diff --git a/gio/gdbusdaemon.c b/gio/gdbusdaemon.c
index 2e67b5d67..3516183f9 100644
--- a/gio/gdbusdaemon.c
+++ b/gio/gdbusdaemon.c
@@ -204,7 +204,7 @@ name_lookup (GDBusDaemon *daemon, const char *str)
 }
 
 static gboolean
-is_key (const char *key_start, const char *key_end, char *value)
+is_key (const char *key_start, const char *key_end, const char *value)
 {
   gsize len = strlen (value);
 
@@ -1463,7 +1463,7 @@ filter_function (GDBusConnection *connection,
 		 gpointer         user_data)
 {
   Client *client = user_data;
-  char *types[] = {"invalid", "method_call", "method_return", "error", "signal" };
+  const char *types[] = {"invalid", "method_call", "method_return", "error", "signal" };
 
   if (0)
     g_printerr ("%s%s %s %d(%d) sender: %s destination: %s %s %s.%s\n",
diff --git a/gio/tests/file.c b/gio/tests/file.c
index 1519448ee..baf0bd745 100644
--- a/gio/tests/file.c
+++ b/gio/tests/file.c
@@ -153,9 +153,9 @@ typedef struct
   gint monitor_created;
   gint monitor_deleted;
   gint monitor_changed;
-  gchar *monitor_path;
+  const gchar *monitor_path;
   gint pos;
-  gchar *data;
+  const gchar *data;
   gchar *buffer;
   guint timeout;
 } CreateDeleteData;
diff --git a/gio/tests/fileattributematcher.c b/gio/tests/fileattributematcher.c
index 6956e6a36..553d57b19 100644
--- a/gio/tests/fileattributematcher.c
+++ b/gio/tests/fileattributematcher.c
@@ -3,7 +3,7 @@
 static void
 test_exact (void)
 {
-  char *exact_matches[] = {
+  const char *exact_matches[] = {
     "*",
     "a::*",
     "a::*,b::*",
@@ -29,8 +29,8 @@ static void
 test_equality (void)
 {
   struct {
-    char *expected;
-    char *actual;
+    const char *expected;
+    const char *actual;
   } equals[] = {
     /* star makes everything else go away */
     { "*", "*,*" },
@@ -70,9 +70,9 @@ static void
 test_subtract (void)
 {
   struct {
-    char *attributes;
-    char *subtract;
-    char *result;
+    const char *attributes;
+    const char *subtract;
+    const char *result;
   } subtractions[] = {
     /* * subtracts everything */
     { "*", "*", NULL },
diff --git a/gio/tests/gschema-compile.c b/gio/tests/gschema-compile.c
index 65f656c52..81ded83fa 100644
--- a/gio/tests/gschema-compile.c
+++ b/gio/tests/gschema-compile.c
@@ -22,17 +22,17 @@ test_schema_do_compile (gpointer data)
   SchemaTest *test = (SchemaTest *) data;
   gchar *filename = g_strconcat (test->name, ".gschema.xml", NULL);
   gchar *path = g_test_build_filename (G_TEST_DIST, "schema-tests", filename, NULL);
-  gchar *argv[] = {
+  const gchar *argv[] = {
     GLIB_COMPILE_SCHEMAS,
     "--strict",
     "--dry-run",
     "--schema-file", path,
-    (gchar *)test->opt,
+    test->opt,
     NULL
   };
   gchar *envp[] = { NULL };
 
-  execve (argv[0], argv, envp);
+  execve (argv[0], (char **) argv, envp);
   g_assert_not_reached ();
 }
 
diff --git a/gio/tests/pollable.c b/gio/tests/pollable.c
index c61525d09..826eaecad 100644
--- a/gio/tests/pollable.c
+++ b/gio/tests/pollable.c
@@ -61,7 +61,7 @@ check_source_readability_callback (gpointer user_data)
 static gboolean
 write_callback (gpointer user_data)
 {
-  char *buf = "x";
+  const char *buf = "x";
   gssize nwrote;
   GError *error = NULL;
 
diff --git a/gio/tests/simple-proxy.c b/gio/tests/simple-proxy.c
index 00bdb2ea4..f1eb6af9b 100644
--- a/gio/tests/simple-proxy.c
+++ b/gio/tests/simple-proxy.c
@@ -32,7 +32,7 @@ static void
 test_uris (void)
 {
   GProxyResolver *resolver;
-  gchar *ignore_hosts[2] = { "127.0.0.1", NULL };
+  const gchar *ignore_hosts[2] = { "127.0.0.1", NULL };
   gchar **proxies;
   GError *error = NULL;
   const gchar *uri;
@@ -41,7 +41,7 @@ test_uris (void)
 
   /* Valid URI. */
   uri = "http://%E0%B4%A8%E0%B4%B2:80/";
-  resolver = g_simple_proxy_resolver_new (NULL, ignore_hosts);
+  resolver = g_simple_proxy_resolver_new (NULL, (char **) ignore_hosts);
 
   proxies = g_proxy_resolver_lookup (resolver, uri, NULL, &error);
   g_assert_no_error (error);
@@ -60,7 +60,7 @@ test_uris (void)
   /* Invalid URI. */
   uri = "%E0%B4%A8%E0%B4%B2";
   str = g_strdup_printf ("Invalid URI ‘%s’", uri);
-  resolver = g_simple_proxy_resolver_new (NULL, ignore_hosts);
+  resolver = g_simple_proxy_resolver_new (NULL, (char **) ignore_hosts);
 
   proxies = g_proxy_resolver_lookup (resolver, uri, NULL, &error);
   g_assert_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT);
@@ -81,7 +81,7 @@ test_uris (void)
   g_object_unref (resolver);
   g_free (str);
 
-  resolver = g_simple_proxy_resolver_new ("default://", ignore_hosts);
+  resolver = g_simple_proxy_resolver_new ("default://", (char **) ignore_hosts);
   g_simple_proxy_resolver_set_uri_proxy (G_SIMPLE_PROXY_RESOLVER (resolver),
                                          "http", "http://proxy.example.com");
   g_simple_proxy_resolver_set_uri_proxy (G_SIMPLE_PROXY_RESOLVER (resolver),
@@ -136,11 +136,11 @@ static void
 test_socks (void)
 {
   GProxyResolver *resolver;
-  gchar *ignore_hosts[2] = { "127.0.0.1", NULL };
+  const gchar *ignore_hosts[2] = { "127.0.0.1", NULL };
   gchar **proxies;
   GError *error = NULL;
 
-  resolver = g_simple_proxy_resolver_new ("socks://proxy.example.com", ignore_hosts);
+  resolver = g_simple_proxy_resolver_new ("socks://proxy.example.com", (char **) ignore_hosts);
 
   proxies = g_proxy_resolver_lookup (resolver, "http://one.example.com/",
                                      NULL, &error);
@@ -160,7 +160,7 @@ test_socks (void)
 
   g_object_unref (resolver);
 
-  resolver = g_simple_proxy_resolver_new ("default-proxy://", ignore_hosts);
+  resolver = g_simple_proxy_resolver_new ("default-proxy://", (char **) ignore_hosts);
   g_simple_proxy_resolver_set_uri_proxy (G_SIMPLE_PROXY_RESOLVER (resolver),
                                          "http", "socks://proxy.example.com");
 
diff --git a/glib/gbacktrace.c b/glib/gbacktrace.c
index db2bf05d2..5300c6838 100644
--- a/glib/gbacktrace.c
+++ b/glib/gbacktrace.c
@@ -226,7 +226,7 @@ g_on_error_stack_trace (const gchar *prg_name)
 #if defined(G_OS_UNIX)
   pid_t pid;
   gchar buf[16];
-  gchar *args[4] = { "gdb", NULL, NULL, NULL };
+  const gchar *args[4] = { "gdb", NULL, NULL, NULL };
   int status;
 
   if (!prg_name)
@@ -234,7 +234,7 @@ g_on_error_stack_trace (const gchar *prg_name)
 
   _g_sprintf (buf, "%u", (guint) getpid ());
 
-  args[1] = (gchar*) prg_name;
+  args[1] = prg_name;
   args[2] = buf;
 
   pid = fork ();
diff --git a/glib/gcharset.c b/glib/gcharset.c
index 8aa549694..bfcd12590 100644
--- a/glib/gcharset.c
+++ b/glib/gcharset.c
@@ -235,8 +235,8 @@ g_get_codeset (void)
 
 /* read an alias file for the locales */
 static void
-read_aliases (gchar      *file,
-              GHashTable *alias_table)
+read_aliases (const gchar *file,
+              GHashTable  *alias_table)
 {
   FILE *fp;
   char buf[256];
diff --git a/glib/gdatetime.c b/glib/gdatetime.c
index 0820e0d8b..1bd916587 100644
--- a/glib/gdatetime.c
+++ b/glib/gdatetime.c
@@ -2767,11 +2767,11 @@ format_z (GString *outstr,
 }
 
 static void
-format_number (GString  *str,
-               gboolean  use_alt_digits,
-               gchar    *pad,
-               gint      width,
-               guint32   number)
+format_number (GString     *str,
+               gboolean     use_alt_digits,
+               const gchar *pad,
+               gint         width,
+               guint32      number)
 {
   const gchar *ascii_digits[10] = {
     "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"
@@ -2909,7 +2909,7 @@ g_date_time_format_locale (GDateTime   *datetime,
   gunichar  c;
   gboolean  alt_digits = FALSE;
   gboolean  pad_set = FALSE;
-  gchar    *pad = "";
+  const gchar *pad = "";
   const gchar *name;
   const gchar *tz;
 
diff --git a/glib/tests/convert.c b/glib/tests/convert.c
index 03c0d7209..5ffee6162 100644
--- a/glib/tests/convert.c
+++ b/glib/tests/convert.c
@@ -34,8 +34,8 @@
 static void
 test_iconv_state (void)
 {
-  gchar *in = "\xf4\xe5\xf8\xe5\xed";
-  gchar *expected = "\xd7\xa4\xd7\x95\xd7\xa8\xd7\x95\xd7\x9d";
+  const gchar *in = "\xf4\xe5\xf8\xe5\xed";
+  const gchar *expected = "\xd7\xa4\xd7\x95\xd7\xa8\xd7\x95\xd7\x9d";
   gchar *out;
   gsize bytes_read = 0;
   gsize bytes_written = 0;
@@ -107,7 +107,7 @@ test_byte_order (void)
 {
   gchar in_be[4] = { 0xfe, 0xff, 0x03, 0x93}; /* capital gamma */
   gchar in_le[4] = { 0xff, 0xfe, 0x93, 0x03};
-  gchar *expected = "\xce\x93";
+  const gchar *expected = "\xce\x93";
   gchar *out;
   gsize bytes_read = 0;
   gsize bytes_written = 0;
@@ -588,7 +588,7 @@ check_utf16_to_ucs4 (const gunichar2 *utf16,
 static void
 test_unicode_conversions (void)
 {
-  char *utf8;
+  const char *utf8;
   gunichar ucs4[100];
   gunichar2 utf16[100];
 
@@ -913,7 +913,7 @@ test_filename_from_utf8_embedded_nul_iconv (void)
 static void
 test_no_conv (void)
 {
-  gchar *in = "";
+  const gchar *in = "";
   gchar *out G_GNUC_UNUSED;
   gsize bytes_read = 0;
   gsize bytes_written = 0;