udev

udev — libudev context

Functions

struct udev * udev_ref ()
struct udev * udev_unref ()
struct udev * udev_new ()
void udev_set_log_fn ()
int udev_get_log_priority ()
void udev_set_log_priority ()
void * udev_get_userdata ()
void udev_set_userdata ()

Types and Values

struct udev

Object Hierarchy


Description

The context contains the default values read from the udev config file, and is passed to all library operations.

Functions

udev_ref ()

struct udev *
udev_ref (struct udev *udev);

Take a reference of the udev library context.

Parameters

udev

udev library context

 

Returns

the passed udev library context


udev_unref ()

struct udev *
udev_unref (struct udev *udev);

Drop a reference of the udev library context. If the refcount reaches zero, the resources of the context will be released.

Parameters

udev

udev library context

 

Returns

the passed udev library context if it has still an active reference, or NULL otherwise.


udev_new ()

struct udev *
udev_new (void);

Create udev library context. This reads the udev configuration file, and fills in the default values.

The initial refcount is 1, and needs to be decremented to release the resources of the udev library context.

Returns

a new udev library context


udev_set_log_fn ()

void
udev_set_log_fn (struct udev *udev,
                 void (*log_fn) (struct udev *udev, int priority, const char *file, int line, const char *fn, const char *format, va_list args));

The built-in logging writes to stderr. It can be overridden by a custom function, to plug log messages into the users' logging functionality.

Parameters

udev

udev library context

 

log_fn

function to be called for logging messages

 

udev_get_log_priority ()

int
udev_get_log_priority (struct udev *udev);

The initial logging priority is read from the udev config file at startup.

Parameters

udev

udev library context

 

Returns

the current logging priority


udev_set_log_priority ()

void
udev_set_log_priority (struct udev *udev,
                       int priority);

Set the current logging priority. The value controls which messages are logged.

Parameters

udev

udev library context

 

priority

the new logging priority

 

udev_get_userdata ()

void *
udev_get_userdata (struct udev *udev);

Retrieve stored data pointer from library context. This might be useful to access from callbacks like a custom logging function.

Parameters

udev

udev library context

 

Returns

stored userdata


udev_set_userdata ()

void
udev_set_userdata (struct udev *udev,
                   void *userdata);

Store custom userdata in the library context.

Parameters

udev

udev library context

 

userdata

data pointer

 

Types and Values

struct udev

struct udev;

Opaque object representing the library context.