diff --git a/ext/exif/exif.c b/ext/exif/exif.c
index 72b16345bfc..77c95525764 100644
--- a/ext/exif/exif.c
+++ b/ext/exif/exif.c
@@ -2536,7 +2536,7 @@ static int exif_process_undefined(char **result, char *value, size_t byte_count
 
 /* {{{ exif_process_string_raw
  * Copy a string in Exif header to a character string returns length of allocated buffer if any. */
-#ifndef EXIF_USE_MBSTRING
+#if !EXIF_USE_MBSTRING
 static int exif_process_string_raw(char **result, char *value, size_t byte_count) {
 	/* we cannot use strlcpy - here the problem is that we have to copy NUL
 	 * chars up to byte_count, we also have to add a single NUL character to