diff --git a/streaming.c b/streaming.c
index 7e7ee2be6..3a3cd1206 100644
--- a/streaming.c
+++ b/streaming.c
@@ -99,7 +99,7 @@ int close_istream(struct git_istream *st)
 	return r;
 }
 
-ssize_t read_istream(struct git_istream *st, char *buf, size_t sz)
+ssize_t read_istream(struct git_istream *st, void *buf, size_t sz)
 {
 	return st->vtbl->read(st, buf, sz);
 }
diff --git a/streaming.h b/streaming.h
index 3e827709c..1d05c2a46 100644
--- a/streaming.h
+++ b/streaming.h
@@ -10,7 +10,7 @@ struct git_istream;
 
 extern struct git_istream *open_istream(const unsigned char *, enum object_type *, unsigned long *, struct stream_filter *);
 extern int close_istream(struct git_istream *);
-extern ssize_t read_istream(struct git_istream *, char *, size_t);
+extern ssize_t read_istream(struct git_istream *, void *, size_t);
 
 extern int stream_blob_to_fd(int fd, const unsigned char *, struct stream_filter *, int can_seek);