make any error-related code path as convenient as possible to use.

> In C, you are forced to perform the NULL-check, or crash.

You don't necessarily crash if you failed to perform a NULL check! That's literally the single biggest problem with C's undefined behaviors. C looks like forcing checks only because most programmers do understand crashes are bad, so they do prepare for trivial or demonstrated crashes. But that's not guaranteed, and they can't easily prepare for non-crash failures without additional tools.

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> You don't necessarily crash if you failed to perform a NULL check!

In the case of using the result from `fopen`, I don't know of a platform where a dereferencing of NULL (which happens in a separate translation unit, which is already compiled and linked, and will not be subject to LTO and other optimisations) within the various read/write/seek/tell functions doesn't result in an immediate crash.

I fully admit that this is applicable only to this particular example, and to all the functions in the stdlib. Everywhere else (code you wrote, that will be subject to aggressive optimisation, for example), you may not necessarily crash on a NULL dereference.

In the sense of instilling a sense of paranoia, the relative frequency of crashing due to UB is high enough that it does develop the sense of paranoia.

That's a really huge asterisk that wasn't present in your original claim ;-)

> In the sense of instilling a sense of paranoia, the relative frequency of crashing due to UB is high enough that it does develop the sense of paranoia.

Paranoia isn't a cure however. A good programmer will and arguably should develop an instinct to avoid C for most cases instead. I too have written tons of C codes, and yet I feel really uneasy about using C at all. I can't believe that C merely induces the sense of paranoia.

> I don't know of a platform where a dereferencing of NULL (which happens in a separate translation unit, which is already compiled and linked, and will not be subject to LTO and other optimisations) within the various read/write/seek/tell functions doesn't result in an immediate crash.

Although in a very different content, I have seen "dereferencing" a null pointer in C++ not crash immediately, if you dereference it to call a nonvirtual class member function, e.g,

    t->foo();

Depending on how this gets compiled and the implementation of `foo()`, the segfault may not come at the line above, where technically `t` is being dereferenced. It may come inside `foo`, or somewhere further down the call chain. The resulting crash may not even manifest as a segfault.

> Although in a very different content, I have seen "dereferencing" a null pointer in C++ not crash immediately,

I don't think this is possible at all in C, which doesn't have classes, and the sophisticated following of pointers to find a method.

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