specificdata(9) - NetBSD Manual Pages

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SPECIFICDATA(9)        NetBSD Kernel Developer's Manual        SPECIFICDATA(9)

specificdata, specificdata_domain_create, specificdata_domain_delete, specificdata_key_create, specificdata_key_delete, specificdata_init, specificdata_fini, specificdata_getspecific, specificdata_getspecific_unlocked, specificdata_setspecific, specificdata_setspecific_nowait -- manipulate arbitrary data attached to objects
#include <sys/specificdata.h> specificdata_domain_t specificdata_domain_create(); void specificdata_domain_delete(specificdata_domain_t sd); int specificdata_key_create(specificdata_domain_t sd, specificdata_key_t *keyp, specificdata_dtor_t dtor); void specificdata_key_delete(specificdata_domain_t sd, specificdata_key_t key); int specificdata_init(specificdata_domain_t sd, specificdata_reference *ref); void specificdata_fini(specificdata_domain_t sd, specificdata_reference *ref); void * specificdata_getspecific(specificdata_domain_t sd, specificdata_reference *ref, specificdata_key_t key); void * specificdata_getspecific_unlocked(specificdata_domain_t sd, specificdata_reference *ref, specificdata_key_t key); void specificdata_setspecific(specificdata_domain_t sd, specificdata_reference *ref, specificdata_key_t key, void *data); int specificdata_setspecific_nowait(specificdata_domain_t sd, specificdata_reference *ref, specificdata_key_t key, void *data);
The specificdata facility provides a mechanism for storing arbitrary data, identified by an index key, within containers which exist within the objects associated with a particular domain.
specificdata_domain_create() Create and initialize a new domain. specificdata_domain_delete(sd) Deletes domain sd. specificdata_key_create(sd, keyp, dtor) Create a new key for sd. If the dtor argument is not NULL, it specifies a destructor which will be called when a datum associated with the specified key is deleted from a container within the sd. The unique identifier of the created key is returned in keyp. specificdata_key_delete(sd, key) Delete a key for sd, and delete any associated data from all con- tainers within the domain. specificdata_init(sd, ref) Initialize the container ref for use in sd. specificdata_fini(sd, ref) Destroy the container ref, and destroy all of the data stuffed into the container. specificdata_getspecific(sd, ref, key) Retrieve the datum from the container ref associated with key. specificdata_getspecific_unlocked(sd, ref, key) Retrieve the datum from the container ref associated with key in a lockless manner. Care must be taken to ensure that no other thread could cause ref to become invalid (i.e. point at the wrong con- tainer) by issuing a setspecific() call or by destroying the con- tainer. specificdata_setspecific(sd, ref, key, data) Store data in the container ref and associate it with key. If a datum has previously been stored, the new value replaces the origi- nal; the original value is not destroyed, i.e. its destructor is not invoked. Note that there is no provision for removing a datum without replacing it. specificdata_setspecific_nowait(sd, ref, key, data) (Unimplemented)
The specificdata functionality is implemented in sys/kern/subr_specificdata.c. The header file <sys/sys/specificdata.h> describes the public interface.
The specificdata subsystem first appeared in NetBSD 4.0.
The specificdata subsystem was written by Jason Thorpe <thorpej@NetBSD.org>. This manual page was written by Paul Goyette <pgoyette@NetBSD.org>. NetBSD 9.1 June 16, 2018 NetBSD 9.1
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