On 29/08/15 17:44, hyc@symas.com wrote:

This patch is incorrect. You must guard toupper(), it is not guaranteed not to distort non-lowercase characters.

Yes it is - for values in the range of unsigned char and EOF. Behavior is undefined for other values. The bug is failing to cast a char arguments to <ctype.h> functions to unsigned char.

It's a common bug, so some implementations support char args. They cannot support that fully for (char)EOF, though.

if (islower(x)) x = toupper(x)

That might hide the bug at times, maybe that's why you use it. But it's not reliable, islower too expects EOF or unsigned char. Use x = toupper((unsigned char)x).