GstInfo: GStreamer 1.0 Core Reference Manual

## GstInfo GstInfo — Debugging and logging facilities |

## Functions

#define | GST_STR_NULL()
#define | GST_DEBUG_PAD_NAME()
void | (*GstLogFunction) ()
void | gst_debug_log ()
void | gst_debug_log_valist ()
const gchar * | gst_debug_message_get ()
void | gst_debug_log_default ()
const gchar * | gst_debug_level_get_name ()
void | gst_debug_add_log_function ()
guint | gst_debug_remove_log_function ()
guint | gst_debug_remove_log_function_by_data ()
void | gst_debug_set_active ()
gboolean | gst_debug_is_active ()
void | gst_debug_set_colored ()
void | gst_debug_set_color_mode ()
void | gst_debug_set_color_mode_from_string ()
gboolean | gst_debug_is_colored ()
GstDebugColorMode | gst_debug_get_color_mode ()
void | gst_debug_set_default_threshold ()
void | gst_debug_set_threshold_from_string ()
GstDebugLevel | gst_debug_get_default_threshold ()
void | gst_debug_set_threshold_for_name ()
void | gst_debug_unset_threshold_for_name ()
#define | GST_DEBUG_CATEGORY()
#define | GST_DEBUG_CATEGORY_EXTERN()
#define | GST_DEBUG_CATEGORY_STATIC()
#define | GST_DEBUG_CATEGORY_INIT()
#define | GST_DEBUG_CATEGORY_GET()
void | gst_debug_category_free ()
void | gst_debug_category_set_threshold ()
void | gst_debug_category_reset_threshold ()
GstDebugLevel | gst_debug_category_get_threshold ()
const gchar * | gst_debug_category_get_name ()
guint | gst_debug_category_get_color ()
const gchar * | gst_debug_category_get_description ()
GSList * | gst_debug_get_all_categories ()
gchar * | gst_debug_construct_term_color ()
gint | gst_debug_construct_win_color ()
#define | GST_CAT_LEVEL_LOG()
#define | GST_CAT_ERROR_OBJECT()
#define | GST_CAT_WARNING_OBJECT()
#define | GST_CAT_INFO_OBJECT()
#define | GST_CAT_DEBUG_OBJECT()
#define | GST_CAT_LOG_OBJECT()
#define | GST_CAT_FIXME_OBJECT()
#define | GST_CAT_TRACE_OBJECT()
#define | GST_CAT_MEMDUMP_OBJECT()
#define | GST_CAT_ERROR()
#define | GST_CAT_WARNING()
#define | GST_CAT_INFO()
#define | GST_CAT_DEBUG()
#define | GST_CAT_LOG()
#define | GST_CAT_FIXME()
#define | GST_CAT_TRACE()
#define | GST_CAT_MEMDUMP()
#define | GST_ERROR_OBJECT()
#define | GST_WARNING_OBJECT()
#define | GST_INFO_OBJECT()
#define | GST_DEBUG_OBJECT()
#define | GST_LOG_OBJECT()
#define | GST_FIXME_OBJECT()
#define | GST_TRACE_OBJECT()
#define | GST_MEMDUMP_OBJECT()
#define | GST_ERROR()
#define | GST_WARNING()
#define | GST_INFO()
#define | GST_DEBUG()
#define | GST_LOG()
#define | GST_FIXME()
#define | GST_TRACE()
#define | GST_MEMDUMP()
#define | GST_DEBUG_REGISTER_FUNCPTR()
#define | GST_DEBUG_FUNCPTR()
#define | GST_DEBUG_FUNCPTR_NAME()
#define | GST_DEBUG_BIN_TO_DOT_FILE()
#define | GST_DEBUG_BIN_TO_DOT_FILE_WITH_TS()
void | gst_debug_print_stack_trace ()
#define | GST_TIME_ARGS()
#define | GST_STIME_ARGS()
gchar * | gst_debug_bin_to_dot_data ()
void | gst_debug_bin_to_dot_file ()
void | gst_debug_bin_to_dot_file_with_ts ()
gint | gst_info_vasprintf ()
gchar * | gst_info_strdup_vprintf ()
gchar * | gst_info_strdup_printf ()

## Types and Values

enum | GstDebugLevel
#define | GST_LEVEL_DEFAULT
#define | GST_LEVEL_MAX
enum | GstDebugColorFlags
enum | GstDebugColorMode
struct | GstDebugCategory
enum | GstDebugGraphDetails
#define | GST_FUNCTION
extern | GST_CAT_DEFAULT
#define | GST_TIME_FORMAT
#define | GST_STIME_FORMAT
#define | GST_PTR_FORMAT
#define | GST_SEGMENT_FORMAT

## Includes

    #include <gst/gst.h>

## 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()`.

## Functions

### 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.

#### Parameters

str | The string to check. | [allow-none]

### GST_DEBUG_PAD_NAME()

    #define             GST_DEBUG_PAD_NAME(pad)

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

#### Parameters

pad | The pad to debug. |

### GstLogFunction ()

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

#### Parameters

category | a GstDebugCategory |
level | a GstDebugLevel |
file | file name |
function | function name |
line | line number |
object | a GObject |
message | the message |
user_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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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 user_data);

The default logging handler used by GStreamer. Logging functions get called whenever a macro like GST_DEBUG or similar is used. By default this function is setup to output the message and additional info to stderr (or the log file specified via the GST_DEBUG_FILE environment variable) as received via `user_data` .

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);

#### Parameters

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]
user_data | the FILE* to log to |

### gst_debug_level_get_name ()

    const gchar *
    gst_debug_level_get_name (GstDebugLevel level);

Get the string representation of a debugging level

#### Parameters

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 user_data,
                                GDestroyNotify notify);

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

#### Parameters

func | the function to use |
user_data | user data |
notify | called when `user_data` is not used anymore |

### gst_debug_remove_log_function ()

    guint
    gst_debug_remove_log_function (GstLogFunction func);

Removes all registered instances of the given logging functions.

#### Parameters

func | the log function to remove, or `NULL` to remove the default log function. | [scope call][allow-none]

#### 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.

#### Parameters

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.

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

#### Parameters

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. Same as `gst_debug_set_color_mode()` with the argument being being GST_DEBUG_COLOR_MODE_ON or GST_DEBUG_COLOR_MODE_OFF.

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

#### Parameters

colored | Whether to use colored output or not |

### gst_debug_set_color_mode ()

    void
    gst_debug_set_color_mode (GstDebugColorMode mode);

Changes the coloring mode for debug output.

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

#### Parameters

mode | The coloring mode for debug output. See `GstDebugColorMode` . |

Since: 1.2

### gst_debug_set_color_mode_from_string ()

    void
    gst_debug_set_color_mode_from_string (const gchar *mode);

Changes the coloring mode for debug output.

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

#### Parameters

mode | The coloring mode for debug output. One of the following: "on", "auto", "off", "disable", "unix". |

Since: 1.2

### 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_get_color_mode ()

    GstDebugColorMode
    gst_debug_get_color_mode (void);

Changes the coloring mode for debug output.

#### Returns

see `GstDebugColorMode` for possible values.

Since: 1.2

### 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()`.

#### Parameters

level | level to set |

### gst_debug_set_threshold_from_string ()

    void
    gst_debug_set_threshold_from_string (const gchar *list,
                                         gboolean reset);

Sets the debug logging wanted in the same form as with the GST_DEBUG environment variable. You can use wildcards such as '*', but note that the order matters when you use wild cards, e.g. "foosrc:6,*src:3,*:2" sets everything to log level 2.

#### Parameters

list | comma-separated list of "category:level" pairs to be used as debug logging levels |
reset | `TRUE` to clear all previously-set debug levels before setting new thresholds `FALSE` if adding the threshold described by `list` to the one already set. |

Since: 1.2

### 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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

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.

#### Parameters

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");

#### Parameters

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

### gst_debug_category_free ()

    void
    gst_debug_category_free (GstDebugCategory *category);

Removes and frees the category and all associated resources.

#### Parameters

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.

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).

#### Parameters

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()`.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

colorinfo | the color info |

#### Returns

an integer containing the color definition

### 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.

#### Parameters

cat | category to use |
level | the severity of the message |
object | the GObject the message belongs to or `NULL` if none. | [allow-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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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

### 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.

#### Parameters

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

### 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.

#### Parameters

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 |

### 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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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

### 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.

#### Parameters

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

### GST_CAT_MEMDUMP()

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

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

#### Parameters

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 |

### 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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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.

#### Parameters

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

### 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.

#### Parameters

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

### GST_MEMDUMP_OBJECT()

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

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

#### Parameters

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 |

### 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.

#### Parameters

... | 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.

#### Parameters

... | 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.

#### Parameters

... | 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.

#### Parameters

... | 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.

#### Parameters

... | 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.

#### Parameters

... | printf-style message to output |

### 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.

#### Parameters

... | printf-style message to output |

### GST_MEMDUMP()

    #define             GST_MEMDUMP(msg,data,length)

Output a hexdump of `data` .

#### Parameters

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

### 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` .

#### Parameters

ptr | pointer to the function to register |

### 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()`.

#### Parameters

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.

#### Parameters

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, like this:

    1
    dot -Tpng -oimage.png graph_lowlevel.dot

There is also a utility called xdot which allows you to view the dot file directly without converting it first.

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).

#### Parameters

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") |

### 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.

#### Parameters

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") |

### 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_ARGS()

    #define             GST_TIME_ARGS(t)

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

#### Parameters

t | a GstClockTime |

### GST_STIME_ARGS()

    #define             GST_STIME_ARGS(t)

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

#### Parameters

t | a GstClockTimeDiff or gint64 |

Since: 1.6

### gst_debug_bin_to_dot_data ()

    gchar *
    gst_debug_bin_to_dot_data (GstBin *bin,
                               GstDebugGraphDetails details);

### 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);

### gst_info_vasprintf ()

    gint
    gst_info_vasprintf (gchar **result,
                        const gchar *format,
                        va_list args);

Allocates and fills a string large enough (including the terminating null byte) to hold the specified printf style `format` and `args` .

This function deals with the GStreamer specific printf specifiers GST_PTR_FORMAT and GST_SEGMENT_FORMAT. If you do not have these specifiers in your `format` string, you do not need to use this function and can use alternatives such as `g_vasprintf()`.

Free `result` with `g_free()`.

#### Parameters

result | the resulting string. | [out]
format | a printf style format string |
args | the va_list of printf arguments for `format` |

#### Returns

the length of the string allocated into `result` or -1 on any error

Since: 1.8

### gst_info_strdup_vprintf ()

    gchar *
    gst_info_strdup_vprintf (const gchar *format,
                             va_list args);

Allocates, fills and returns a null terminated string from the printf style `format` string and `args` .

See `gst_info_vasprintf()` for when this function is required.

Free with `g_free()`.

#### Parameters

format | a printf style format string |
args | the va_list of printf arguments for `format` |

#### Returns

a newly allocated null terminated string or `NULL` on any error

Since: 1.8

### gst_info_strdup_printf ()

    gchar *
    gst_info_strdup_printf (const gchar *format,
                            ...);

Allocates, fills and returns a null terminated string from the printf style `format` string and corresponding arguments.

See `gst_info_vasprintf()` for when this function is required.

Free with `g_free()`.

#### Parameters

format | a printf style format string |
... | the printf arguments for `format` |

#### Returns

a newly allocated null terminated string or `NULL` on any error

Since: 1.8

## Types and Values

### enum 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.

#### Members

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 occurred 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_error. |
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. |
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 running as expected should never output anything else but LOG messages whilst processing data. Use this log level to log recurring information in chain functions and loop functions, for example. |
GST_LEVEL_TRACE | Tracing-related messages. 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. |
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.

### GST_LEVEL_MAX

    #define GST_LEVEL_MAX GST_LEVEL_COUNT

Defines the maximum debugging level to be enabled at compilation time. By default it is set such that all debugging statements will be enabled.

If you wish to compile GStreamer and plugins with only some debugging statements (Such as just warnings and errors), you can define it at compile time to the maximum debug level. Any debug statements above that level will be compiled out.

Since: 1.6

### enum GstDebugColorFlags

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

#### Members

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. |

### enum GstDebugColorMode

#### Members

GST_DEBUG_COLOR_MODE_OFF | Do not use colors in logs. |
GST_DEBUG_COLOR_MODE_ON | Paint logs in a platform-specific way. |
GST_DEBUG_COLOR_MODE_UNIX | Paint logs with UNIX terminal color codes no matter what platform GStreamer is running on. |

### 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

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

#### Members

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_FULL_PARAMS | show full element parameter values even if they are very long |
GST_DEBUG_GRAPH_SHOW_ALL | show all the typical details that one might want |
GST_DEBUG_GRAPH_SHOW_VERBOSE | show all details regardless of how large or verbose they make the resulting output |

### GST_FUNCTION

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

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.

### GST_CAT_DEFAULT

    GST_EXPORT GstDebugCategory * GST_CAT_DEFAULT;

Default gstreamer core debug log category. Please define your own.

### 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_STIME_FORMAT

    #define GST_STIME_FORMAT "c%" GST_TIME_FORMAT

A string that can be used in printf-like format strings to display a signed GstClockTimeDiff or gint64 value in h:m:s format. Use `GST_TIME_ARGS()` to construct the matching arguments.

Example:

    1
    printf("%" GST_STIME_FORMAT "\n", GST_STIME_ARGS(ts));

Since: 1.6

### GST_PTR_FORMAT

    #define GST_PTR_FORMAT     "p\aA"

printf format type used to debug GStreamer types. You can use this in combination with GStreamer's debug logging system as well as the functions `gst_info_vasprintf()`, `gst_info_strdup_vprintf()` and `gst_info_strdup_printf()` to pretty-print the following types: GstCaps, GstStructure, GstCapsFeatures, GstTagList, GstDateTime, GstBuffer, GstBufferList, GstMessage, GstEvent, GstQuery, GstContext, GstPad, GstObject. All GObject types will be printed as typename plus pointer, and everything else will simply be printed as pointer address.

This can only be used on types whose size is >= sizeof(gpointer).

### GST_SEGMENT_FORMAT

    #define GST_SEGMENT_FORMAT "p\aB"

printf format type used to debug GStreamer segments. You can use this in combination with GStreamer's debug logging system as well as the functions `gst_info_vasprintf()`, `gst_info_strdup_vprintf()` and `gst_info_strdup_printf()` to pretty-print GstSegment structures. This can only be used on pointers to GstSegment structures.

## See Also

gst-running for command line parameters and environment variables that affect the debugging output.