1 files changed, 1 insertions, 1 deletions

diff --git a/src/doprnt.c b/src/doprnt.c
index 16295389513..b88acf42118 100644
--- a/src/doprnt.c
+++ b/src/doprnt.c
@@ -111,7 +111,7 @@ doprnt1 (lispstrings, buffer, bufsize, format, format_end, nargs, args)
   char *fmtcpy;
   int minlen;
   int size;                     /* Field width factor; e.g., %90d */
-  char charbuf[5];              /* Used for %c.  */
+  unsigned char charbuf[5];     /* Used for %c.  */
 
   if (format_end == 0)
     format_end = format + strlen (format);