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No. I don't know how Haskell fans feel about it, but I don't see anything wrong with it if it works and lets you write more good code than you would writing everything in C. C isn't that scary.



C isn't that sca... Segmentation fault


I've never understood why people always seem to immediately bring up segfaults as scary C behavior. Is it really that different than Python dying with "AttributeError: 'NoneType' object has no attribute 'foo'", or a NullPointerException in Java? Sure, in the latter two you get a stack trace, but you can rig up C to give you that too if you want.

What's actually potentially scary in C is code that doesn't segfault, but just continues running along with silently-corrupted memory. (And that's something that doesn't have an analogous failure mode in most other languages, as far as I know.)


Yes it's actually really different because the error is non-specific (unhelpful) and can be caused by a completely unrelated operation, so debugging is harder.


  $ gdb myprog myprog.core
  % backtrace full
  ...[stack frames with program line numbers printed here...]

Edit: formatting


Indeed, but that backtrace can be completely unrelated to what caused the memory corruption, so it's definitely more difficult than with managed languages, which was the point I made.


And the AttributeError can be completely unrelated to what set a variable to something of the wrong type, so it's definitely not dissimilar to C's memory corruption.

The kind of errors that scare me are silently writing past the end of an array on the stack, which will silently introduce wrong values that will probably not crash your program.


The AttributeError is in a different category, because the interpreter protects you from doing unsafe things, and you get a clue as to what is wrong because you get the name of an attribute and the object which was supposed to have it. Segmentation faults can be much more difficult. For example the other day I got a segmentation fault deep in the CPython code; there was no bug there, and moving up the stack trace also did not reveal a bug either. It turned out that I had messed up a reference count _in a completely different (Cython compiled) module_, and I only found out after poring over several sections of code repeatedly.

The reason that this can happen in C is actually exactly what you bring up, silently corrupting memory. It's just that with the segmentation fault the silence is broken abruptly.


That is what Valgrind / LLVM memory sanitizer are for


We can't know how much data was destroyed between the truncation of the message and the actual segfault message...


Segfaults are just the most user-visible consequence of lack of memory safety.


You can't have everything at once




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