diff --git a/minitar.h b/minitar.h
index 1d636ab..34a49fc 100644
--- a/minitar.h
+++ b/minitar.h
@@ -51,7 +51,7 @@ extern "C"
     int minitar_find_by_name(struct minitar* mp, const char* name, struct minitar_entry* out);
     int minitar_find_by_path(struct minitar* mp, const char* path, struct minitar_entry* out);
     int minitar_find_any_of(struct minitar* mp, enum minitar_file_type type, struct minitar_entry* out);
-    size_t minitar_read_contents(struct minitar* mp, struct minitar_entry* entry, char* buf, size_t max);
+    size_t minitar_read_contents(struct minitar* mp, const struct minitar_entry* entry, char* buf, size_t max);
     int minitar_close(struct minitar* mp);
 
 #ifdef __cplusplus
diff --git a/src/tar.c b/src/tar.c
index a5b6570..1242e82 100644
--- a/src/tar.c
+++ b/src/tar.c
@@ -111,7 +111,7 @@ int minitar_find_any_of(struct minitar* mp, enum minitar_file_type type, struct
     return -1;
 }
 
-size_t minitar_read_contents(struct minitar* mp, struct minitar_entry* entry, char* buf, size_t max)
+size_t minitar_read_contents(struct minitar* mp, const struct minitar_entry* entry, char* buf, size_t max)
 {
     if (!max) return 0;
     if (!entry->metadata.size) return 0;