diff --git a/classes.c b/classes.c
index 2f3abf6..08c96b6 100644
--- a/classes.c
+++ b/classes.c
@@ -360,7 +360,7 @@ static uint64_t class__size(const struct class *self)
 	return size;
 }
 
-static const char *class__name(struct class *self, char *bf, size_t len)
+static const char *class__name(const struct class *self, char *bf, size_t len)
 {
 	if (self->tag.tag == DW_TAG_pointer_type) {
 		if (self->tag.type == 0) /* No type == void */
@@ -1022,7 +1022,7 @@ static int class__print_cacheline_boundary(uint32_t last_cacheline,
 	return cacheline;
 }
 
-static void class__print_struct(struct class *self)
+static void class__print_struct(const struct class *self)
 {
 	unsigned long sum = 0;
 	unsigned long sum_holes = 0;
@@ -1148,7 +1148,7 @@ static void class__print_struct(struct class *self)
 	putchar('\n');
 }
 
-void class__print(struct class *self)
+void class__print(const struct class *self)
 {
 	printf("/* %s:%u */\n", self->tag.decl_file, self->tag.decl_line);
 
diff --git a/classes.h b/classes.h
index 14dc02b..f0ce5dd 100644
--- a/classes.h
+++ b/classes.h
@@ -139,7 +139,7 @@ struct label {
 #define DEFAULT_CACHELINE_SIZE 32
 
 extern void class__find_holes(struct class *self);
-extern void class__print(struct class *self);
+extern void class__print(const struct class *self);
 extern void function__print(const struct function *self, int show_stats,
 			    const int show_variables,
 			    const int show_inline_expansions);