Arguments to ctype functions are required to be either EOF or representable

[u/mdw/putty] / logging.c

diff --git a/logging.c b/logging.c
index db02892..17924c5 100644 (file)
--- a/logging.c
+++ b/logging.c
@@ -384,7 +384,7 @@ static void xlatlognam(Filename *dest, Filename src,
            char c;
            s++;
            size = 0;
-           if (*s) switch (c = *s++, tolower(c)) {
+           if (*s) switch (c = *s++, tolower((unsigned char)c)) {
              case 'y':
                size = strftime(buf, sizeof(buf), "%Y", tm);
                break;