/usr/share/doc/gstreamer0.10-doc/pwg/html/section-checklist-debug.html

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>23.2. Debugging</A
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>&#13;          Elements should <SPAN
CLASS="emphasis"
><I
CLASS="emphasis"
>never</I
></SPAN
> use their standard
          output for debugging (using functions such as <CODE
CLASS="function"
>printf
          ()</CODE
> or <CODE
CLASS="function"
>g_print ()</CODE
>). Instead,
          elements should use the logging functions provided by <SPAN
CLASS="application"
>GStreamer</SPAN
>,
          named <CODE
CLASS="function"
>GST_DEBUG ()</CODE
>,
          <CODE
CLASS="function"
>GST_LOG ()</CODE
>, <CODE
CLASS="function"
>GST_INFO ()</CODE
>,
          <CODE
CLASS="function"
>GST_WARNING ()</CODE
> and
          <CODE
CLASS="function"
>GST_ERROR ()</CODE
>. The various logging levels can
          be turned on and off at runtime and can thus be used for solving
          issues as they turn up. Instead of <CODE
CLASS="function"
>GST_LOG ()</CODE
>
          (as an example), you can also use <CODE
CLASS="function"
>GST_LOG_OBJECT
          ()</CODE
> to print the object that you're logging output for.
        </P
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><P
>&#13;          Ideally, elements should use their own debugging category. Most
          elements use the following code to do that:
        </P
><PRE
CLASS="programlisting"
>&#13;GST_DEBUG_CATEGORY_STATIC (myelement_debug);
#define GST_CAT_DEFAULT myelement_debug

[..]

static void
gst_myelement_class_init (GstMyelementClass *klass)
{
[..]
  GST_DEBUG_CATEGORY_INIT (myelement_debug, "myelement",
			   0, "My own element");
}
        </PRE
><P
>&#13;          At runtime, you can turn on debugging using the commandline
          option <B
CLASS="command"
>--gst-debug=myelement:5</B
>.
        </P
></LI
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><P
>&#13;          Elements should use GST_DEBUG_FUNCPTR when setting pad functions or
          overriding element class methods, for example:
          <PRE
CLASS="programlisting"
>&#13;gst_pad_set_event_func (myelement-&#62;srcpad,
    GST_DEBUG_FUNCPTR (my_element_src_event));
          </PRE
>
          This makes debug output much easier to read later on.
        </P
></LI
><LI
><P
>&#13;          Elements that are aimed for inclusion into one of the GStreamer
          modules should ensure consistent naming of the element name,
          structures and function names. For example, if the element type is
          GstYellowFooDec, functions should be prefixed with
          gst_yellow_foo_dec_ and the element should be registered
          as 'yellowfoodec'. Separate words should be separate in this scheme,
          so it should be GstFooDec and gst_foo_dec, and not GstFoodec and
          gst_foodec.
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gstreamer0.10-doc 0.10.36-1.5ubuntu1 / usr / share / doc / gstreamer0.10-doc / pwg / html / section-checklist-debug.html
