1 files changed, 1 insertions, 1 deletions
diff --git a/include/filetype.h b/include/filetype.h
index 91139dbfe3..502b920927 100644
--- a/include/filetype.h
+++ b/include/filetype.h
@@ -30,7 +30,7 @@ enum filetype {
 
 const char *file_type_to_string(enum filetype f);
 const char *file_type_to_short_string(enum filetype f);
-enum filetype file_detect_type(void *_buf, size_t bufsize);
+enum filetype file_detect_type(const void *_buf, size_t bufsize);
 enum filetype file_name_detect_type(const char *filename);
 enum filetype is_fat_or_mbr(const unsigned char *sector, unsigned long *bootsec);