2 files changed, 2 insertions, 2 deletions
diff --git a/elisp.c b/elisp.c
index bf08fbd..83ff7df 100644
--- a/elisp.c
+++ b/elisp.c
@@ -79,7 +79,7 @@ emacs_value symbol_value(emacs_env *env, emacs_value symbol) {
   return env->funcall(env, Fsymbol_value, 1, (emacs_value[]){symbol});
 }
 
-int string_bytes(emacs_env *env, emacs_value string) {
+ptrdiff_t string_bytes(emacs_env *env, emacs_value string) {
   ptrdiff_t size = 0;
   env->copy_string_contents(env, string, NULL, &size);
   return size;
diff --git a/elisp.h b/elisp.h
index ba5e5fe..e6a7eb9 100644
--- a/elisp.h
+++ b/elisp.h
@@ -65,7 +65,7 @@ extern emacs_value Fvterm_set_selection;
 void bind_function(emacs_env *env, const char *name, emacs_value Sfun);
 void provide(emacs_env *env, const char *feature);
 emacs_value symbol_value(emacs_env *env, emacs_value symbol);
-int string_bytes(emacs_env *env, emacs_value string);
+ptrdiff_t string_bytes(emacs_env *env, emacs_value string);
 emacs_value length(emacs_env *env, emacs_value string);
 emacs_value list(emacs_env *env, emacs_value elements[], ptrdiff_t len);
 emacs_value nth(emacs_env *env, int idx, emacs_value list);