thr_setspecific(3thread)

thr_setspecific -- set thread-specific data

Synopsis

   cc [options] -Kthread file
   
   #include <thread.h>
   

   int thr_setspecific(thread_key_t key, void *value);

Description

thr_setspecific associates a thread-specific value with key. Different threads can bind different values to the same key.

If the value bound to key must be updated during the lifetime of the thread, the caller must release the storage associated with the old value before a new value is bound, or the storage is lost.

Parameters

key: key to which value is to be bound
value: pointer to thread-specific data, or NULL

key parameter

key is a key obtained with a previous call to thr_keycreate(3thread).

The effect of calling thr_setspecific with a key value not obtained with thr_keycreate or after key has been deleted with thr_keydelete is undefined.

value parameter

value is typically a pointer to blocks of dynamically-allocated memory that have been reserved for use by the calling thread. If value is NULL, the calling thread will give up a non-NULL reference to key.

Return values

thr_setspecific returns zero for success and an error number for failure.

Errors

If any of the following conditions is detected, thr_setspecific returns the corresponding value:

EINVAL: The key value is invalid.
ENOMEM: There is not sufficient memory available to establish the binding.

References

Intro(3thread), thr_getspecific(3thread), thr_keycreate(3thread), thr_keydelete(3thread)