diff -r 897d8b86deae tools/libxl/xl_cmdimpl.c --- a/tools/libxl/xl_cmdimpl.c Tue May 25 10:01:18 2010 +0200 +++ b/tools/libxl/xl_cmdimpl.c Tue May 25 11:32:49 2010 +0200 @@ -1226,7 +1226,7 @@ static int64_t parse_mem_size_kb(char *m if (strlen(endptr) > 1) return -1; - switch (tolower(*endptr)) { + switch (tolower((uint8_t)*endptr)) { case 't': kbytes <<= 10; case 'g':