diff --git a/lib/mcconfig.h b/lib/mcconfig.h
index 5452b25d8..ff3abced2 100644
--- a/lib/mcconfig.h
+++ b/lib/mcconfig.h
@@ -31,7 +31,7 @@ void mc_config_deinit (mc_config_t *);
 gboolean mc_config_del_key (mc_config_t *, const char *, const gchar *);
 gboolean mc_config_del_group (mc_config_t *, const char *);
 
-gboolean mc_config_has_param (mc_config_t *, const char *, const gchar *);
+gboolean mc_config_has_param (const mc_config_t *, const char *, const gchar *);
 gboolean mc_config_has_group (mc_config_t *, const char *);
 
 gboolean mc_config_read_file (mc_config_t * mc_config, const gchar * ini_path,
@@ -44,13 +44,13 @@ gboolean mc_config_save_to_file (mc_config_t * config, const gchar * filename, G
 
 /* mcconfig/get.c: */
 
-gchar **mc_config_get_groups (mc_config_t *, gsize *);
+gchar **mc_config_get_groups (const mc_config_t *, gsize *);
 
-gchar **mc_config_get_keys (mc_config_t *, const gchar *, gsize *);
+gchar **mc_config_get_keys (const mc_config_t *, const gchar *, gsize *);
 
 gchar *mc_config_get_string (mc_config_t *, const gchar *, const gchar *, const gchar *);
 
-gchar *mc_config_get_string_raw (mc_config_t *, const gchar *, const gchar *, const gchar *);
+gchar *mc_config_get_string_raw (const mc_config_t *, const gchar *, const gchar *, const gchar *);
 
 gboolean mc_config_get_bool (mc_config_t *, const gchar *, const gchar *, gboolean);
 
@@ -68,7 +68,7 @@ int *mc_config_get_int_list (mc_config_t *, const gchar *, const gchar *, gsize
 
 void mc_config_set_string_raw (mc_config_t *, const gchar *, const gchar *, const gchar *);
 
-void mc_config_set_string (mc_config_t *, const gchar *, const gchar *, const gchar *);
+void mc_config_set_string (const mc_config_t *, const gchar *, const gchar *, const gchar *);
 
 void mc_config_set_bool (mc_config_t *, const gchar *, const gchar *, gboolean);
 
diff --git a/lib/mcconfig/common.c b/lib/mcconfig/common.c
index 51866fe7c..bb5ee98de 100644
--- a/lib/mcconfig/common.c
+++ b/lib/mcconfig/common.c
@@ -137,7 +137,7 @@ mc_config_deinit (mc_config_t * mc_config)
 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 gboolean
-mc_config_has_param (mc_config_t * mc_config, const char *group, const gchar * param)
+mc_config_has_param (const mc_config_t * mc_config, const char *group, const gchar * param)
 {
     if (!mc_config || !group || !param)
         return FALSE;
diff --git a/lib/mcconfig/get.c b/lib/mcconfig/get.c
index e3ced7cac..6a5e11afc 100644
--- a/lib/mcconfig/get.c
+++ b/lib/mcconfig/get.c
@@ -36,7 +36,7 @@
 /*** public functions **************************************************/
 
 gchar **
-mc_config_get_groups (mc_config_t * mc_config, gsize * len)
+mc_config_get_groups (const mc_config_t * mc_config, gsize * len)
 {
     gchar **ret;
 
@@ -58,7 +58,7 @@ mc_config_get_groups (mc_config_t * mc_config, gsize * len)
 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 gchar **
-mc_config_get_keys (mc_config_t * mc_config, const gchar * group, gsize * len)
+mc_config_get_keys (const mc_config_t * mc_config, const gchar * group, gsize * len)
 {
     gchar **ret;
 
@@ -126,7 +126,7 @@ mc_config_get_string (mc_config_t * mc_config, const gchar * group,
 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 gchar *
-mc_config_get_string_raw (mc_config_t * mc_config, const gchar * group,
+mc_config_get_string_raw (const mc_config_t * mc_config, const gchar * group,
                           const gchar * param, const gchar * def)
 {
     gchar *ret;
diff --git a/lib/mcconfig/set.c b/lib/mcconfig/set.c
index 5df9b19ba..dc71e9d6f 100644
--- a/lib/mcconfig/set.c
+++ b/lib/mcconfig/set.c
@@ -76,7 +76,7 @@ mc_config_set_string_raw (mc_config_t * mc_config, const gchar * group,
 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 void
-mc_config_set_string (mc_config_t * mc_config, const gchar * group,
+mc_config_set_string (const mc_config_t * mc_config, const gchar * group,
                       const gchar * param, const gchar * value)
 {
     gchar *buffer;