[PATCH] - improve sprintf buffer overflow detection (middle-end/49905)

Joseph Myers joseph@codesourcery.com
Wed Oct 5 16:27:00 GMT 2016

On Wed, 5 Oct 2016, Martin Sebor wrote:

> The warning would only helpful if there was a target where wchar_t
> didn't promote to a type with the same precision as wint_t, or in

Or it could show up a logical error where the code should have had a 
wint_t variable and checked for WEOF somewhere but just assumed things 
would fit in wchar_t (and so could be passing a negative value where the 
ABI means the callee expects wint_t values to be zero-extended, with 
consequent undefined behavior there).  The correct fix involves thinking 
about where you know something is a wide character, and where something 
might be a wide character or WEOF.  It might then involve a cast to 
wint_t, or changing the type of a variable, or more changes than that.

Joseph S. Myers

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