diff --git a/ext/zend_test/test.c b/ext/zend_test/test.c
index c27f46360e4..1dbefe5c687 100644
--- a/ext/zend_test/test.c
+++ b/ext/zend_test/test.c
@@ -1365,9 +1365,12 @@ PHP_ZEND_TEST_API int gh11934b_ffi_var_test_cdata;
 /**
  * This function allows us to simulate early return of copy_file_range by setting the limit_copy_file_range ini setting.
  */
-PHP_ZEND_TEST_API ssize_t copy_file_range(int fd_in, off_t *off_in, int fd_out, off_t *off_out, size_t len, unsigned int flags)
+#ifdef __MUSL__
+typedef off_t off64_t;
+#endif
+PHP_ZEND_TEST_API ssize_t copy_file_range(int fd_in, off64_t *off_in, int fd_out, off64_t *off_out, size_t len, unsigned int flags)
 {
-	ssize_t (*original_copy_file_range)(int, off_t *, int, off_t *, size_t, unsigned int) = dlsym(RTLD_NEXT, "copy_file_range");
+	ssize_t (*original_copy_file_range)(int, off64_t *, int, off64_t *, size_t, unsigned int) = dlsym(RTLD_NEXT, "copy_file_range");
 	if (ZT_G(limit_copy_file_range) >= Z_L(0)) {
 		len = ZT_G(limit_copy_file_range);
 	}