options: simplify somewhat by introducing a union for option values

The m_option_value union is supposed to contain a field for each
possible option type (as long as it actually stores data). This helps
avoiding silly temporary memory alocations. Using a pointer to an union
and to a field of the union interchangeably should be allowed by
standard C.

1 files changed, 5 insertions, 6 deletions

diff --git a/m_config.c b/m_config.c
index ae7f528060..11272766d2 100644
--- a/m_config.c
+++ b/m_config.c
@@ -334,15 +334,14 @@ static void m_config_add_option(struct m_config *config,
             } else if (arg->type->flags & M_OPT_TYPE_DYNAMIC) {
                 // Initialize dynamically managed fields from static data (like
                 // string options): copy the option into temporary memory,
-                // clear the original option (to void m_option freeing the
+                // clear the original option (to stop m_option from freeing the
                 // static data), copy it back.
                 if (co->data) {
-                    void *temp = talloc_zero_size(NULL, arg->type->size);
-                    m_option_copy(arg, temp, co->data);
+                    union m_option_value temp = {0};
+                    m_option_copy(arg, &temp, co->data);
                     memset(co->data, 0, arg->type->size);
-                    m_option_copy(arg, co->data, temp);
-                    m_option_free(arg, temp);
-                    talloc_free(temp);
+                    m_option_copy(arg, co->data, &temp);
+                    m_option_free(arg, &temp);
                 }
             }
         }