Arthur Krewat <krewat(a)kilonet.net> writes on Mon, 6 Nov 2017 19:34:34 -0500 I decided last night to investigate that statement, and updated my C/C++ features tool to test the sign and range of char and wchar_t. I ran it in our test lab with physical and virtual machines representing many different GNU/Hurd, GNU/Linux, *BSD, macOS, Minix, Solaris, and other Unix family members, on ARM, MIPS, PowerPC, SPARC, x86, and x86-64 CPU architectures. Here is a summary: % cat *.log | grep '^ char type is' | sort | uniq -c 157 char type is signed 3 char type is unsigned The sole outliers are * Arch Linux ARM on armv7l * IBM CentOS Linux release 7.4.1708 on PowerPC-8 * SGI IRIX 6.5 on MIPS R10000-SC for which I found these log data: Character range and sign... CHAR_MIN = +0 CHAR_MAX = +255 SCHAR_MIN = -128 SCHAR_MAX = +127 UCHAR_MAX = +255 char type is unsigned signed char type is signed unsigned char type is unsigned The last two lines are expected, but my program checked for an incorrect result, and would have produced the string "WRONG!" in the output; no system had that result. ------------------------------------------------------------------------------- - Nelson H. F. Beebe Tel: +1 801 581 5254 - - University of Utah FAX: +1 801 581 4148 - - Department of Mathematics, 110 LCB Internet e-mail: beebe(a)math.utah.edu - - 155 S 1400 E RM 233 beebe(a)acm.org beebe(a)computer.org - - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ - -------------------------------------------------------------------------------