Interesting bug hunt!

Got called in because a co-team had a strange bug and couldn't make sense of it. After a compiler update, things had stopped working.

They had already hunted down the bug to something equivalent to the screenshot and put a breakpoint on the if-statement. The memory window showed the memory content, and it was indeed 42. However, the debugger would still jump over do_stuff(), both in single step and when setting a breakpoint on the function call. Very unusual, but the rest worked.

Looking closer, I noticed that the pointer's content was an odd number, but was supposed to be of type uint32_t *. So I dug out the controller's manual and looked up the instruction set what it would do with a 32 bit load from an unaligned address: the most braindead thing possible, it would just ignore the lowest two address bits. So the actual load happened from a different address, that's why the comparison failed.

I think the debugger fetched the memory content bytewise because that would work for any kind of data structure with only one code path, that's how it bypassed the alignment issue. Nice pitfall!

Investigating further why the pointer was off, it turned out that it pointed into an underlying array of type char. The offset into the array was correctly divisible by 4, but the beginning had no alignment, and a char array doesn't need one. I checked the mapfiles and indeed, the old compiler had put the array to a 4 byte boundary and the new one didn't.

Sure enough, after giving the array a 4 byte alignment directive, the code worked as intended.

Mother fucking SQL, fuck mathematicians, fuck every thing!

So let's supose we'd only need the first char of a string. Every, and I mean fucking every (php, java, javascript, ruby, python, haskell) fucking language, uses something like `substring(input, 0, 1)` as it knows the input is nothing more than a fucking array of chars, otherwise known as motherfucking String. Logically the offset for the first char is 0.

Enter SQL, there you need to put `SUBSTRING(input, 1, 1)` because fuck every one! Fucking math guys who developed relational algebra on which (most) databases are based on (I love you for it, but come on you fuckers!), Decided that the first character should be at position 1...

Fuckers

University Coding Exam for Specialization Batch:
Q. Write a Program to merge two strings, each can be of at max 25k length.
Wrote the code in C, because fast.
Realized some edge cases don't pass, runtime errors. Proceed on to check the locked code in the Stub. (We only have to write methods, the driver code is pre-written)
Found that the memory for the char Arrays is being allocated dynamically with size 10240.
Rant #1:
Dafuq? What's the point of dynamic Memory Allocation if you're gonna fix it to a certain amount anyway?
Continuing...
Called the Program Incharge, asking him to check the problem and provide a solution. He took 10 minutes to come, meanwhile I wrote the program in Java which cleared all the test cases. <backstory>No University Course on Java yet, learnt it on my own </backstory>
Dude comes, I explain the problem. He asks me to do it in C++ instead coz it uses the string type instead of char array.
I told him that I've already done it in Java.
Him: Do you know Java?

Rant #2:
No you jackass! I did the whole thing in Java without knowing Java, what's wrong with you!

A c-style string is basically just a

Learning C and just wrote a function to reverse chars in a char array (ex. "Hello" -> "olleH") but the array did not change.

It took me way to long to realize: I forgot to divide the length variable by two. So it reversed the array back everytime...

C:
char greeting[] = "Hello world";

Developers: char array... What da f*CK!

C++
... Okay.

std::string,
std::string_view,
char*,
std::wstring,
hstring,
qstring...
How about now? ( ͡° ͜ʖ ͡°)

old MATLAB versions are such a pain

I can't even check if a char array (sort of a string) contains another char array.

MATLAB is like a sports car for mathematics, but a broken wheel chair for actual programming......

I don't know what's happening. In passing a char pointer to a function. I'm having issue, so I'm printf'ing the address pointed to by the pointer. Right after I assign it, it contains the right address, but the printf on the next line has it containing a different address. Another printf shows another different value, but all the following printfs show that third value. They're all consecutive printfs with nothing happening in between in the program, and the char* starts it's life as an array. All compiler optimizations are disabled. I don't know what's happening, it's just randomly changing. 😭