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tis_key_create(3) [osf1 man page]

tis_key_create(3)					     Library Functions Manual						 tis_key_create(3)

NAME
tis_key_create - Generates a unique thread-specific data key. LIBRARY
Standard C Library (libc.so, libc.a) SYNOPSIS
#include <tis.h> int tis_key_create( pthread_key_t *key, void (*destructor)(void *)); STANDARDS
None PARAMETERS
Address of a variable that receives the key value. This value is used in calls to tis_getspecific(3) and tis_setspecific(3) to get and set the value associated with this key. Address of a routine that is called to destroy the context value when a thread terminates with a non- NULL value for the key. Note that this argument is used only when threads are present. DESCRIPTION
This routine generates a unique thread-specific data key. The key argument points to an opaque object used to locate data. This routine generates and returns a new key value. The key reserves a cell. Each call to this routine creates a new cell that is unique within an application invocation. Keys must be generated from initialization code that is guaranteed to be called only once within each process. (See the tis_once(3) description for more information.) Your program can associate an optional destructor function with each key. At thread exit, if a key has a non-NULL destructor function pointer, and the thread has a non-NULL value associated with that key, the function pointed to is called with the current associated value as its sole argument. The order in which data destructors are called at thread termination is undefined. When threads are present, keys and any corresponding data are thread specific; they enable the context to be maintained on a per-thread basis. For more information about the use of tis_key_create(3) in a threaded environment, refer to the pthread_key_create(3) description. DECthreads imposes a maximum number of thread-specific data keys, equal to the symbolic constant PTHREAD_KEYS_MAX. RETURN VALUES
If an error condition occurs, this routine returns an integer value indicating the type of error. Possible return values are as follows: Successful completion. The system lacked the necessary resources to create another thread-specific data key, or the limit on the total number of keys per process (PTHREAD_KEYS_MAX) has been exceeded. Insufficient memory exists to create the key. Invalid argument. ERRORS
None RELATED INFORMATION
Functions: tis_getspecific(3), tis_key_delete(3), tis_once(3), tis_setspecific(3) Manuals: Guide to DECthreads and Programmer's Guide delim off tis_key_create(3)

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PTHREAD_KEY_CREATE(3)					   BSD Library Functions Manual 				     PTHREAD_KEY_CREATE(3)

NAME
pthread_key_create -- thread-specific data key creation 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 that is visible 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. If a key value has a non-NULL destructor function pointer, and the thread has a non-NULL value associated with the key at the time of thread exit, then the key value is set to NULL and the destructor function is called with the previous key value as its argument. The order of destructor calls at thread exit is unspecified. 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 outstanding non-NULL values, there are still some non-NULL values with associated 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
pthread_key_create() 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
pthread_key_create() conforms to ISO/IEC 9945-1:1996 (``POSIX.1''). BSD
April 4, 1996 BSD
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