Allocates a new udev context object and returns a pointer to it. This object is opaque and must not be accessed by the caller via different means than functions provided by libudev. Initially, the reference count of the context is 1.

Gibt zurück:

On success, returns a pointer to the allocated udev context. On failure, NULL is returned.

Acquire further references to a udev context object.

Parameter:

udev - A udev context object.

Gibt zurück:

the argument that was passed, unmodified.

Drop a reference to a udev context object. Once the reference count hits 0, the context object is destroyed and freed.

Parameter:

udev - A udev context object.

Gibt zurück:

always returns NULL.

Creates the device object based on information found in /sys, annotated with properties from the udev-internal device database. A syspath is any subdirectory of /sys, with the restriction that a subdirectory of /sys/devices (or a symlink to one) represents a real device and as such must contain a uevent file.

Parameter:

udev - A udev context object.

syspath - The path of the device in /sys.

Gibt zurück:

a pointer to the allocated udev device. On failure, NULL is returned, and errno is set appropriately.

Create a udev enumerate object. Initially, the reference count of the enumerate object is 1.

Parameter:

udev - A udev context object.

Gibt zurück:

On success, returns a pointer to the allocated udev monitor. On failure, NULL is returned.

Acquire further references to a udev enumerate object.

Parameter:

udev_enumerate - A udev enumerate object.

Gibt zurück:

the argument that was passed, unmodified.

Drop a reference to a udev enumerate object. Once the reference count hits 0, the enumerate object is destroyed and freed.

Parameter:

udev_enumerate - A udev enumerate object.

Gibt zurück:

always returns NULL.

Modify filters of a udev enumerate object to match a subsystem.

Parameter:

udev_enumerate - The udev enumerate object to modify.

subsystem - The subsystem to match

Gibt zurück:

an integer greater than, or equal to, 0 on success.

Query a udev enumerate object. Scans /sys for all devices which match the given filters. No matches will return all currently available devices.

Parameter:

udev_enumerate - The udev enumerate object, with optional filters.

Gibt zurück:

an integer greater than, or equal to, 0 on success.

Get the first list entry from a udev enumerate object.

Parameter:

udev_enumerate - The udev enumerate object.

Gibt zurück:

On success, returns a pointer to the first entry in the list of found devices. If the list is empty, or on failure, NULL is returned.

Gets the next entry in the enumeration.

Parameter:

list_entry - the current list entry

Gibt zurück:

On success, returns a pointer to the next list entry. If no such entry can be found, or on failure, NULL is returned.

Get the name of the udev list entry

Parameter:

list_entry - A udev list entry

Gibt zurück:

a pointer to a constant string representing the requested value. The string is bound to the lifetime of the list entry itself. On failure, NULL is returned.

Acquire further references to a udev device object.

Parameter:

udev_device - A udev device object.

Gibt zurück:

the argument that was passed, unmodified.

Drop a reference to a udev device object. Once the reference count hits 0, the device object is destroyed and freed.

Parameter:

udev_device - A udev device object.

Gibt zurück:

always returns NULL.

Gets the parent of a udev device

Parameter:

udev_device - A udev device object.

Gibt zurück:

a pointer to the parent device. No additional reference to this device is acquired, but the child device owns a reference to such a parent device. On failure, NULL is returned.

Gets the parent of a udev device matching a subsystem and devtype

Parameter:

udev_device - A udev device object.

subsystem - The subsystem to match

devtype - The device type to match

Gibt zurück:

a pointer to the parent device. No additional reference to this device is acquired, but the child device owns a reference to such a parent device. On failure, NULL is returned.

Gets the syspath of a udev device

Parameter:

udev_device - A udev device object.

Gibt zurück:

a pointer to a constant string that describes the syspath. The lifetime of this string is bound to the device it was requested on. On failure, may return NULL.

Gets the sysname of a udev device

Parameter:

udev_device - A udev device object.

Gibt zurück:

a pointer to a constant string that describes the sysname. The lifetime of this string is bound to the device it was requested on. On failure, may return NULL.

Gets the devnode of a udev device

Parameter:

udev_device - A udev device object.

Gibt zurück:

a pointer to a constant string that describes the devnode. The lifetime of this string is bound to the device it was requested on. On failure, may return NULL.

Gets the devtype of a udev device

Parameter:

udev_device - A udev device object.

Gibt zurück:

a pointer to a constant string that describes the devtype. The lifetime of this string is bound to the device it was requested on. On failure, may return NULL.

Gets the subsystem of a udev device

Parameter:

udev_device - A udev device object.

Gibt zurück:

a pointer to a constant string that describes the subsystem. The lifetime of this string is bound to the device it was requested on. On failure, may return NULL.

Retrieves a device attributesfrom a udev device.

Parameter:

udev_device - A udev device object.

sysattr - The attribute to retrieve.

Gibt zurück:

a pointer to a constant string of the requested value. On error, NULL is returned. Attributes that may contain NUL bytes should not be retrieved with udev_device_get_sysattr_value(); instead, read them directly from the files within the device's syspath.

Retrieves a device property from a udev device.

Parameter:

udev_device - A udev device object.

key - The property to retrieve.

Gibt zurück:

a pointer to a constant string of the requested value. On error, NULL is returned.