| TSS(3C) | Standard C Library Functions | TSS(3C) |
tss, tss_create,
tss_delete, tss_get,
tss_set —
#include <threads.h>
typedef void (*tss_dtor_t)(void *);
int
tss_create(tss_t *key,
tss_dtor_t dtor);
void
tss_delete(tss_t key);
void *
tss_get(tss_t key);
int
tss_set(tss_t key,
void *val);
tss_create() function creates a new thread-specific
data key. The key space is opaque and global to all threads in the process.
Each thread has its own value-space which can be manipulated with the
tss_get() and tss_set()
functions. A given key persists until tss_delete() is
called.
When a key is created, the value NULL is
associated with all current threads. When a thread is created, the value
NULL is assigned as the value for the entire
key-space.
A key may optionally be created with a destructor function
dtor. The function dtor will run
when the thread exits (see thrd_exit(3C)) if the value for
the key is not NULL. The key space's destructors may
be run in any order. When the destructor is run due to a thread exiting, all
signals will be blocked.
The tss_delete() function deletes the key
identify by key from the global name-space. When a key
is deleted, no registered destructor is called, it is up to the calling
program to free any storage that was associated with
key across all threads. Because of this property, it
is legal to call tss_delete() from inside a
destructor. Any destructors that had been associated with
key will no longer be called when a thread
terminates.
tss_get() function may be used to obtain the value
associated with key for the calling thread. Note that if
the calling thread has never set a value, then it will receive the default
value, NULL. tss_get() may be
called from a tss destructor.
tss_set() function sets the value of the key
key for the calling thread to
value, which may be obtained by subsequent calls to
tss_get. To remove a value for a specific thread, one
may pass NULL in as value.
Changing the value of a key with tss_set() does not
cause any destructors to be invoked. This means that
tss_set() may be used in the context of a destructor,
but special care must be taken to avoid leaking storage or causing an infinite
loop.
tss_create() and
tss_set() functions return
thrd_success. Otherwise, they return
thrd_error to indicate that an error occurred.
Upon successful completion, the tss_get()
function returns the thread-specific value associated with the given
key. If no thread-specific value is associated with
the key or an invalid key was passed in, then NULL
is returned.
| August 20, 2019 | illumos |