SCANF function only records first letter pressed

Question

I am working on a simple OS in C++, and am trying to implement the keyboard without using interrupts (yes I'm being lazy-) however the char* returned by the function only has one letter (the first one pressed) It uses a variable called MAX_16, which is simply 2^16 I'm making my own STDLIB and don't have access to most STDLIB functions.

char* scanf() {
    char* ret;
    for(int i = 0; i <= max_16; i++) {
        ret[i] = getkey();
        if(ret[i] == '\n') { return ret; }
    }
}

It collects keypresses using inb(0x60); – Ramdomly Random Jul 28 '21 at 08:21 — Ramdomly Random, Jul 28 '21 at 08:21

score 1 · Answer 1 · answered Aug 05 '21 at 19:52

1

ret is never initialized, so inside the loop, you are continually writing to garbage memory. Likely a fault is being triggered which causes the application to hang, causing no more input to be processed.

answered Aug 05 '21 at 19:52

brenden

574
3
16

So simply add `char* ret = new char();`? – Ramdomly Random Aug 05 '21 at 21:13

SCANF function only records first letter pressed

1 Answers1