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Elektra 0.11.0
Files | Typedefs | Functions
Notification

Notification feature. More...

Files

file  kdbnotification.h
 Elektra-Notification structures and declarations for application developers.
 
file  kdbnotificationinternal.h
 Elektra-Notification structures and declarations for developing notification and transport plugins.
 

Typedefs

typedef void(* ElektraNotificationConversionErrorCallback) (Key *key, void *context)
 Callback function called when string to number conversion failed. More...
 
typedef void(* ElektraNotificationChangeCallback) (Key *key, void *context)
 Callback function for key changes. More...
 

Functions

int elektraNotificationRegisterCallback (KDB *kdb, Key *key, ElektraNotificationChangeCallback callback, void *context)
 Subscribe for updates via callback when a given key value is changed. More...
 
int elektraNotificationRegisterCallbackSameOrBelow (KDB *kdb, Key *key, ElektraNotificationChangeCallback callback, void *context)
 Subscribe for updates via callback when a given key or a key below changed. More...
 
int elektraNotificationRegisterInt (KDB *kdb, Key *key, int *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterUnsignedInt (KDB *kdb, Key *key, unsigned int *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterLong (KDB *kdb, Key *key, long *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterUnsignedLong (KDB *kdb, Key *key, unsigned long *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterLongLong (KDB *kdb, Key *key, long long *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterUnsignedLongLong (KDB *kdb, Key *key, unsigned long long *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterFloat (KDB *kdb, Key *key, float *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterDouble (KDB *kdb, Key *key, double *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbBoolean (KDB *kdb, Key *key, kdb_boolean_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbChar (KDB *kdb, Key *key, kdb_char_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbOctet (KDB *kdb, Key *key, kdb_octet_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbShort (KDB *kdb, Key *key, kdb_short_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbUnsignedShort (KDB *kdb, Key *key, kdb_unsigned_short_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbLong (KDB *kdb, Key *key, kdb_long_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbUnsignedLong (KDB *kdb, Key *key, kdb_unsigned_long_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbLongLong (KDB *kdb, Key *key, kdb_long_long_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbUnsignedLongLong (KDB *kdb, Key *key, kdb_unsigned_long_long_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbFloat (KDB *kdb, Key *key, kdb_float_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 
int elektraNotificationRegisterKdbDouble (KDB *kdb, Key *key, kdb_double_t *variable)
 Subscribe for automatic updates to a given variable when the given key value is changed. More...
 

Detailed Description

Notification feature.

For an introduction to notifications please see the Notification Tutorial.

Examples:

Hook Setup

elektraNotificationContract() returns a contract for use with kdbOpen(). The contract ensures that the internalnotification plugin is registered into the correct hook and configured correctly.

Transport Plugins

Notification transport plugins (or simply transport plugins) need access to an I/O binding, as well as a notification callback and context.

All of these can be retrieved from the global keyset. The keys are as follows:

All of these keys are binary and store a pointer that can be read via *(TYPE **) keyValue (key).

The I/O binding can be accessed at any time. It is recommended, plugins read the key once during their open function and store the pointer in their plugin data struct.

The notification callback and context are provided by the internalnotification plugin. Since it might be initialised after the transport plugin, it is not recommended to read the callback and context in the open function. Instead the plugin should read and store the values when the first notification is processed.

Transport plugins should handle missing I/O bindings, notification callbacks and notification contexts gracefully. The plugin should not report and error and instead simply log a debug or warning message.

Typedef Documentation

◆ ElektraNotificationChangeCallback

typedef void(* ElektraNotificationChangeCallback) (Key *key, void *context)

Callback function for key changes.

Parameters
keychanged key
contextuser supplied callback context

◆ ElektraNotificationConversionErrorCallback

typedef void(* ElektraNotificationConversionErrorCallback) (Key *key, void *context)

Callback function called when string to number conversion failed.

Parameters
keykey with invalid value
contextuser supplied callback context

Function Documentation

◆ elektraNotificationRegisterCallback()

int elektraNotificationRegisterCallback ( KDB *  kdb,
Key *  key,
ElektraNotificationChangeCallback  callback,
void *  context 
)

Subscribe for updates via callback when a given key value is changed.

Parameters
handleplugin handle
keykey to watch for changes
callbackcallback function
contextuser supplied context passed to callback function
Return values
1on success
0on failure

◆ elektraNotificationRegisterCallbackSameOrBelow()

int elektraNotificationRegisterCallbackSameOrBelow ( KDB *  kdb,
Key *  key,
ElektraNotificationChangeCallback  callback,
void *  context 
)

Subscribe for updates via callback when a given key or a key below changed.

Parameters
handleplugin handle
keykey to watch for changes
callbackcallback function
contextuser supplied context passed to callback function
Return values
1on success
0on failure

◆ elektraNotificationRegisterDouble()

int elektraNotificationRegisterDouble ( KDB *  kdb,
Key *  key,
double *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterFloat()

int elektraNotificationRegisterFloat ( KDB *  kdb,
Key *  key,
float *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterInt()

int elektraNotificationRegisterInt ( KDB *  kdb,
Key *  key,
int *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

Subscribe for automatic updates to a given variable when the given key value is changed. On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbBoolean()

int elektraNotificationRegisterKdbBoolean ( KDB *  kdb,
Key *  key,
kdb_boolean_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbChar()

int elektraNotificationRegisterKdbChar ( KDB *  kdb,
Key *  key,
kdb_char_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbDouble()

int elektraNotificationRegisterKdbDouble ( KDB *  kdb,
Key *  key,
kdb_double_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbFloat()

int elektraNotificationRegisterKdbFloat ( KDB *  kdb,
Key *  key,
kdb_float_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbLong()

int elektraNotificationRegisterKdbLong ( KDB *  kdb,
Key *  key,
kdb_long_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbLongLong()

int elektraNotificationRegisterKdbLongLong ( KDB *  kdb,
Key *  key,
kdb_long_long_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbOctet()

int elektraNotificationRegisterKdbOctet ( KDB *  kdb,
Key *  key,
kdb_octet_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbShort()

int elektraNotificationRegisterKdbShort ( KDB *  kdb,
Key *  key,
kdb_short_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbUnsignedLong()

int elektraNotificationRegisterKdbUnsignedLong ( KDB *  kdb,
Key *  key,
kdb_unsigned_long_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbUnsignedLongLong()

int elektraNotificationRegisterKdbUnsignedLongLong ( KDB *  kdb,
Key *  key,
kdb_unsigned_long_long_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterKdbUnsignedShort()

int elektraNotificationRegisterKdbUnsignedShort ( KDB *  kdb,
Key *  key,
kdb_unsigned_short_t *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterLong()

int elektraNotificationRegisterLong ( KDB *  kdb,
Key *  key,
long *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterLongLong()

int elektraNotificationRegisterLongLong ( KDB *  kdb,
Key *  key,
long long *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterUnsignedInt()

int elektraNotificationRegisterUnsignedInt ( KDB *  kdb,
Key *  key,
unsigned int *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterUnsignedLong()

int elektraNotificationRegisterUnsignedLong ( KDB *  kdb,
Key *  key,
unsigned long *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure

◆ elektraNotificationRegisterUnsignedLongLong()

int elektraNotificationRegisterUnsignedLongLong ( KDB *  kdb,
Key *  key,
unsigned long long *  variable 
)

Subscribe for automatic updates to a given variable when the given key value is changed.

On kdbGet iff the key is present and its content is valid, the registered variable is updated.

Parameters
handleplugin handle
keykey to watch for changes
variablevariable
Return values
1on success
0on failure