Maybe I wasn't clear in the explanation.

$#="%c";print 65; should not print an A. It pushes 65.0 (a double) and "%x" on the C stack, and calls sprintf. Then sprintf sees "%c", so tries to pop an int from the stack. 65.0 is represented as the bytes (00 00 00 00 00 40 50 40)hex, but an int is just 4 bytes so it pops (00 00 00 00)hex which is 0 as an int so it prints a nul char. (On sparc, however, it will get (40 50 40 00)hex, which is 67437568, so it will either print a null character or a multibyte character sequence corresponding to unicode chr 67437568, depending on the version of Perl.)

Dlugosz, I guess your cpu is an x86, correct me if it isn't.