PTHREAD_GETSPECIFIC(3C)PTHREAD_GETSPECIFIC(3C)NAME
pthread_getspecific, pthread_setspecific - manage thread-specific data
SYNOPSIS
cc -mt [ flag... ] file... -lpthread [ library... ]
#include <pthread.h>
int pthread_setspecific(pthread_key_t key, const void *value);
void *pthread_getspecific(pthread_key_t key);
DESCRIPTION
The pthread_setspecific() function associates a thread-specific value
with a key obtained by way of a previous call to pthread_key_create().
Different threads may bind different values to the same key. These val‐
ues are typically pointers to blocks of dynamically allocated memory
that have been reserved for use by the calling thread.
The pthread_getspecific() function returns the value currently bound to
the specified key on behalf of the calling thread.
The effect of calling pthread_setspecific() or pthread_getspecific()
with a key value not obtained from pthread_key_create() or after key
has been deleted with pthread_key_delete() is undefined.
Both pthread_setspecific() and pthread_getspecific() may be called from
a thread-specific data destructor function. However, calling
pthread_setspecific() from a destructor may result in lost storage or
infinite loops.
RETURN VALUES
The pthread_getspecific() function returns the thread-specific data
value associated with the given key. If no thread-specific data value
is associated with key, then the value NULL is returned.
Upon successful completion, the pthread_setspecific() function returns
0. Otherwise, an error number is returned to indicate the error.
ERRORS
The pthread_setspecific() function will fail if:
ENOMEM
Insufficient memory exists to associate the value with the
key.
The pthread_setspecific() function may fail if:
EINVAL
The key value is invalid.
The pthread_getspecific() function does not return errors.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Standard │
├────────────────────┼─────────────────┤
│MT-Level │ MT-Safe │
└────────────────────┴─────────────────┘
SEE ALSOpthread_key_create(3C), attributes(5), standards(5)
Mar 23, 2005 PTHREAD_GETSPECIFIC(3C)
