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by blackpill0w 1129 days ago
>C doesn't have this problem

I don't think a strong type system is a `problem`, implicit conversions can lead to so many annoying and hard to find bugs.
3 comments
ori_b 1129 days ago
That's a fine general sentiment. However, in this context it's a problem if you want to assign NULL to a pointer without a cast, which is why C++ added the magically convertible nullptr in addition to the magically convertible `0` constant.

     char *x = 0; // ok in C and C++
     char *y = (void*)0; // ok in C, error in C++
     char *z = nullptr; // ok in C++
therefore:

     #define NULL ((void*)0) // Required by Posix C, invalid C++
     #define NULL 0 // Pre-nullptr, the only valid C++ definition
C++ can't define NULL the safe way that Posix C does.

I don't understand why it's more acceptable to allow magic `0` conversions than magic `(void*)0` conversions, given that the latter is far less likely to happen by accident -- but here we are.

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rightbyte 1129 days ago
> I don't understand why it's more acceptable to allow magic `0` conversions than magic `(void*)0` conversions

In the end you don't have to chose between '0' and 'nullptr' anyways.

    char *x = (decltype (nullptr)) 0;
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Dylan16807 1129 days ago
They didn't say the type system is a problem, they said it caused a problem.
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kzrdude 1129 days ago
Case in point, integer arithmetic in C. Reasoning about types there is just tiring.
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