mpaland/printf

printf("%s", NULL) - crash

mad-rain opened this issue · 4 comments

mad-rain commented

Hi!

Some placeholder should be used for NULL %s argument to prevent printf from crash:

      case 's' : {
        const char* p = va_arg(va, char*);
        if (!p) p = "(null)"; // please add this
noomio commented

I just came here to add just that!

    const char* p = va_arg(va, char*);
    p = (p == NULL) ? "(null)" : p;
  • 👍2
dev-zzo commented

This should be an optional behaviour as in many embedded situations address zero is a perfectly valid one.

  • 👍2
eyalroz commented

@dev-zzo : What about %p, then? Should that also not have an option to print 0 as 0 rather than (nil) on such platforms?

eyalroz commented

So, this issue is now fixed on my fork. @dev-zzo , @noomio , @mpaland Please have a look and voice your opinion about the behavior with null/0 pointers.

Also, @mpaland : Can you explain the code's "partiality" to the use of _out_rev? That is, what's the benefit of printing characters backwards like that? I used it too in the changes I made for this issue, but I was just following the pattern.