Why isn't this crashing?

[limpid pebble]

Hello, I just switched to Linux and am trying to learn how to switch from VS to VSCode. I want to see what happens when code crashes to see if I can explore the stack and variables like I can on Windows... but i just discovered that this code doesn't crash. Can anyone help me to understand why?

[lapis reef]

When your question is answered use !solved to mark the question as resolved.

Remember to ask specific questions, provide necessary details, and reduce your question to its simplest form. For tips on how to ask a good question use !howto ask.

[limpid pebble]

if i don't push_back anything into vec, then it does segfault as expected

however if I put two items into vec, then try to write to vec[4] and even read from vec[4] it doesn't crash!

and the output is: vec[4] is: 4

hmm, my kagi searching has led me to this: https://stackoverflow.com/questions/6452959/why-doesnt-my-program-crash-when-i-write-past-the-end-of-an-array

however I'm pretty sure on Windows that code would have crashed, would'nt it have?

[wet fractal]

Crashing is just one possibe outcome of UB.

[limpid pebble]

on windows in debug mode, I'm pretty sure that would have been caught though

i would love to use visual studio but I can't do that on linux

how can I get that safety back for debug mode?

well i found literally my question - https://stackoverflow.com/questions/76895047/how-to-make-vectors-do-bound-checking-in-vs-code

[wet fractal]

Well using at is the best you can do.

[mental girder]

you specify -D_GLIBCXX_DEBUG when compiling the code

[limpid pebble]

I’m not sure how to do that with vscode, I’ll try to figure it out. Thank you

[mental girder]

well, how do you compile the code?

https://code.visualstudio.com/docs/cpp/config-linux

[lapis reef]

@limpid pebble Has your question been resolved? If so, type !solved :)

[limpid pebble]

i just click this:

i guess i'll have to dig into the options and see where all that is defined