3 ms·

Michał Zalewski's article on page 42 is very funny.

• mixedmath 2mo ago
  Would someone be interested in explaining what in the world is going on in that article?
  • q3k 2mo ago
    What do you mean? It's just simple beginner's examples in C. Should be easy enough to understand, C is famously very simple ('portable assembler' as they say!).
    • FergusArgyll 2mo ago
      > In our experience, C has proven to be a pleasant, expressive and versatile language for a wide variety of programs. It is easy to learn, and it wears well as one's experience with it grows. The C Programming Language K&R
  • pillmillipedes 2mo ago
    I'll try to do the first one since I think it's the most illustrative: 1 long typedef[[]]*($)(void*($),...); 2 int main() { 3 char* str = "Hello, world."; 4 $ $ asm("puts"); 5 $:&&$&&$(str); 6 } (1) is equivalent to "typedef long* $(void*, ...)". '$' is the name of the defined function type. it's obfuscated as follows: - typedef is a specifier and can go on either side of the type, same as int const/const int - [[ ]] is an empty list of attributes - "void*($)" is an argument named '$' of type void*, but parameter names are ignored in declarations. - you can put parens in declarations since sometimes you need to group prefixes and postfixes in a different order - dollar signs in names are allowed in many c compilers (and some other c-like languages) - "..." are variadic arguments. puts doesn't have those, but the first argument uses the same register either way so it happens to work out in this case (4) declares a function named '$' of type '$', shadowing the type, and links it to the assembly label "puts". calling $ calls puts. normally it looks like `int call_foo(void) asm("foo");` (5) is parsed as: "label $: address-of-label $ and function $ called on str. the address of a label is truthy, so the function also gets called. unary && looks for the argument in the label namespace, but other operators don't, so the two dollars refer to different things. that's about it. if you're familiar with the c standard and some common gnu extentions, you can deconstruct the examples into their basic elements easily enough