Thread-Specific Storage

Thread-Specific Storage. More...

Functions
int	globus_thread_key_create (globus_thread_key_t *key, globus_thread_key_destructor_func_t destructor)
	Create a key for thread-specific storage. More...
int	globus_thread_key_delete (globus_thread_key_t key)
	Delete a thread-local storage key. More...
void *	globus_thread_getspecific (globus_thread_key_t key)
	Get a thread-specific data value. More...
int	globus_thread_setspecific (globus_thread_key_t key, void *value)
	Set a thread-specific data value. More...

Detailed Description

Thread-Specific Storage.

The globus_thread_key_t data type acts as a key to thread-specific storage. For each key created by globus_thread_key_create(), each thread may store and retrieve its own value.

Function Documentation

globus_thread_getspecific()

void* globus_thread_getspecific

(

globus_thread_key_t

key

)

Get a thread-specific data value.

The globus_thread_getspecific() function returns the value associated with the thread-specific data key passed as its first parameter. This function returns NULL if the value has not been set by the current thread. The return value is undefined if the key is not valid.

Parameters

key	Thread-specific data key to look up.

Returns

The value passed to a previous call to globus_thread_setspecific() in the current thread for this key.

globus_thread_key_create()

int globus_thread_key_create	(	globus_thread_key_t *	key,
		globus_thread_key_destructor_func_t	destructor
	)

Create a key for thread-specific storage.

The globus_thread_key_create() function creates a new key for thread-specific data. The new key will be available for all threads to store a distinct value. If the function pointer destructor is non-NULL, then that function will be invoked when a thread exits that has a non-NULL value associated with the key.

Parameters

key	Pointer to be set to the new key.
destructor	Pointer to a function to call when a thread exits to free the key's value.

Returns

On success, globus_thread_create_key() will create a new key to thread-local storage and return GLOBUS_SUCCESS. If an error occurs, then the value of key is undefined and globus_thread_create_key() returns an implementation-specific non-zero error value.

globus_thread_key_delete()

int globus_thread_key_delete

(

globus_thread_key_t

key

)

Delete a thread-local storage key.

The globus_thread_key_delete() function deletes the key used for a thread-local storage association. The destructor function for this key will no longer be called after this function returns. The behavior of subsequent calls to globus_thread_getspecific() or globus_thread_setspecific() with this key will be undefined.

Parameters

key	Key to destroy.

Returns

On success, globus_thread_key_delete() will delete a thread-local storage key and return GLOBUS_SUCCESS. If an error occurs, then the value of key is undefined and globus_thread_create_key() returns an implementation-specific non-zero error value.

globus_thread_setspecific()

int globus_thread_setspecific	(	globus_thread_key_t	key,
		void *	value
	)

Set a thread-specific data value.

The globus_thread_setspecific() function associates a thread-specific value with a data key. If the key had a previous value set in the current thread, it is replaced, but the destructor function is not called for the old value.

Parameters

key	Thread-specific data key to store.
value	A pointer to data to store as the thread-specific data for this thread.

Returns

On success, globus_thread_setspecific() stores value in the thread-specific data for the specified key and returns GLOBUS_SUCCESS. If an error occurs, globus_thread_setspecific() returns an implementation-specific non-zero error code and does not modify the key's value for this thread.