GstInfo

## GstInfo GstInfo — Debugging and logging facilities |

## Synopsis

    #include <gst/gst.h>

    enum                GstDebugLevel;
    #define             GST_LEVEL_DEFAULT
    enum                GstDebugColorFlags;
    struct              GstDebugCategory;
    enum                GstDebugGraphDetails;
    #define             GST_STR_NULL                        (str)
    #define             GST_DEBUG_PAD_NAME                  (pad)
    #define             GST_FUNCTION
    void                (*GstLogFunction)                   (GstDebugCategory *category,
                                                             GstDebugLevel level,
                                                             const gchar *file,
                                                             const gchar *function,
                                                             gint line,
                                                             GObject *object,
                                                             GstDebugMessage *message,
                                                             gpointer data);
    void                gst_debug_log                       (GstDebugCategory *category,
                                                             GstDebugLevel level,
                                                             const gchar *file,
                                                             const gchar *function,
                                                             gint line,
                                                             GObject *object,
                                                             const gchar *format,
                                                             ...);
    void                gst_debug_log_valist                (GstDebugCategory *category,
                                                             GstDebugLevel level,
                                                             const gchar *file,
                                                             const gchar *function,
                                                             gint line,
                                                             GObject *object,
                                                             const gchar *format,
                                                             va_list args);
    const gchar *       gst_debug_message_get               (GstDebugMessage *message);
    void                gst_debug_log_default               (GstDebugCategory *category,
                                                             GstDebugLevel level,
                                                             const gchar *file,
                                                             const gchar *function,
                                                             gint line,
                                                             GObject *object,
                                                             GstDebugMessage *message,
                                                             gpointer unused);
    const gchar *       gst_debug_level_get_name            (GstDebugLevel level);
    void                gst_debug_add_log_function          (GstLogFunction func,
                                                             gpointer data);
    guint               gst_debug_remove_log_function       (GstLogFunction func);
    guint               gst_debug_remove_log_function_by_data
                                                            (gpointer data);
    void                gst_debug_set_active                (gboolean active);
    gboolean            gst_debug_is_active                 (void);
    void                gst_debug_set_colored               (gboolean colored);
    gboolean            gst_debug_is_colored                (void);
    void                gst_debug_set_default_threshold     (GstDebugLevel level);
    GstDebugLevel       gst_debug_get_default_threshold     (void);
    void                gst_debug_set_threshold_for_name    (const gchar *name,
                                                             GstDebugLevel level);
    void                gst_debug_unset_threshold_for_name  (const gchar *name);
    #define             GST_DEBUG_CATEGORY                  (cat)
    #define             GST_DEBUG_CATEGORY_EXTERN           (cat)
    #define             GST_DEBUG_CATEGORY_STATIC           (cat)
    #define             GST_DEBUG_CATEGORY_INIT             (cat,
                                                             name,
                                                             color,
                                                             description)
    #define             GST_DEBUG_CATEGORY_GET              (cat,
                                                             name)
    void                gst_debug_category_free             (GstDebugCategory *category);
    void                gst_debug_category_set_threshold    (GstDebugCategory *category,
                                                             GstDebugLevel level);
    void                gst_debug_category_reset_threshold  (GstDebugCategory *category);
    GstDebugLevel       gst_debug_category_get_threshold    (GstDebugCategory *category);
    const gchar *       gst_debug_category_get_name         (GstDebugCategory *category);
    guint               gst_debug_category_get_color        (GstDebugCategory *category);
    const gchar *       gst_debug_category_get_description  (GstDebugCategory *category);
    GSList *            gst_debug_get_all_categories        (void);
    gchar *             gst_debug_construct_term_color      (guint colorinfo);
    gint                gst_debug_construct_win_color       (guint colorinfo);
    #define             GST_CAT_LEVEL_LOG                   (cat,
                                                             level,
                                                             object,
                                                             ...)
    #define             GST_CAT_ERROR_OBJECT                (cat,
                                                             obj,
                                                             ...)
    #define             GST_CAT_WARNING_OBJECT              (cat,
                                                             obj,
                                                             ...)
    #define             GST_CAT_INFO_OBJECT                 (cat,
                                                             obj,
                                                             ...)
    #define             GST_CAT_DEBUG_OBJECT                (cat,
                                                             obj,
                                                             ...)
    #define             GST_CAT_LOG_OBJECT                  (cat,
                                                             obj,
                                                             ...)
    #define             GST_CAT_FIXME_OBJECT                (cat,
                                                             obj,
                                                             ...)
    #define             GST_CAT_TRACE_OBJECT                (cat,
                                                             obj,
                                                             ...)
    #define             GST_CAT_MEMDUMP_OBJECT              (cat,
                                                             obj,
                                                             msg,
                                                             data,
                                                             length)
    #define             GST_CAT_ERROR                       (cat,
                                                             ...)
    #define             GST_CAT_WARNING                     (cat,
                                                             ...)
    #define             GST_CAT_INFO                        (cat,
                                                             ...)
    #define             GST_CAT_DEBUG                       (cat,
                                                             ...)
    #define             GST_CAT_LOG                         (cat,
                                                             ...)
    #define             GST_CAT_FIXME                       (cat,
                                                             ...)
    #define             GST_CAT_TRACE                       (cat,
                                                             ...)
    #define             GST_CAT_MEMDUMP                     (cat,
                                                             msg,
                                                             data,
                                                             length)
    #define             GST_ERROR_OBJECT                    (obj,
                                                             ...)
    #define             GST_WARNING_OBJECT                  (obj,
                                                             ...)
    #define             GST_INFO_OBJECT                     (obj,
                                                             ...)
    #define             GST_DEBUG_OBJECT                    (obj,
                                                             ...)
    #define             GST_LOG_OBJECT                      (obj,
                                                             ...)
    #define             GST_FIXME_OBJECT                    (obj,
                                                             ...)
    #define             GST_TRACE_OBJECT                    (obj,
                                                             ...)
    #define             GST_MEMDUMP_OBJECT                  (obj,
                                                             msg,
                                                             data,
                                                             length)
    #define             GST_ERROR                           (...)
    #define             GST_WARNING                         (...)
    #define             GST_INFO                            (...)
    #define             GST_DEBUG                           (...)
    #define             GST_LOG                             (...)
    #define             GST_FIXME                           (...)
    #define             GST_TRACE                           (...)
    #define             GST_MEMDUMP                         (msg,
                                                             data,
                                                             length)
    #define             GST_DEBUG_REGISTER_FUNCPTR          (ptr)
    #define             GST_DEBUG_FUNCPTR                   (ptr)
    #define             GST_DEBUG_FUNCPTR_NAME              (ptr)
    #define             GST_DEBUG_BIN_TO_DOT_FILE           (bin,
                                                             details,
                                                             file_name)
    #define             GST_DEBUG_BIN_TO_DOT_FILE_WITH_TS   (bin,
                                                             details,
                                                             file_name)
    void                gst_debug_print_stack_trace         (void);
    #define             GST_TIME_FORMAT
    #define             GST_TIME_ARGS                       (t)
    void                gst_debug_bin_to_dot_file           (GstBin *bin,
                                                             GstDebugGraphDetails details,
                                                             const gchar *file_name);
    void                gst_debug_bin_to_dot_file_with_ts   (GstBin *bin,
                                                             GstDebugGraphDetails details,
                                                             const gchar *file_name);

## Description

GStreamer's debugging subsystem is an easy way to get information about what the application is doing. It is not meant for programming errors. Use GLib methods (g_warning and friends) for that.

The debugging subsystem works only after GStreamer has been initialized

- for example by calling `gst_init()`.

The debugging subsystem is used to log informational messages while the application runs. Each messages has some properties attached to it. Among these properties are the debugging category, the severity (called "level" here) and an optional GObject it belongs to. Each of these messages is sent to all registered debugging handlers, which then handle the messages. GStreamer attaches a default handler on startup, which outputs requested messages to stderr.

Messages are output by using shortcut macros like GST_DEBUG, GST_CAT_ERROR_OBJECT or similar. These all expand to calling `gst_debug_log()` with the right parameters. The only thing a developer will probably want to do is define his own categories. This is easily done with 3 lines. At the top of your code, declare the variables and set the default category.

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    GST_DEBUG_CATEGORY_STATIC (my_category);     // define category (statically)
    #define GST_CAT_DEFAULT my_category     // set as default

After that you only need to initialize the category.

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    GST_DEBUG_CATEGORY_INIT (my_category, "my category",
                             0, "This is my very own");

Initialization must be done before the category is used first. Plugins do this in their plugin_init function, libraries and applications should do that during their initialization.

The whole debugging subsystem can be disabled at build time with passing the --disable-gst-debug switch to configure. If this is done, every function, macro and even structs described in this file evaluate to default values or nothing at all. So don't take addresses of these functions or use other tricks. If you must do that for some reason, there is still an option. If the debugging subsystem was compiled out, GST_DISABLE_GST_DEBUG is defined in <gst/gst.h>, so you can check that before doing your trick. Disabling the debugging subsystem will give you a slight (read: unnoticeable) speed increase and will reduce the size of your compiled code. The GStreamer library itself becomes around 10% smaller.

Please note that there are naming conventions for the names of debugging categories. These are explained at `GST_DEBUG_CATEGORY_INIT()`.

## Details

### enum GstDebugLevel

    typedef enum {
      GST_LEVEL_NONE = 0,
      GST_LEVEL_ERROR = 1,
      GST_LEVEL_WARNING = 2,
      GST_LEVEL_FIXME = 3,
      GST_LEVEL_INFO = 4,
      GST_LEVEL_DEBUG = 5,
      GST_LEVEL_LOG = 6,
      GST_LEVEL_TRACE = 7,
      /* add more */
      GST_LEVEL_MEMDUMP = 9,
      /* add more */
      GST_LEVEL_COUNT
    } GstDebugLevel;

The level defines the importance of a debugging message. The more important a message is, the greater the probability that the debugging system outputs it.

`GST_LEVEL_NONE` | No debugging level specified or desired. Used to deactivate debugging output.
`GST_LEVEL_ERROR` | Error messages are to be used only when an error occured that stops the application from keeping working correctly. An examples is gst_element_error, which outputs a message with this priority. It does not mean that the application is terminating as with g_errror.
`GST_LEVEL_WARNING` | Warning messages are to inform about abnormal behaviour that could lead to problems or weird behaviour later on. An example of this would be clocking issues ("your computer is pretty slow") or broken input data ("Can't synchronize to stream.")
`GST_LEVEL_FIXME` | Fixme messages are messages that indicate that something in the executed code path is not fully implemented or handled yet. Note that this does not replace proper error handling in any way, the purpose of this message is to make it easier to spot incomplete/unfinished pieces of code when reading the debug log. (Since: 0.10.23)
`GST_LEVEL_INFO` | Informational messages should be used to keep the developer updated about what is happening. Examples where this should be used are when a typefind function has successfully determined the type of the stream or when an mp3 plugin detects the format to be used. ("This file has mono sound.")
`GST_LEVEL_DEBUG` | Debugging messages should be used when something common happens that is not the expected default behavior, or something that's useful to know but doesn't happen all the time (ie. per loop iteration or buffer processed or event handled). An example would be notifications about state changes or receiving/sending of events.
`GST_LEVEL_LOG` | Log messages are messages that are very common but might be useful to know. As a rule of thumb a pipeline that is iterating as expected should never output anything else but LOG messages. Use this log level to log recurring information in chain functions and loop functions, for example.
`GST_LEVEL_TRACE` | Tracing-related messages (Since: 0.10.30) Examples for this are referencing/dereferencing of objects.
`GST_LEVEL_MEMDUMP` | memory dump messages are used to log (small) chunks of data as memory dumps in the log. They will be displayed as hexdump with ASCII characters. (Since: 0.10.23)
`GST_LEVEL_COUNT` | The number of defined debugging levels.

### GST_LEVEL_DEFAULT

    #define GST_LEVEL_DEFAULT GST_LEVEL_NONE

Defines the default debugging level to be used with GStreamer. It is normally set to GST_LEVEL_NONE so nothing get printed. As it can be configured at compile time, developer builds may chose to override that though. You can use this as an argument to `gst_debug_set_default_threshold()` to reset the debugging output to default behaviour.

### enum GstDebugColorFlags

    typedef enum {
      /* colors */
      GST_DEBUG_FG_BLACK		= 0x0000,
      GST_DEBUG_FG_RED		= 0x0001,
      GST_DEBUG_FG_GREEN		= 0x0002,
      GST_DEBUG_FG_YELLOW		= 0x0003,
      GST_DEBUG_FG_BLUE		= 0x0004,
      GST_DEBUG_FG_MAGENTA		= 0x0005,
      GST_DEBUG_FG_CYAN		= 0x0006,
      GST_DEBUG_FG_WHITE		= 0x0007,
      /* background colors */
      GST_DEBUG_BG_BLACK		= 0x0000,
      GST_DEBUG_BG_RED		= 0x0010,
      GST_DEBUG_BG_GREEN		= 0x0020,
      GST_DEBUG_BG_YELLOW		= 0x0030,
      GST_DEBUG_BG_BLUE		= 0x0040,
      GST_DEBUG_BG_MAGENTA		= 0x0050,
      GST_DEBUG_BG_CYAN		= 0x0060,
      GST_DEBUG_BG_WHITE		= 0x0070,
      /* other formats */
      GST_DEBUG_BOLD		= 0x0100,
      GST_DEBUG_UNDERLINE		= 0x0200
    } GstDebugColorFlags;

These are some terminal style flags you can use when creating your debugging categories to make them stand out in debugging output.

`GST_DEBUG_FG_BLACK` | Use black as foreground color.
`GST_DEBUG_FG_RED` | Use red as foreground color.
`GST_DEBUG_FG_GREEN` | Use green as foreground color.
`GST_DEBUG_FG_YELLOW` | Use yellow as foreground color.
`GST_DEBUG_FG_BLUE` | Use blue as foreground color.
`GST_DEBUG_FG_MAGENTA` | Use magenta as foreground color.
`GST_DEBUG_FG_CYAN` | Use cyan as foreground color.
`GST_DEBUG_FG_WHITE` | Use white as foreground color.
`GST_DEBUG_BG_BLACK` | Use black as background color.
`GST_DEBUG_BG_RED` | Use red as background color.
`GST_DEBUG_BG_GREEN` | Use green as background color.
`GST_DEBUG_BG_YELLOW` | Use yellow as background color.
`GST_DEBUG_BG_BLUE` | Use blue as background color.
`GST_DEBUG_BG_MAGENTA` | Use magenta as background color.
`GST_DEBUG_BG_CYAN` | Use cyan as background color.
`GST_DEBUG_BG_WHITE` | Use white as background color.
`GST_DEBUG_BOLD` | Make the output bold.
`GST_DEBUG_UNDERLINE` | Underline the output.

### struct GstDebugCategory

    struct GstDebugCategory {
    };

This is the struct that describes the categories. Once initialized with GST_DEBUG_CATEGORY_INIT, its values can't be changed anymore.

### enum GstDebugGraphDetails

    typedef enum {
      GST_DEBUG_GRAPH_SHOW_MEDIA_TYPE         = (1<<0),
      GST_DEBUG_GRAPH_SHOW_CAPS_DETAILS       = (1<<1),
      GST_DEBUG_GRAPH_SHOW_NON_DEFAULT_PARAMS = (1<<2),
      GST_DEBUG_GRAPH_SHOW_STATES             = (1<<3),
      GST_DEBUG_GRAPH_SHOW_ALL                = ((1<<4)-1)
    } GstDebugGraphDetails;

Available details for pipeline graphs produced by `GST_DEBUG_BIN_TO_DOT_FILE()` and `GST_DEBUG_BIN_TO_DOT_FILE_WITH_TS()`.

`GST_DEBUG_GRAPH_SHOW_MEDIA_TYPE` | show caps-name on edges
`GST_DEBUG_GRAPH_SHOW_CAPS_DETAILS` | show caps-details on edges
`GST_DEBUG_GRAPH_SHOW_NON_DEFAULT_PARAMS` | show modified parameters on elements
`GST_DEBUG_GRAPH_SHOW_STATES` | show element states
`GST_DEBUG_GRAPH_SHOW_ALL` | show all details

Since 0.10.15

### GST_STR_NULL()

    #define GST_STR_NULL(str) ((str) ? (str) : "(NULL)")

Macro to use when a string must not be NULL, but may be NULL. If the string is NULL, "(NULL)" is printed instead. In GStreamer printf string arguments may not be NULL, because on some platforms (ie Solaris) the libc crashes in that case. This includes debugging strings.

`str` : | The string to check.

### GST_DEBUG_PAD_NAME()

    #define             GST_DEBUG_PAD_NAME(pad)

Evaluates to 2 strings, that describe the pad. Often used in debugging statements.

`pad` : | The pad to debug.

### GST_FUNCTION

    #  define GST_FUNCTION     ((const char*) (__FUNCTION__))

This macro should evaluate to the name of the current function and be should be defined when configuring your project, as it is compiler dependant. If it is not defined, some default value is used. It is used to provide debugging output with the function name of the message.

Note that this is different from G_STRFUNC as we do not want the full function signature in C++ code.

### GstLogFunction ()

    void                (*GstLogFunction)                   (GstDebugCategory *category,
                                                             GstDebugLevel level,
                                                             const gchar *file,
                                                             const gchar *function,
                                                             gint line,
                                                             GObject *object,
                                                             GstDebugMessage *message,
                                                             gpointer data);

Function prototype for a logging function that can be registered with `gst_debug_add_log_function()`. Use G_GNUC_NO_INSTRUMENT on that function.

`category` : | a GstDebugCategory
`level` : | a GstDebugLevel
`file` : | file name
`function` : | function name
`line` : | line number
`object` : | a GObject
`message` : | the message
`data` : | user data for the log function

### gst_debug_log ()

    void                gst_debug_log                       (GstDebugCategory *category,
                                                             GstDebugLevel level,
                                                             const gchar *file,
                                                             const gchar *function,
                                                             gint line,
                                                             GObject *object,
                                                             const gchar *format,
                                                             ...);

Logs the given message using the currently registered debugging handlers.

`category` : | category to log
`level` : | level of the message is in
`file` : | the file that emitted the message, usually the __FILE__ identifier
`function` : | the function that emitted the message
`line` : | the line from that the message was emitted, usually __LINE__
`object` : | the object this message relates to, or NULL if none. [transfer none][allow-none]
`format` : | a printf style format string
`...` : | optional arguments for the format

### gst_debug_log_valist ()

    void                gst_debug_log_valist                (GstDebugCategory *category,
                                                             GstDebugLevel level,
                                                             const gchar *file,
                                                             const gchar *function,
                                                             gint line,
                                                             GObject *object,
                                                             const gchar *format,
                                                             va_list args);

Logs the given message using the currently registered debugging handlers.

`category` : | category to log
`level` : | level of the message is in
`file` : | the file that emitted the message, usually the __FILE__ identifier
`function` : | the function that emitted the message
`line` : | the line from that the message was emitted, usually __LINE__
`object` : | the object this message relates to, or NULL if none. [transfer none][allow-none]
`format` : | a printf style format string
`args` : | optional arguments for the format

### gst_debug_message_get ()

    const gchar *       gst_debug_message_get               (GstDebugMessage *message);

Gets the string representation of a GstDebugMessage. This function is used in debug handlers to extract the message.

`message` : | a debug message
Returns : | the string representation of a GstDebugMessage.

### gst_debug_log_default ()

    void                gst_debug_log_default               (GstDebugCategory *category,
                                                             GstDebugLevel level,
                                                             const gchar *file,
                                                             const gchar *function,
                                                             gint line,
                                                             GObject *object,
                                                             GstDebugMessage *message,
                                                             gpointer unused);

The default logging handler used by GStreamer. Logging functions get called whenever a macro like GST_DEBUG or similar is used. This function outputs the message and additional info to stderr (or the log file specified via the GST_DEBUG_FILE environment variable).

You can add other handlers by using `gst_debug_add_log_function()`. And you can remove this handler by calling gst_debug_remove_log_function(gst_debug_log_default);

`category` : | category to log
`level` : | level of the message
`file` : | the file that emitted the message, usually the __FILE__ identifier
`function` : | the function that emitted the message
`line` : | the line from that the message was emitted, usually __LINE__
`message` : | the actual message
`object` : | the object this message relates to, or NULL if none. [transfer none][allow-none]
`unused` : | an unused variable, reserved for some user_data.

### gst_debug_level_get_name ()

    const gchar *       gst_debug_level_get_name            (GstDebugLevel level);

Get the string representation of a debugging level

`level` : | the level to get the name for
Returns : | the name

### gst_debug_add_log_function ()

    void                gst_debug_add_log_function          (GstLogFunction func,
                                                             gpointer data);

Adds the logging function to the list of logging functions. Be sure to use G_GNUC_NO_INSTRUMENT on that function, it is needed.

`func` : | the function to use
`data` : | user data. [closure]

### gst_debug_remove_log_function ()

    guint               gst_debug_remove_log_function       (GstLogFunction func);

Removes all registered instances of the given logging functions.

`func` : | the log function to remove
Returns : | How many instances of the function were removed

### gst_debug_remove_log_function_by_data ()

    guint               gst_debug_remove_log_function_by_data
                                                            (gpointer data);

Removes all registered instances of log functions with the given user data.

`data` : | user data of the log function to remove
Returns : | How many instances of the function were removed

### gst_debug_set_active ()

    void                gst_debug_set_active                (gboolean active);

If activated, debugging messages are sent to the debugging handlers. It makes sense to deactivate it for speed issues.

### Note

This function is not threadsafe. It makes sense to only call it during initialization.

`active` : | Whether to use debugging output or not

### gst_debug_is_active ()

    gboolean            gst_debug_is_active                 (void);

Checks if debugging output is activated.

Returns : | TRUE, if debugging is activated

### gst_debug_set_colored ()

    void                gst_debug_set_colored               (gboolean colored);

Sets or unsets the use of coloured debugging output.

This function may be called before `gst_init()`.

`colored` : | Whether to use colored output or not

### gst_debug_is_colored ()

    gboolean            gst_debug_is_colored                (void);

Checks if the debugging output should be colored.

Returns : | TRUE, if the debug output should be colored.

### gst_debug_set_default_threshold ()

    void                gst_debug_set_default_threshold     (GstDebugLevel level);

Sets the default threshold to the given level and updates all categories to use this threshold.

This function may be called before `gst_init()`.

`level` : | level to set

### gst_debug_get_default_threshold ()

    GstDebugLevel       gst_debug_get_default_threshold     (void);

Returns the default threshold that is used for new categories.

Returns : | the default threshold level

### gst_debug_set_threshold_for_name ()

    void                gst_debug_set_threshold_for_name    (const gchar *name,
                                                             GstDebugLevel level);

Sets all categories which match the given glob style pattern to the given level.

`name` : | name of the categories to set
`level` : | level to set them to

### gst_debug_unset_threshold_for_name ()

    void                gst_debug_unset_threshold_for_name  (const gchar *name);

Resets all categories with the given name back to the default level.

`name` : | name of the categories to set

### GST_DEBUG_CATEGORY()

    #define GST_DEBUG_CATEGORY(cat) GstDebugCategory *cat = NULL

Defines a GstDebugCategory variable. This macro expands to nothing if debugging is disabled.

`cat` : | the category

### GST_DEBUG_CATEGORY_EXTERN()

    #define GST_DEBUG_CATEGORY_EXTERN(cat) extern GstDebugCategory *cat

Declares a GstDebugCategory variable as extern. Use in header files. This macro expands to nothing if debugging is disabled.

`cat` : | the category

### GST_DEBUG_CATEGORY_STATIC()

    #define GST_DEBUG_CATEGORY_STATIC(cat) static GstDebugCategory *cat = NULL

Defines a static GstDebugCategory variable. This macro expands to nothing if debugging is disabled.

`cat` : | the category

### GST_DEBUG_CATEGORY_INIT()

    #define             GST_DEBUG_CATEGORY_INIT(cat,name,color,description)

Initializes a new GstDebugCategory with the given properties and set to the default threshold.

### Note

This macro expands to nothing if debugging is disabled.

When naming your category, please follow the following conventions to ensure that the pattern matching for categories works as expected. It is not earth-shattering if you don't follow these conventions, but it would be nice for everyone.

If you define a category for a plugin or a feature of it, name the category like the feature. So if you wanted to write a "filesrc" element, you would name the category "filesrc". Use lowercase letters only. If you define more than one category for the same element, append an underscore and an identifier to your categories, like this: "filesrc_cache"

If you create a library or an application using debugging categories, use a common prefix followed by an underscore for all your categories. GStreamer uses the GST prefix so GStreamer categories look like "GST_STATES". Be sure to include uppercase letters.

`cat` : | the category to initialize.
`name` : | the name of the category.
`color` : | the colors to use for a color representation or 0 for no color.
`description` : | optional description of the category.

### GST_DEBUG_CATEGORY_GET()

    #define             GST_DEBUG_CATEGORY_GET(cat,name)

Looks up an existing GstDebugCategory by its `name` and sets `cat`. If the category is not found, but GST_CAT_DEFAULT is defined, that is assigned to `cat`. Otherwise `cat` will be NULL.

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    GST_DEBUG_CATEGORY_STATIC (gst_myplugin_debug);
    #define GST_CAT_DEFAULT gst_myplugin_debug
    GST_DEBUG_CATEGORY_STATIC (GST_CAT_PERFORMANCE);
    ...
    GST_DEBUG_CATEGORY_INIT (gst_myplugin_debug, "myplugin", 0, "nice element");
    GST_DEBUG_CATEGORY_GET (GST_CAT_PERFORMANCE, "GST_PERFORMANCE");

`cat` : | the category to initialize.
`name` : | log category name

Since 0.10.24

### gst_debug_category_free ()

    void                gst_debug_category_free             (GstDebugCategory *category);

Removes and frees the category and all associated resources.

`category` : | GstDebugCategory to free.

### gst_debug_category_set_threshold ()

    void                gst_debug_category_set_threshold    (GstDebugCategory *category,
                                                             GstDebugLevel level);

Sets the threshold of the category to the given level. Debug information will only be output if the threshold is lower or equal to the level of the debugging message.

### Note

Do not use this function in production code, because other functions may change the threshold of categories as side effect. It is however a nice function to use when debugging (even from gdb).

`category` : | a GstDebugCategory to set threshold of.
`level` : | the GstDebugLevel threshold to set.

### gst_debug_category_reset_threshold ()

    void                gst_debug_category_reset_threshold  (GstDebugCategory *category);

Resets the threshold of the category to the default level. Debug information will only be output if the threshold is lower or equal to the level of the debugging message. Use this function to set the threshold back to where it was after using `gst_debug_category_set_threshold()`.

`category` : | a GstDebugCategory to reset threshold of.

### gst_debug_category_get_threshold ()

    GstDebugLevel       gst_debug_category_get_threshold    (GstDebugCategory *category);

Returns the threshold of a GstDebugCategory.

`category` : | a GstDebugCategory to get threshold of.
Returns : | the GstDebugLevel that is used as threshold.

### gst_debug_category_get_name ()

    const gchar *       gst_debug_category_get_name         (GstDebugCategory *category);

Returns the name of a debug category.

`category` : | a GstDebugCategory to get name of.
Returns : | the name of the category.

### gst_debug_category_get_color ()

    guint               gst_debug_category_get_color        (GstDebugCategory *category);

Returns the color of a debug category used when printing output in this category.

`category` : | a GstDebugCategory to get the color of.
Returns : | the color of the category.

### gst_debug_category_get_description ()

    const gchar *       gst_debug_category_get_description  (GstDebugCategory *category);

Returns the description of a debug category.

`category` : | a GstDebugCategory to get the description of.
Returns : | the description of the category.

### gst_debug_get_all_categories ()

    GSList *            gst_debug_get_all_categories        (void);

Returns a snapshot of a all categories that are currently in use . This list may change anytime. The caller has to free the list after use.

Returns : | the list of debug categories. [transfer container][element-type Gst.DebugCategory]

### gst_debug_construct_term_color ()

    gchar *             gst_debug_construct_term_color      (guint colorinfo);

Constructs a string that can be used for getting the desired color in color terminals. You need to free the string after use.

`colorinfo` : | the color info
Returns : | a string containing the color definition. [transfer full][type gchar*]

### gst_debug_construct_win_color ()

    gint                gst_debug_construct_win_color       (guint colorinfo);

Constructs an integer that can be used for getting the desired color in windows' terminals (cmd.exe). As there is no mean to underline, we simply ignore this attribute.

This function returns 0 on non-windows machines.

`colorinfo` : | the color info
Returns : | an integer containing the color definition

Since 0.10.23

### GST_CAT_LEVEL_LOG()

    #define             GST_CAT_LEVEL_LOG(cat,level,object,...)

Outputs a debugging message. This is the most general macro for outputting debugging messages. You will probably want to use one of the ones described below.

`cat` : | category to use
`level` : | the severity of the message
`object` : | the GObject the message belongs to or NULL if none
`...` : | A printf-style message to output

### GST_CAT_ERROR_OBJECT()

    #define GST_CAT_ERROR_OBJECT(cat,obj,...) GST_CAT_LEVEL_LOG (cat, GST_LEVEL_ERROR,   obj,  __VA_ARGS__)

Output an error message belonging to the given object in the given category.

`cat` : | category to use
`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_CAT_WARNING_OBJECT()

    #define GST_CAT_WARNING_OBJECT(cat,obj,...) GST_CAT_LEVEL_LOG (cat, GST_LEVEL_WARNING, obj,  __VA_ARGS__)

Output a warning message belonging to the given object in the given category.

`cat` : | category to use
`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_CAT_INFO_OBJECT()

    #define GST_CAT_INFO_OBJECT(cat,obj,...) GST_CAT_LEVEL_LOG (cat, GST_LEVEL_INFO,    obj,  __VA_ARGS__)

Output an informational message belonging to the given object in the given category.

`cat` : | category to use
`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_CAT_DEBUG_OBJECT()

    #define GST_CAT_DEBUG_OBJECT(cat,obj,...) GST_CAT_LEVEL_LOG (cat, GST_LEVEL_DEBUG,   obj,  __VA_ARGS__)

Output an debugging message belonging to the given object in the given category.

`cat` : | category to use
`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_CAT_LOG_OBJECT()

    #define GST_CAT_LOG_OBJECT(cat,obj,...)		GST_CAT_LEVEL_LOG (cat, GST_LEVEL_LOG,     obj,  __VA_ARGS__)

Output an logging message belonging to the given object in the given category.

`cat` : | category to use
`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_CAT_FIXME_OBJECT()

    #define GST_CAT_FIXME_OBJECT(cat,obj,...) GST_CAT_LEVEL_LOG (cat, GST_LEVEL_FIXME,   obj,  __VA_ARGS__)

Output a fixme message belonging to the given object in the given category.

`cat` : | category to use
`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

Since 0.10.23

### GST_CAT_TRACE_OBJECT()

    #define GST_CAT_TRACE_OBJECT(cat,obj,...) GST_CAT_LEVEL_LOG (cat, GST_LEVEL_TRACE,   obj,  __VA_ARGS__)

Output a tracing message belonging to the given object in the given category.

`cat` : | category to use
`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

Since 0.10.30

### GST_CAT_MEMDUMP_OBJECT()

    #define             GST_CAT_MEMDUMP_OBJECT(cat,obj,msg,data,length)

Output a hexdump of `data` relating to the given object in the given category.

`cat` : | category to use
`obj` : | the GObject the message belongs to
`msg` : | message string to log with the data
`data` : | pointer to the data to output
`length` : | length of the data to output

Since 0.10.23

### GST_CAT_ERROR()

    #define GST_CAT_ERROR(cat,...)			GST_CAT_LEVEL_LOG (cat, GST_LEVEL_ERROR,   NULL, __VA_ARGS__)

Output an error message in the given category.

`cat` : | category to use
`...` : | printf-style message to output

### GST_CAT_WARNING()

    #define GST_CAT_WARNING(cat,...)		GST_CAT_LEVEL_LOG (cat, GST_LEVEL_WARNING, NULL, __VA_ARGS__)

Output an warning message in the given category.

`cat` : | category to use
`...` : | printf-style message to output

### GST_CAT_INFO()

    #define GST_CAT_INFO(cat,...)			GST_CAT_LEVEL_LOG (cat, GST_LEVEL_INFO,    NULL, __VA_ARGS__)

Output an informational message in the given category.

`cat` : | category to use
`...` : | printf-style message to output

### GST_CAT_DEBUG()

    #define GST_CAT_DEBUG(cat,...)			GST_CAT_LEVEL_LOG (cat, GST_LEVEL_DEBUG,   NULL, __VA_ARGS__)

Output an debugging message in the given category.

`cat` : | category to use
`...` : | printf-style message to output

### GST_CAT_LOG()

    #define GST_CAT_LOG(cat,...)			GST_CAT_LEVEL_LOG (cat, GST_LEVEL_LOG,     NULL, __VA_ARGS__)

Output an logging message in the given category.

`cat` : | category to use
`...` : | printf-style message to output

### GST_CAT_FIXME()

    #define GST_CAT_FIXME(cat,...)			GST_CAT_LEVEL_LOG (cat, GST_LEVEL_FIXME,   NULL, __VA_ARGS__)

Output an fixme message in the given category.

`cat` : | category to use
`...` : | printf-style message to output

Since 0.10.23

### GST_CAT_TRACE()

    #define GST_CAT_TRACE(cat,...)		GST_CAT_LEVEL_LOG (cat, GST_LEVEL_TRACE,   NULL, __VA_ARGS__)

Output a tracing message in the given category.

`cat` : | category to use
`...` : | printf-style message to output

Since 0.10.30

### GST_CAT_MEMDUMP()

    #define             GST_CAT_MEMDUMP(cat,msg,data,length)

Output a hexdump of `data` in the given category.

`cat` : | category to use
`msg` : | message string to log with the data
`data` : | pointer to the data to output
`length` : | length of the data to output

Since 0.10.23

### GST_ERROR_OBJECT()

    #define GST_ERROR_OBJECT(obj,...) GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_ERROR,   obj,  __VA_ARGS__)

Output an error message belonging to the given object in the default category.

`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_WARNING_OBJECT()

    #define GST_WARNING_OBJECT(obj,...) GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_WARNING, obj,  __VA_ARGS__)

Output a warning message belonging to the given object in the default category.

`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_INFO_OBJECT()

    #define GST_INFO_OBJECT(obj,...) GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_INFO,    obj,  __VA_ARGS__)

Output an informational message belonging to the given object in the default category.

`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_DEBUG_OBJECT()

    #define GST_DEBUG_OBJECT(obj,...) GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_DEBUG,   obj,  __VA_ARGS__)

Output a debugging message belonging to the given object in the default category.

`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_LOG_OBJECT()

    #define GST_LOG_OBJECT(obj,...)		GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_LOG,     obj,  __VA_ARGS__)

Output a logging message belonging to the given object in the default category.

`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

### GST_FIXME_OBJECT()

    #define GST_FIXME_OBJECT(obj,...) GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_FIXME,   obj,  __VA_ARGS__)

Output a fixme message belonging to the given object in the default category.

`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

Since 0.10.23

### GST_TRACE_OBJECT()

    #define GST_TRACE_OBJECT(obj,...) GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_TRACE,   obj,  __VA_ARGS__)

Output a tracing message belonging to the given object in the default category.

`obj` : | the GObject the message belongs to
`...` : | printf-style message to output

Since 0.10.30

### GST_MEMDUMP_OBJECT()

    #define             GST_MEMDUMP_OBJECT(obj,msg,data,length)

Output a logging message belonging to the given object in the default category.

`obj` : | the GObject the message belongs to
`msg` : | message string to log with the data
`data` : | pointer to the data to output
`length` : | length of the data to output

Since 0.10.23

### GST_ERROR()

    #define GST_ERROR(...)			GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_ERROR,   NULL, __VA_ARGS__)

Output an error message in the default category.

`...` : | printf-style message to output

### GST_WARNING()

    #define GST_WARNING(...)		GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_WARNING, NULL, __VA_ARGS__)

Output a warning message in the default category.

`...` : | printf-style message to output

### GST_INFO()

    #define GST_INFO(...)			GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_INFO,    NULL, __VA_ARGS__)

Output an informational message in the default category.

`...` : | printf-style message to output

### GST_DEBUG()

    #define GST_DEBUG(...)			GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_DEBUG,   NULL, __VA_ARGS__)

Output a debugging message in the default category.

`...` : | printf-style message to output

### GST_LOG()

    #define GST_LOG(...)			GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_LOG,     NULL, __VA_ARGS__)

Output a logging message in the default category.

`...` : | printf-style message to output

### GST_FIXME()

    #define GST_FIXME(...)			GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_FIXME,   NULL, __VA_ARGS__)

Output a fixme message in the default category.

`...` : | printf-style message to output

Since 0.10.23

### GST_TRACE()

    #define GST_TRACE(...)		GST_CAT_LEVEL_LOG (GST_CAT_DEFAULT, GST_LEVEL_TRACE,   NULL, __VA_ARGS__)

Output a tracing message in the default category.

`...` : | printf-style message to output

Since 0.10.30

### GST_MEMDUMP()

    #define             GST_MEMDUMP(msg,data,length)

Output a hexdump of `data`.

`msg` : | message string to log with the data
`data` : | pointer to the data to output
`length` : | length of the data to output

Since 0.10.23

### GST_DEBUG_REGISTER_FUNCPTR()

    #define             GST_DEBUG_REGISTER_FUNCPTR(ptr)

Register a pointer to a function with its name, so it can later be used by `GST_DEBUG_FUNCPTR_NAME()`.

Use this variant of GST_DEBUG_FUNCPTR if you do not need to use `ptr`.

`ptr` : | pointer to the function to register

Since 0.10.26

### GST_DEBUG_FUNCPTR()

    #define             GST_DEBUG_FUNCPTR(ptr)

Register a pointer to a function with its name, so it can later be used by `GST_DEBUG_FUNCPTR_NAME()`.

`ptr` : | pointer to the function to register
Returns : | the value passed to `ptr`.

### GST_DEBUG_FUNCPTR_NAME()

    #define             GST_DEBUG_FUNCPTR_NAME(ptr)

Retrieves the name of the function, if it was previously registered with `GST_DEBUG_FUNCPTR()`. If not, it returns a description of the pointer.

This macro returns a constant string which must not be modified or freed by the caller.

`ptr` : | address of the function of which to look up the name

### GST_DEBUG_BIN_TO_DOT_FILE()

    #define GST_DEBUG_BIN_TO_DOT_FILE(bin, details, file_name) gst_debug_bin_to_dot_file (bin, details, file_name)

To aid debugging applications one can use this method to write out the whole network of gstreamer elements that form the pipeline into an dot file. This file can be processed with graphviz to get an image.

    1
    dot -Tpng -oimage.png graph_lowlevel.dot

The macro is only active if gstreamer is configured with "--gst-enable-gst-debug" and the environment variable GST_DEBUG_DUMP_DOT_DIR is set to a basepath (e.g. /tmp).

`bin` : | the top-level pipeline that should be analyzed
`details` : | details to show in the graph, e.g. GST_DEBUG_GRAPH_SHOW_ALL or one or more other GstDebugGraphDetails flags.
`file_name` : | output base filename (e.g. "myplayer")

Since 0.10.15

### GST_DEBUG_BIN_TO_DOT_FILE_WITH_TS()

    #define GST_DEBUG_BIN_TO_DOT_FILE_WITH_TS(bin, details, file_name) gst_debug_bin_to_dot_file_with_ts (bin, details, file_name)

This works like `GST_DEBUG_BIN_TO_DOT_FILE()`, but adds the current timestamp to the filename, so that it can be used to take multiple snapshots.

`bin` : | the top-level pipeline that should be analyzed
`details` : | details to show in the graph, e.g. GST_DEBUG_GRAPH_SHOW_ALL or one or more other GstDebugGraphDetails flags.
`file_name` : | output base filename (e.g. "myplayer")

Since 0.10.15

### gst_debug_print_stack_trace ()

    void                gst_debug_print_stack_trace         (void);

If GST_ENABLE_FUNC_INSTRUMENTATION is defined a stacktrace is available for gstreamer code, which can be printed with this function.

### GST_TIME_FORMAT

    #define GST_TIME_FORMAT "u:%02u:%02u.%09u"

A string that can be used in printf-like format strings to display a GstClockTime value in h:m:s format. Use `GST_TIME_ARGS()` to construct the matching arguments.

Example:

    1
    printf("%" GST_TIME_FORMAT "\n", GST_TIME_ARGS(ts));

### GST_TIME_ARGS()

    #define             GST_TIME_ARGS(t)

Format `t` for the GST_TIME_FORMAT format string. Note: `t` will be evaluated more than once.

`t` : | a GstClockTime

### gst_debug_bin_to_dot_file ()

    void                gst_debug_bin_to_dot_file           (GstBin *bin,
                                                             GstDebugGraphDetails details,
                                                             const gchar *file_name);

### gst_debug_bin_to_dot_file_with_ts ()

    void                gst_debug_bin_to_dot_file_with_ts   (GstBin *bin,
                                                             GstDebugGraphDetails details,
                                                             const gchar *file_name);

## See Also

gstreamer-gstconfig, gstreamer-Gst for command line parameters and environment variables that affect the debugging output.