Add -Wwrite-strings

and fix its warnings

41 files changed, 112 insertions, 110 deletions

diff --git a/configure.ac b/configure.ac
index a79c17874..6a9fb04ca 100644
--- a/configure.ac
+++ b/configure.ac
@@ -240,11 +240,13 @@ AG_GST_SET_PLUGINDIR
 
 dnl define an ERROR_CFLAGS Makefile variable
 AG_GST_SET_ERROR_CFLAGS($GST_GIT, [
-    -Wmissing-declarations -Wmissing-prototypes -Wredundant-decls -Wundef ])
+    -Wmissing-declarations -Wmissing-prototypes -Wredundant-decls -Wundef
+    -Wwrite-strings ])
 
 dnl define an ERROR_CXXFLAGS Makefile variable
 AG_GST_SET_ERROR_CXXFLAGS($GST_GIT, [
-    -Wmissing-declarations -Wredundant-decls -Wundef ])
+    -Wmissing-declarations -Wredundant-decls -Wundef
+    -Wwrite-strings ])
 
 dnl define correct level for debugging messages
 AG_GST_SET_LEVEL_DEFAULT($GST_GIT)
diff --git a/ext/cdaudio/gstcdaudio.c b/ext/cdaudio/gstcdaudio.c
index 4eb113f02..6e1dc4e06 100644
--- a/ext/cdaudio/gstcdaudio.c
+++ b/ext/cdaudio/gstcdaudio.c
@@ -589,7 +589,7 @@ cdaudio_uri_get_type (void)
 static gchar **
 cdaudio_uri_get_protocols (void)
 {
-  static gchar *protocols[] = { "cd", NULL };
+  static gchar *protocols[] = { (char *) "cd", NULL };
 
   return protocols;
 }
diff --git a/ext/directfb/dfbvideosink.c b/ext/directfb/dfbvideosink.c
index f6d2617d0..39862f414 100644
--- a/ext/directfb/dfbvideosink.c
+++ b/ext/directfb/dfbvideosink.c
@@ -574,7 +574,7 @@ gst_dfbvideosink_setup (GstDfbVideoSink * dfbvideosink)
         "DirectFB fullscreen");
     if (!dfbvideosink->dfb) {
       DFBGraphicsDeviceDescription hw_caps;
-      char *argv[] = { "-", "--dfb:quiet", NULL };
+      char *argv[] = { (char *) "-", (char *) "--dfb:quiet", NULL };
       int argc = 2;
       char **args;
 
@@ -667,16 +667,16 @@ gst_dfbvideosink_setup (GstDfbVideoSink * dfbvideosink)
 
       /* Check that this layer is able to do colorbalance settings */
       if (dl_desc.caps & DLCAPS_BRIGHTNESS) {
-        channels_list = g_list_append (channels_list, "BRIGHTNESS");
+        channels_list = g_list_append (channels_list, (char *) "BRIGHTNESS");
       }
       if (dl_desc.caps & DLCAPS_CONTRAST) {
-        channels_list = g_list_append (channels_list, "CONTRAST");
+        channels_list = g_list_append (channels_list, (char *) "CONTRAST");
       }
       if (dl_desc.caps & DLCAPS_HUE) {
-        channels_list = g_list_append (channels_list, "HUE");
+        channels_list = g_list_append (channels_list, (char *) "HUE");
       }
       if (dl_desc.caps & DLCAPS_SATURATION) {
-        channels_list = g_list_append (channels_list, "SATURATION");
+        channels_list = g_list_append (channels_list, (char *) "SATURATION");
       }
 
       if (channels_list) {
diff --git a/ext/jp2k/gstjasperdec.c b/ext/jp2k/gstjasperdec.c
index 61ba18d2c..05c1963ac 100644
--- a/ext/jp2k/gstjasperdec.c
+++ b/ext/jp2k/gstjasperdec.c
@@ -218,7 +218,7 @@ gst_jasper_dec_sink_setcaps (GstPad * pad, GstCaps * caps)
         break;
     }
 
-    dec->fmt = jas_image_strtofmt ("jpc");
+    dec->fmt = jas_image_strtofmt ((char *) "jpc");
     /* strip the j2c box stuff it is embedded in */
     if (!strcmp (mimetype, "image/x-jpc"))
       dec->strip = 0;
@@ -231,7 +231,7 @@ gst_jasper_dec_sink_setcaps (GstPad * pad, GstCaps * caps)
       gst_buffer_ref (dec->codec_data);
     }
   } else if (!strcmp (mimetype, "image/jp2"))
-    dec->fmt = jas_image_strtofmt ("jp2");
+    dec->fmt = jas_image_strtofmt ((char *) "jp2");
 
   if (dec->fmt < 0)
     goto refuse_caps;
@@ -457,7 +457,7 @@ gst_jasper_dec_get_picture (GstJasperDec * dec, guint8 * data,
   if (!(stream = jas_stream_memopen ((gpointer) data, size)))
     goto fail_stream;
 
-  if (!(image = jas_image_decode (stream, dec->fmt, "")))
+  if (!(image = jas_image_decode (stream, dec->fmt, (char *) "")))
     goto fail_decode;
 
   if (!gst_jasper_dec_negotiate (dec, image))
diff --git a/ext/jp2k/gstjasperenc.c b/ext/jp2k/gstjasperenc.c
index 7c923a413..92038f50e 100644
--- a/ext/jp2k/gstjasperenc.c
+++ b/ext/jp2k/gstjasperenc.c
@@ -255,10 +255,10 @@ gst_jasper_enc_init_encoder (GstJasperEnc * enc)
   switch (enc->mode) {
     case GST_JP2ENC_MODE_J2C:
     case GST_JP2ENC_MODE_JPC:
-      enc->fmt = jas_image_strtofmt ("jpc");
+      enc->fmt = jas_image_strtofmt ((char *) "jpc");
       break;
     case GST_JP2ENC_MODE_JP2:
-      enc->fmt = jas_image_strtofmt ("jp2");
+      enc->fmt = jas_image_strtofmt ((char *) "jp2");
       break;
   }
 
@@ -422,7 +422,7 @@ gst_jasper_enc_get_data (GstJasperEnc * enc, guint8 * data, GstBuffer ** outbuf)
 
   GST_LOG_OBJECT (enc, "all components written");
 
-  if (jas_image_encode (enc->image, stream, enc->fmt, ""))
+  if (jas_image_encode (enc->image, stream, enc->fmt, (char *) ""))
     goto fail_encode;
 
   GST_LOG_OBJECT (enc, "image encoded");
diff --git a/ext/libmms/gstmms.c b/ext/libmms/gstmms.c
index cbaa8e799..86df5ee94 100644
--- a/ext/libmms/gstmms.c
+++ b/ext/libmms/gstmms.c
@@ -561,9 +561,9 @@ gst_mms_uri_get_type (void)
 static gchar **
 gst_mms_uri_get_protocols (void)
 {
-  static gchar *protocols[] = { "mms", "mmsh", "mmst", "mmsu", NULL };
+  static const gchar *protocols[] = { "mms", "mmsh", "mmst", "mmsu", NULL };
 
-  return protocols;
+  return (gchar **) protocols;
 }
 
 static const gchar *
diff --git a/ext/metadata/gstbasemetadata.c b/ext/metadata/gstbasemetadata.c
index 6f13851ae..28579313f 100644
--- a/ext/metadata/gstbasemetadata.c
+++ b/ext/metadata/gstbasemetadata.c
@@ -322,7 +322,7 @@ gst_base_metadata_dispose_members (GstBaseMetadata * filter)
 const gchar *
 gst_base_metadata_get_type_name (int img_type)
 {
-  gchar *type_name = NULL;
+  const gchar *type_name = NULL;
 
   switch (img_type) {
     case IMG_JPEG:
@@ -412,7 +412,7 @@ gst_base_metadata_configure_caps (GstBaseMetadata * filter)
 {
   GstCaps *caps = NULL;
   gboolean ret = FALSE;
-  gchar *mime = NULL;
+  const gchar *mime = NULL;
   GstPad *peer = NULL;
 
   peer = gst_pad_get_peer (filter->sinkpad);
diff --git a/ext/metadata/gstmetadatademux.c b/ext/metadata/gstmetadatademux.c
index a4d485e9c..bb1080f0d 100644
--- a/ext/metadata/gstmetadatademux.c
+++ b/ext/metadata/gstmetadatademux.c
@@ -201,7 +201,7 @@ gst_metadata_demux_configure_srccaps (GstMetadataDemux * filter)
 {
   GstCaps *caps = NULL;
   gboolean ret = FALSE;
-  gchar *mime = NULL;
+  const gchar *mime = NULL;
 
   switch (GST_BASE_METADATA_IMG_TYPE (filter)) {
     case IMG_JPEG:
diff --git a/ext/metadata/gstmetadatamux.c b/ext/metadata/gstmetadatamux.c
index 61d2b4f9d..df8ff1cc4 100644
--- a/ext/metadata/gstmetadatamux.c
+++ b/ext/metadata/gstmetadatamux.c
@@ -195,7 +195,7 @@ gst_metadata_mux_configure_srccaps (GstMetadataMux * filter)
 {
   GstCaps *caps = NULL;
   gboolean ret = FALSE;
-  gchar *mime = NULL;
+  const gchar *mime = NULL;
 
   switch (GST_BASE_METADATA_IMG_TYPE (filter)) {
     case IMG_JPEG:
diff --git a/ext/mythtv/gstmythtvsrc.c b/ext/mythtv/gstmythtvsrc.c
index c80bae86d..1afc01ea5 100644
--- a/ext/mythtv/gstmythtvsrc.c
+++ b/ext/mythtv/gstmythtvsrc.c
@@ -969,9 +969,9 @@ gst_mythtv_src_uri_get_type (void)
 static gchar **
 gst_mythtv_src_uri_get_protocols (void)
 {
-  static gchar *protocols[] = { "myth", "myths", NULL };
+  static const gchar *protocols[] = { "myth", "myths", NULL };
 
-  return protocols;
+  return (gchar **) protocols;
 }
 
 static const gchar *
diff --git a/ext/neon/gstneonhttpsrc.c b/ext/neon/gstneonhttpsrc.c
index fd704f85b..653e21e4e 100644
--- a/ext/neon/gstneonhttpsrc.c
+++ b/ext/neon/gstneonhttpsrc.c
@@ -1026,8 +1026,8 @@ gst_neonhttp_src_uri_get_type (void)
 static gchar **
 gst_neonhttp_src_uri_get_protocols (void)
 {
-  static gchar *protocols[] = { "http", "https", NULL };
-  return protocols;
+  static const gchar *protocols[] = { "http", "https", NULL };
+  return (gchar **) protocols;
 }
 
 static const gchar *
diff --git a/ext/resindvd/resindvdbin.c b/ext/resindvd/resindvdbin.c
index df0df2d0b..e1d6c16a8 100644
--- a/ext/resindvd/resindvdbin.c
+++ b/ext/resindvd/resindvdbin.c
@@ -175,7 +175,7 @@ rsn_dvdbin_uri_get_type (void)
 static gchar **
 rsn_dvdbin_uri_get_protocols (void)
 {
-  static gchar *protocols[] = { "dvd", NULL };
+  static gchar *protocols[] = { (char *) "dvd", NULL };
 
   return protocols;
 }
diff --git a/ext/timidity/gsttimidity.c b/ext/timidity/gsttimidity.c
index d6a0ccc4a..5b083892a 100644
--- a/ext/timidity/gsttimidity.c
+++ b/ext/timidity/gsttimidity.c
@@ -128,7 +128,7 @@ gst_timidity_init (GstTimidity * filter, GstTimidityClass * g_class)
   GstElementClass *klass = GST_ELEMENT_GET_CLASS (filter);
 
   /* initialise timidity library */
-  if (mid_init (TIMIDITY_CFG) == 0) {
+  if (mid_init ((char *) TIMIDITY_CFG) == 0) {
     filter->initialized = TRUE;
   } else {
     GST_WARNING ("can't initialize timidity with config: " TIMIDITY_CFG);
diff --git a/ext/xvid/gstxvid.c b/ext/xvid/gstxvid.c
index fa5ebdc84..320516923 100644
--- a/ext/xvid/gstxvid.c
+++ b/ext/xvid/gstxvid.c
@@ -58,10 +58,10 @@ gst_xvid_init (void)
   return TRUE;
 }
 
-gchar *
+const gchar *
 gst_xvid_error (int errorcode)
 {
-  gchar *error;
+  const gchar *error;
 
   switch (errorcode) {
     case XVID_ERR_FAIL:
diff --git a/ext/xvid/gstxvid.h b/ext/xvid/gstxvid.h
index 4dca2c21b..cb28ccb72 100644
--- a/ext/xvid/gstxvid.h
+++ b/ext/xvid/gstxvid.h
@@ -42,15 +42,15 @@ G_BEGIN_DECLS
   "green_mask = (int) " G_STRINGIFY (g_mask) ", " \
   "blue_mask = (int) " G_STRINGIFY (b_mask)
 
-extern gchar *	gst_xvid_error (int errorcode);
-extern gboolean	gst_xvid_init  (void);
-
-extern gint     gst_xvid_structure_to_csp (GstStructure *structure);
-extern GstCaps *gst_xvid_csp_to_caps      (gint csp, gint w, gint h);
-extern gint     gst_xvid_image_get_size (gint csp,
+extern const gchar *gst_xvid_error (int errorcode);
+extern gboolean	    gst_xvid_init  (void);
+
+extern gint         gst_xvid_structure_to_csp (GstStructure *structure);
+extern GstCaps *    gst_xvid_csp_to_caps      (gint csp, gint w, gint h);
+extern gint         gst_xvid_image_get_size (gint csp,
+                                             gint width, gint height);
+extern gint         gst_xvid_image_fill (xvid_image_t * im, void * ptr, gint csp,
                                          gint width, gint height);
-extern gint     gst_xvid_image_fill (xvid_image_t * im, void * ptr, gint csp,
-                                     gint width, gint height);
 
 G_END_DECLS
 
diff --git a/gst/adpcmenc/adpcmenc.c b/gst/adpcmenc/adpcmenc.c
index 0a9d0e96f..bc45c3da4 100644
--- a/gst/adpcmenc/adpcmenc.c
+++ b/gst/adpcmenc/adpcmenc.c
@@ -152,8 +152,8 @@ adpcmenc_setup (ADPCMEnc * enc)
   const int DVI_IMA_HEADER_SIZE = 4;
   const int ADPCM_SAMPLES_PER_BYTE = 2;
   guint64 sample_bytes;
+  const char *layout;
 
-  char *layout;
   switch (enc->layout) {
     case LAYOUT_ADPCM_DVI:
       layout = "dvi";
diff --git a/gst/dataurisrc/gstdataurisrc.c b/gst/dataurisrc/gstdataurisrc.c
index bb4b895fe..17ebf4b10 100644
--- a/gst/dataurisrc/gstdataurisrc.c
+++ b/gst/dataurisrc/gstdataurisrc.c
@@ -314,7 +314,7 @@ gst_data_uri_src_get_uri_type (void)
 static gchar **
 gst_data_uri_src_get_protocols (void)
 {
-  static gchar *protocols[] = { "data", 0 };
+  static gchar *protocols[] = { (char *) "data", 0 };
 
   return protocols;
 }
@@ -423,8 +423,8 @@ gst_data_uri_src_set_uri (GstURIHandler * handler, const gchar * uri)
     gchar *data;
 
     data =
-        g_convert_with_fallback (old_data, -1, "UTF-8", charset, "*", &read,
-        &written, NULL);
+        g_convert_with_fallback (old_data, -1, "UTF-8", charset, (char *) "*",
+        &read, &written, NULL);
     g_free (old_data);
     GST_BUFFER_DATA (src->buffer) = GST_BUFFER_MALLOCDATA (src->buffer) =
         (guint8 *) data;
diff --git a/gst/dtmf/gstdtmfsrc.c b/gst/dtmf/gstdtmfsrc.c
index f1244b62b..8831b39cf 100644
--- a/gst/dtmf/gstdtmfsrc.c
+++ b/gst/dtmf/gstdtmfsrc.c
@@ -147,7 +147,7 @@
 
 typedef struct st_dtmf_key
 {
-  char *event_name;
+  const char *event_name;
   int event_encoding;
   float low_frequency;
   float high_frequency;
diff --git a/gst/dtmf/gstrtpdtmfdepay.c b/gst/dtmf/gstrtpdtmfdepay.c
index 9f5ae9278..00ea508e5 100644
--- a/gst/dtmf/gstrtpdtmfdepay.c
+++ b/gst/dtmf/gstrtpdtmfdepay.c
@@ -117,7 +117,7 @@
 
 typedef struct st_dtmf_key
 {
-  char *event_name;
+  const char *event_name;
   int event_encoding;
   float low_frequency;
   float high_frequency;
diff --git a/gst/festival/gstfestival.h b/gst/festival/gstfestival.h
index 66350f442..d099954e6 100644
--- a/gst/festival/gstfestival.h
+++ b/gst/festival/gstfestival.h
@@ -75,9 +75,9 @@ extern "C" {
 typedef struct FT_Info
 {
     int encoding;
-    char *server_host;
+    const char *server_host;
     int server_port;
-    char *text_mode;
+    const char *text_mode;
     
     int server_fd;
 } FT_Info;
diff --git a/gst/id3tag/id3tag.c b/gst/id3tag/id3tag.c
index 899bd4be2..301307e5d 100644
--- a/gst/id3tag/id3tag.c
+++ b/gst/id3tag/id3tag.c
@@ -926,7 +926,7 @@ add_relative_volume_tag (GstId3v2Tag * id3v2tag, const GstTagList * list,
   gint16 gain_int;
   guint8 peak_bits;
   GstId3v2Frame frame;
-  gchar *frame_id;
+  const gchar *frame_id;
 
   /* figure out tag names and the identification string to use */
   if (strcmp (tag, GST_TAG_TRACK_PEAK) == 0 ||
@@ -1154,7 +1154,8 @@ latin1_convert (const GstTagList * list, const gchar * tag,
 
   /* Convert to Latin-1 (ISO-8859-1), replacing unrepresentable characters
      with '?' */
-  latin1 = g_convert_with_fallback (str, -1, "ISO-8859-1", "UTF-8", "?",
+  latin1 =
+      g_convert_with_fallback (str, -1, "ISO-8859-1", "UTF-8", (char *) "?",
       NULL, &len, NULL);
 
   if (latin1 != NULL && *latin1 != '\0') {
diff --git a/gst/mpegdemux/mpegtspacketizer.c b/gst/mpegdemux/mpegtspacketizer.c
index ccc3262d7..875f9712e 100644
--- a/gst/mpegdemux/mpegtspacketizer.c
+++ b/gst/mpegdemux/mpegtspacketizer.c
@@ -799,10 +799,10 @@ mpegts_packetizer_parse_nit (MpegTSPacketizer * packetizer,
             DESC_DVB_SATELLITE_DELIVERY_SYSTEM_west_east_flag (delivery);
         guint8 polarization =
             DESC_DVB_SATELLITE_DELIVERY_SYSTEM_polarization (delivery);
-        gchar *polarization_str;
+        const gchar *polarization_str;
         guint8 modulation =
             DESC_DVB_SATELLITE_DELIVERY_SYSTEM_modulation (delivery);
-        gchar *modulation_str;
+        const gchar *modulation_str;
         guint8 *symbol_rate_bcd =
             DESC_DVB_SATELLITE_DELIVERY_SYSTEM_symbol_rate (delivery);
         guint32 symbol_rate =
@@ -814,7 +814,7 @@ mpegts_packetizer_parse_nit (MpegTSPacketizer * packetizer,
             100000 * ((symbol_rate_bcd[0] & 0xF0) >> 4);
         guint8 fec_inner =
             DESC_DVB_SATELLITE_DELIVERY_SYSTEM_fec_inner (delivery);
-        gchar *fec_inner_str;
+        const gchar *fec_inner_str;
 
         switch (polarization) {
           case 0:
@@ -914,7 +914,7 @@ mpegts_packetizer_parse_nit (MpegTSPacketizer * packetizer,
             DESC_DVB_TERRESTRIAL_DELIVERY_SYSTEM_transmission_mode (delivery);
         gboolean other_frequency =
             DESC_DVB_TERRESTRIAL_DELIVERY_SYSTEM_other_frequency (delivery);
-        gchar *constellation_str, *code_rate_hp_str, *code_rate_lp_str,
+        const gchar *constellation_str, *code_rate_hp_str, *code_rate_lp_str,
             *transmission_mode_str;
         /* do the stuff */
         /* bandwidth is 8 if 0, 7 if 1, 6 if 2, reserved otherwise */
@@ -1041,7 +1041,7 @@ mpegts_packetizer_parse_nit (MpegTSPacketizer * packetizer,
             10000000 * ((frequency_bcd[0] & 0xF0) >> 4));
         guint8 modulation =
             DESC_DVB_CABLE_DELIVERY_SYSTEM_modulation (delivery);
-        gchar *modulation_str;
+        const gchar *modulation_str;
         guint8 *symbol_rate_bcd =
             DESC_DVB_CABLE_DELIVERY_SYSTEM_symbol_rate (delivery);
         guint32 symbol_rate =
@@ -1052,7 +1052,7 @@ mpegts_packetizer_parse_nit (MpegTSPacketizer * packetizer,
             10000 * (symbol_rate_bcd[0] & 0x0F) +
             100000 * ((symbol_rate_bcd[0] & 0xF0) >> 4);
         guint8 fec_inner = DESC_DVB_CABLE_DELIVERY_SYSTEM_fec_inner (delivery);
-        gchar *fec_inner_str;
+        const gchar *fec_inner_str;
 
         switch (fec_inner) {
           case 0:
@@ -1386,7 +1386,7 @@ mpegts_packetizer_parse_sdt (MpegTSPacketizer * packetizer,
             (gchar *) DESC_DVB_SERVICE_name_text (service_descriptor);
         if (servicename_length + serviceprovider_name_length + 2 <=
             DESC_LENGTH (service_descriptor)) {
-          gchar *running_status_tmp;
+          const gchar *running_status_tmp;
           switch (running_status) {
             case 0:
               running_status_tmp = "undefined";
@@ -1700,7 +1700,7 @@ mpegts_packetizer_parse_eit (MpegTSPacketizer * packetizer,
           gint freq = 25;       /* 25 or 30 measured in Hertz */
           gboolean highdef = FALSE;
           gboolean panvectors = FALSE;
-          gchar *comptype = "";
+          const gchar *comptype = "";
 
           comp_descriptor = g_array_index (component_descriptors, guint8 *, i);
           switch (DESC_DVB_COMPONENT_stream_content (comp_descriptor)) {
diff --git a/gst/mxf/mxftypes.c b/gst/mxf/mxftypes.c
index e678da63c..6fcfdeb1e 100644
--- a/gst/mxf/mxftypes.c
+++ b/gst/mxf/mxftypes.c
@@ -645,8 +645,8 @@ mxf_utf8_to_utf16 (const gchar * str, guint16 * size)
   }
 
   ret = (guint8 *)
-      g_convert_with_fallback (str, -1, "UTF-16BE", "UTF-8", "*", NULL, &s,
-      &error);
+      g_convert_with_fallback (str, -1, "UTF-16BE", "UTF-8", (char *) "*", NULL,
+      &s, &error);
 
   if (ret == NULL) {
     GST_WARNING ("UTF-16-BE to UTF-8 conversion failed: %s", error->message);
diff --git a/gst/qtmux/atoms.c b/gst/qtmux/atoms.c
index 841900d55..d87174e72 100644
--- a/gst/qtmux/atoms.c
+++ b/gst/qtmux/atoms.c
@@ -2817,7 +2817,7 @@ atom_hdlr_set_type (AtomHDLR * hdlr, AtomsContext * context, guint32 comp_type,
 }
 
 static void
-atom_hdlr_set_name (AtomHDLR * hdlr, char *name)
+atom_hdlr_set_name (AtomHDLR * hdlr, const char *name)
 {
   if (hdlr->name)
     g_free (hdlr->name);
diff --git a/gst/qtmux/gstqtmuxmap.h b/gst/qtmux/gstqtmuxmap.h
index 67c613902..8e89351dd 100644
--- a/gst/qtmux/gstqtmuxmap.h
+++ b/gst/qtmux/gstqtmuxmap.h
@@ -61,9 +61,9 @@ typedef enum _GstQTMuxFormat
 typedef struct _GstQTMuxFormatProp
 {
   GstQTMuxFormat format;
-  gchar *name;
-  gchar *long_name;
-  gchar *type_name;
+  const gchar *name;
+  const gchar *long_name;
+  const gchar *type_name;
   GstStaticCaps src_caps;
   GstStaticCaps video_sink_caps;
   GstStaticCaps audio_sink_caps;
diff --git a/gst/real/gstrealaudiodec.c b/gst/real/gstrealaudiodec.c
index b3f2ad52e..70103cee0 100644
--- a/gst/real/gstrealaudiodec.c
+++ b/gst/real/gstrealaudiodec.c
@@ -87,7 +87,7 @@ typedef struct
     guint16 (*RAOpenCodec2) (gpointer, const gchar *);
     guint16 (*RASetFlavor) (gpointer, guint16);
   void (*SetDLLAccessPath) (gchar *);
-  void (*RASetPwd) (gpointer, gchar *);
+  void (*RASetPwd) (gpointer, const gchar *);
 } GstRADecLibrary;
 
 typedef struct
@@ -211,7 +211,7 @@ close_library (GstRealAudioDec * dec, GstRADecLibrary * lib)
 static gboolean
 open_library (GstRealAudioDec * dec, gint version, GstRADecLibrary * lib)
 {
-  gchar *path, *names;
+  const gchar *path, *names;
   gchar **split_names, **split_path;
   gint i, j;
   gpointer ra_close_codec, ra_decode, ra_free_decoder;
@@ -300,7 +300,7 @@ codec_search_done:
   lib->RAOpenCodec2 = (guint16 (*)(gpointer, const gchar *)) ra_open_codec2;
   lib->RAInitDecoder = (guint16 (*)(gpointer, gpointer)) ra_init_decoder;
   lib->RASetFlavor = (guint16 (*)(gpointer, guint16)) ra_set_flavor;
-  lib->RASetPwd = (void (*)(gpointer, gchar *)) ra_set_pwd;
+  lib->RASetPwd = (void (*)(gpointer, const gchar *)) ra_set_pwd;
   lib->SetDLLAccessPath = (void (*)(gchar *)) set_dll_access_path;
 
   if (lib->SetDLLAccessPath)
diff --git a/gst/real/gstrealvideodec.c b/gst/real/gstrealvideodec.c
index 4485a312f..0c4fb1542 100644
--- a/gst/real/gstrealvideodec.c
+++ b/gst/real/gstrealvideodec.c
@@ -443,7 +443,7 @@ open_library (GstRealVideoDec * dec, GstRealVideoDecVersion version,
 {
   gpointer rv_custom_msg, rv_free, rv_init, rv_transform;
   GModule *module = NULL;
-  gchar *path, *names;
+  const gchar *path, *names;
   gchar **split_names, **split_path;
   int i, j;
 
diff --git a/gst/sdp/gstsdpdemux.c b/gst/sdp/gstsdpdemux.c
index 3f9306e27..47c6e4a60 100644
--- a/gst/sdp/gstsdpdemux.c
+++ b/gst/sdp/gstsdpdemux.c
@@ -682,8 +682,8 @@ gst_sdp_demux_media_to_caps (gint pt, const GstSDPMedia * media)
       /* <param>[=<value>] are separated with ';' */
       pairs = g_strsplit (p, ";", 0);
       for (i = 0; pairs[i]; i++) {
-        gchar *valpos;
-        gchar *val, *key;
+        gchar *valpos, *key;
+        const gchar *val;
 
         /* the key may not have a '=', the value can have other '='s */
         valpos = strstr (pairs[i], "=");
@@ -933,7 +933,8 @@ start_session_failure:
 static gboolean
 gst_sdp_demux_stream_configure_udp (GstSDPDemux * demux, GstSDPStream * stream)
 {
-  gchar *uri, *name, *destination;
+  gchar *uri, *name;
+  const gchar *destination;
   GstPad *pad;
 
   GST_DEBUG_OBJECT (demux, "creating UDP sources for multicast");
diff --git a/sys/dvb/dvbbasebin.c b/sys/dvb/dvbbasebin.c
index 5118146eb..207b7e112 100644
--- a/sys/dvb/dvbbasebin.c
+++ b/sys/dvb/dvbbasebin.c
@@ -973,7 +973,7 @@ dvb_base_bin_uri_get_type (void)
 static gchar **
 dvb_base_bin_uri_get_protocols (void)
 {
-  static gchar *protocols[] = { "dvb", NULL };
+  static gchar *protocols[] = { (char *) "dvb", NULL };
 
   return protocols;
 }
diff --git a/sys/dvb/gstdvbsrc.c b/sys/dvb/gstdvbsrc.c
index a9cda667e..cb2e12740 100644
--- a/sys/dvb/gstdvbsrc.c
+++ b/sys/dvb/gstdvbsrc.c
@@ -687,7 +687,7 @@ static gboolean
 gst_dvbsrc_open_frontend (GstDvbSrc * object)
 {
   struct dvb_frontend_info fe_info;
-  char *adapter_desc = NULL;
+  const char *adapter_desc = NULL;
   gchar *frontend_dev;
   GstStructure *adapter_structure;
   char *adapter_name = NULL;
diff --git a/sys/dvb/parsechannels.c b/sys/dvb/parsechannels.c
index 3df3a6df5..6de7b12a3 100644
--- a/sys/dvb/parsechannels.c
+++ b/sys/dvb/parsechannels.c
@@ -37,14 +37,14 @@ parse_channels_conf_from_file (const gchar * filename)
   gchar **lines;
   gchar *line;
   gchar **fields;
-  gchar *terrestrial[] = { "inversion", "bandwidth",
+  const gchar *terrestrial[] = { "inversion", "bandwidth",
     "code-rate-hp", "code-rate-lp", "modulation", "transmission-mode",
     "guard", "hierarchy"
   };
-  gchar *satellite[] = { "polarity", "diseqc-source",
+  const gchar *satellite[] = { "polarity", "diseqc-source",
     "symbol-rate"
   };
-  gchar *cable[] = { "inversion", "symbol-rate", "code-rate-hp",
+  const gchar *cable[] = { "inversion", "symbol-rate", "code-rate-hp",
     "modulation"
   };
   int i;
diff --git a/sys/vcd/vcdsrc.c b/sys/vcd/vcdsrc.c
index 938b1b19e..fa6f0439c 100644
--- a/sys/vcd/vcdsrc.c
+++ b/sys/vcd/vcdsrc.c
@@ -458,7 +458,7 @@ gst_vcdsrc_uri_get_type (void)
 static gchar **
 gst_vcdsrc_uri_get_protocols (void)
 {
-  static gchar *protocols[] = { "vcd", NULL };
+  static gchar *protocols[] = { (char *) "vcd", NULL };
 
   return protocols;
 }
diff --git a/tests/check/elements/asfmux.c b/tests/check/elements/asfmux.c
index 40834e9ff..6c3dab511 100644
--- a/tests/check/elements/asfmux.c
+++ b/tests/check/elements/asfmux.c
@@ -57,7 +57,7 @@ static GstStaticPadTemplate srcaudiotemplate = GST_STATIC_PAD_TEMPLATE ("src",
 
 static GstPad *
 setup_src_pad (GstElement * element,
-    GstStaticPadTemplate * template, GstCaps * caps, gchar * sinkname)
+    GstStaticPadTemplate * template, GstCaps * caps, const gchar * sinkname)
 {
   GstPad *srcpad, *sinkpad;
 
@@ -86,7 +86,7 @@ setup_src_pad (GstElement * element,
 }
 
 static void
-teardown_src_pad (GstElement * element, gchar * sinkname)
+teardown_src_pad (GstElement * element, const gchar * sinkname)
 {
   GstPad *srcpad, *sinkpad;
   gchar *padname;
@@ -122,7 +122,7 @@ teardown_src_pad (GstElement * element, gchar * sinkname)
 }
 
 static GstElement *
-setup_asfmux (GstStaticPadTemplate * srctemplate, gchar * sinkname)
+setup_asfmux (GstStaticPadTemplate * srctemplate, const gchar * sinkname)
 {
   GstElement *asfmux;
 
@@ -137,7 +137,7 @@ setup_asfmux (GstStaticPadTemplate * srctemplate, gchar * sinkname)
 }
 
 static void
-cleanup_asfmux (GstElement * asfmux, gchar * sinkname)
+cleanup_asfmux (GstElement * asfmux, const gchar * sinkname)
 {
   GST_DEBUG ("cleanup_asfmux");
   gst_element_set_state (asfmux, GST_STATE_NULL);
@@ -149,8 +149,8 @@ cleanup_asfmux (GstElement * asfmux, gchar * sinkname)
 }
 
 static void
-check_asfmux_pad (GstStaticPadTemplate * srctemplate, gchar * src_caps_string,
-    gchar * sinkname)
+check_asfmux_pad (GstStaticPadTemplate * srctemplate,
+    const gchar * src_caps_string, const gchar * sinkname)
 {
   GstElement *asfmux;
   GstBuffer *inbuffer;
diff --git a/tests/check/elements/autoconvert.c b/tests/check/elements/autoconvert.c
index 83813bd9f..c36247f70 100644
--- a/tests/check/elements/autoconvert.c
+++ b/tests/check/elements/autoconvert.c
@@ -62,7 +62,7 @@ teardown (void)
 static void
 set_autoconvert_factories (GstElement * autoconvert)
 {
-  gchar *desired_features[] = { "testelement1", "testelement2" };
+  const gchar *desired_features[] = { "testelement1", "testelement2" };
   GstElementFactory *feature;
   GList *factories = NULL;
   gint i;
@@ -167,7 +167,7 @@ autoconvert_suite (void)
 /* Implementation of the test elements */
 
 static void
-configure_test_element (GstBin * bin, gchar * capsfilter)
+configure_test_element (GstBin * bin, const gchar * capsfilter)
 {
   GstElement *filter;
   GstElement *identity;
diff --git a/tests/check/elements/mplex.c b/tests/check/elements/mplex.c
index 0b62e247e..356de173f 100644
--- a/tests/check/elements/mplex.c
+++ b/tests/check/elements/mplex.c
@@ -118,7 +118,7 @@ test_sink_event (GstPad * pad, GstEvent * event)
 /* setup and teardown needs some special handling for muxer */
 static GstPad *
 setup_src_pad (GstElement * element,
-    GstStaticPadTemplate * template, GstCaps * caps, gchar * sinkname)
+    GstStaticPadTemplate * template, GstCaps * caps, const gchar * sinkname)
 {
   GstPad *srcpad, *sinkpad;
 
@@ -146,7 +146,7 @@ setup_src_pad (GstElement * element,
 }
 
 static void
-teardown_src_pad (GstElement * element, gchar * sinkname)
+teardown_src_pad (GstElement * element, const gchar * sinkname)
 {
   GstPad *srcpad, *sinkpad;
   gchar *padname;
diff --git a/tests/check/elements/qtmux.c b/tests/check/elements/qtmux.c
index 0c0581812..c5d6d1c35 100644
--- a/tests/check/elements/qtmux.c
+++ b/tests/check/elements/qtmux.c
@@ -58,7 +58,7 @@ static GstStaticPadTemplate srcaudiotemplate = GST_STATIC_PAD_TEMPLATE ("src",
 /* setup and teardown needs some special handling for muxer */
 static GstPad *
 setup_src_pad (GstElement * element,
-    GstStaticPadTemplate * template, GstCaps * caps, gchar * sinkname)
+    GstStaticPadTemplate * template, GstCaps * caps, const gchar * sinkname)
 {
   GstPad *srcpad, *sinkpad;
 
@@ -111,7 +111,7 @@ teardown_src_pad (GstPad * srcpad)
 }
 
 static GstElement *
-setup_qtmux (GstStaticPadTemplate * srctemplate, gchar * sinkname)
+setup_qtmux (GstStaticPadTemplate * srctemplate, const gchar * sinkname)
 {
   GstElement *qtmux;
 
@@ -126,7 +126,7 @@ setup_qtmux (GstStaticPadTemplate * srctemplate, gchar * sinkname)
 }
 
 static void
-cleanup_qtmux (GstElement * qtmux, gchar * sinkname)
+cleanup_qtmux (GstElement * qtmux, const gchar * sinkname)
 {
   GST_DEBUG ("cleanup_qtmux");
   gst_element_set_state (qtmux, GST_STATE_NULL);
@@ -139,7 +139,7 @@ cleanup_qtmux (GstElement * qtmux, gchar * sinkname)
 }
 
 static void
-check_qtmux_pad (GstStaticPadTemplate * srctemplate, gchar * sinkname)
+check_qtmux_pad (GstStaticPadTemplate * srctemplate, const gchar * sinkname)
 {
   GstElement *qtmux;
   GstBuffer *inbuffer, *outbuffer;
diff --git a/tests/check/elements/selector.c b/tests/check/elements/selector.c
index e9449c030..56d2840ec 100644
--- a/tests/check/elements/selector.c
+++ b/tests/check/elements/selector.c
@@ -38,7 +38,7 @@ static gboolean
 probe_cb (GstPad * pad, GstMiniObject * obj, gpointer user_data)
 {
   gint count = 0;
-  gchar *count_type = NULL;
+  const gchar *count_type = NULL;
 
   GST_LOG_OBJECT (pad, "got data");
 
@@ -184,17 +184,15 @@ count_output_buffers (GList * output_pads, gint expected_buffers)
 static void
 selector_set_active_pad (GstElement * elem, GstPad * selpad)
 {
-  gchar *padname = "";
+  gchar *padname = NULL;
 
   if (selpad) {
     padname = gst_pad_get_name (selpad);
   }
 
   g_object_set (G_OBJECT (elem), "active-pad", selpad, NULL);
-  GST_DEBUG_OBJECT (elem, "activated selector pad: %s", padname);
-  if (selpad) {
-    g_free (padname);
-  }
+  GST_DEBUG_OBJECT (elem, "activated selector pad: %s", GST_STR_NULL (padname));
+  g_free (padname);
 }
 
 /* Push buffers and switch for each selector pad */
diff --git a/tests/examples/camerabin/gst-camera.c b/tests/examples/camerabin/gst-camera.c
index 52c72c6b3..3082a0ff5 100644
--- a/tests/examples/camerabin/gst-camera.c
+++ b/tests/examples/camerabin/gst-camera.c
@@ -127,8 +127,8 @@ static guint32 num_vids = 0;
 
 static gint max_fr_n = 0;
 static gint max_fr_d = 0;
-static gchar *video_post;
-static gchar *image_post;
+static const gchar *video_post;
+static const gchar *image_post;
 
 static GList *video_caps_list = NULL;
 
@@ -139,7 +139,7 @@ static gchar *iso_speed_labels[] = { "auto", "100", "200", "400" };
 
 static struct
 {
-  gchar *label;
+  const gchar *label;
   gint width;
   gint height;
 } image_resolution_label_map[] = {
@@ -920,8 +920,8 @@ on_radiobuttonVideoCapture_toggled (GtkToggleButton * togglebutton,
   }
 }
 
-void
-on_rbBntVidEff_toggled (GtkToggleButton * togglebutton, gchar * effect)
+static void
+on_rbBntVidEff_toggled (GtkToggleButton * togglebutton, const gchar * effect)
 {
   if (gtk_toggle_button_get_active (togglebutton)) {
     /* lets also use those effects to image */
@@ -1601,7 +1601,7 @@ static gboolean
 ui_create (void)
 {
   GError *error = NULL;
-  gchar *uifile = DEFAULT_UI_FILE;
+  const gchar *uifile = DEFAULT_UI_FILE;
 
   if (!g_file_test (uifile, G_FILE_TEST_EXISTS)) {
     uifile = SHARED_UI_FILE;
diff --git a/tests/examples/camerabin/gst-camera.h b/tests/examples/camerabin/gst-camera.h
index b027ecd23..f1d88446c 100644
--- a/tests/examples/camerabin/gst-camera.h
+++ b/tests/examples/camerabin/gst-camera.h
@@ -55,9 +55,6 @@ on_radiobuttonVideoCapture_toggled (GtkToggleButton * togglebutton,
     gpointer user_data);
 
 void
-on_rbBntVidEff_toggled (GtkToggleButton * togglebutton, gchar * effect);
-
-void
 on_rbBntVidEffNone_toggled (GtkToggleButton * togglebutton, gpointer data);
 
 void
diff --git a/tests/examples/scaletempo/demo-gui.c b/tests/examples/scaletempo/demo-gui.c
index 5ff976064..9d5779052 100644
--- a/tests/examples/scaletempo/demo-gui.c
+++ b/tests/examples/scaletempo/demo-gui.c
@@ -411,7 +411,7 @@ demo_gui_do_playlist_next (GtkAction * action, gpointer data)
 static void
 demo_gui_do_about_dialog (GtkAction * action, gpointer data)
 {
-  static gchar *authors[] =
+  static const gchar *authors[] =
       { "Rov Juvano <rovjuvano@users.sourceforge.net>", NULL };
 
   gtk_show_about_dialog (NULL,
diff --git a/tests/examples/scaletempo/demo-main.c b/tests/examples/scaletempo/demo-main.c
index 0902d7b26..6ddcde71d 100644
--- a/tests/examples/scaletempo/demo-main.c
+++ b/tests/examples/scaletempo/demo-main.c
@@ -26,10 +26,15 @@ extern GOptionGroup *gtk_get_option_group (gboolean);
 extern GOptionGroup *gst_init_get_option_group (void);
 
 static void
-handle_error_message (DemoPlayer * player, const gchar * msg, gpointer data)
+handle_player_error (DemoPlayer * player, const gchar * msg, gpointer unused)
 {
-  const gchar *format = (const gchar *) data;
-  g_print (format, msg);
+  g_print ("PLAYER ERROR: %s\n", msg);
+}
+
+static void
+handle_gui_error (DemoPlayer * player, const gchar * msg, gpointer unused)
+{
+  g_print ("GUI ERROR: %s\n", msg);
 }
 
 static void
@@ -71,10 +76,8 @@ main (int argc, char *argv[])
 
   gui = g_object_new (DEMO_TYPE_GUI, NULL);
   player = g_object_new (DEMO_TYPE_PLAYER, NULL);
-  g_signal_connect (player, "error", G_CALLBACK (handle_error_message),
-      "PLAYER ERROR: %s\n");
-  g_signal_connect (gui, "error", G_CALLBACK (handle_error_message),
-      "GUI ERROR: %s\n");
+  g_signal_connect (player, "error", G_CALLBACK (handle_player_error), NULL);
+  g_signal_connect (gui, "error", G_CALLBACK (handle_gui_error), NULL);
   demo_gui_set_player (gui, player);
 
   loop = g_main_loop_new (NULL, FALSE);