Convert char to unsigned char before using islower/toupper.

Failure to do so is undefined behaviour for any negative char values.

diff --git a/src/microcode/findprim.c b/src/microcode/findprim.c
index f85f5e23277c1265b8082deeee3fdeeafc70ce01..93eb3c162ca8852e39332206de939caf18726e96 100644 (file)
--- a/src/microcode/findprim.c
+++ b/src/microcode/findprim.c
@@ -1206,8 +1206,8 @@ strcmp_ci (const char * s1, const char * s2)
 
   while ((length--) > 0)
     {
-      int c1 = (*s1++);
-      int c2 = (*s2++);
+      int c1 = ((unsigned char) (*s1++));
+      int c2 = ((unsigned char) (*s2++));
       if (islower (c1)) c1 = (toupper (c1));
       if (islower (c2)) c2 = (toupper (c2));
       if (c1 < c2) return (-1);