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PTHREAD_KEY_CREATE(3)  FreeBSD Library Functions Manual	 PTHREAD_KEY_CREATE(3)

NAME
     pthread_key_create	-- thread-specific data	key creation

LIBRARY
     POSIX Threads Library (libpthread,	-lpthread)

SYNOPSIS
     #include <pthread.h>

     int
     pthread_key_create(pthread_key_t *key, void (*destructor)(void *));

DESCRIPTION
     The pthread_key_create() function creates a thread-specific data key vis-
     ible to all threads in the	process.  Key values provided by
     pthread_key_create() are opaque objects used to locate thread-specific
     data.  Although the same key value	may be used by different threads, the
     values bound to the key by	pthread_setspecific() are maintained on	a per-
     thread basis and persist for the life of the calling thread.

     Upon key creation,	the value NULL is associated with the new key in all
     active threads.  Upon thread creation, the	value NULL is associated with
     all defined keys in the new thread.

     An	optional destructor function may be associated with each key value.
     At	thread exit, if	a key value has	a non-NULL destructor pointer, and the
     thread has	a non-NULL value associated with the key, the function pointed
     to	is called with the current associated value as its sole	argument.  The
     order of destructor calls is unspecified if more than one destructor
     exists for	a thread when it exits.

     If, after all the destructors have	been called for	all non-NULL values
     with associated destructors, there	are still some non-NULL	values with
     associated	destructors, then the process is repeated.  If,	after at least
     [PTHREAD_DESTRUCTOR_ITERATIONS] iterations	of destructor calls for	out-
     standing non-NULL values, there are still some non-NULL values with asso-
     ciated destructors, the implementation stops calling destructors.

RETURN VALUES
     If	successful, the	pthread_key_create() function will store the newly
     created key value at the location specified by key	and returns zero.
     Otherwise an error	number will be returned	to indicate the	error.

ERRORS
     The pthread_key_create() function will fail if:

     [EAGAIN]		The system lacked the necessary	resources to create
			another	thread-specific	data key, or the system-
			imposed	limit on the total number of keys per process
			[PTHREAD_KEYS_MAX] would be exceeded.

     [ENOMEM]		Insufficient memory exists to create the key.

SEE ALSO
     pthread_getspecific(3), pthread_key_delete(3), pthread_setspecific(3)

STANDARDS
     The pthread_key_create() function conforms	to ISO/IEC 9945-1:1996
     (``POSIX.1'').

FreeBSD	9.3			 April 4, 1996			   FreeBSD 9.3

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS

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