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tis_key_create(3)
NAME
  tis_key_create - Generates a unique thread-specific data key

SYNOPSIS
  #include <tis.h>

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

LIBRARY
  Standard C Library (libc.so, libc.a)

STANDARDS
  None

PARAMETERS
  key 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.

  destructor
      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:

  0   Successful completion.

  [EAGAIN]
      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.

  [ENOMEM]
      Insufficient memory exists to create the key.

  [EINVAL]
      Invalid argument.

ERRORS
  None

SEE ALSO
  Functions: tis_getspecific(3), tis_key_delete(3), tis_once(3),
  tis_setspecific(3)

  Manuals: Guide to DECthreads and Programmer's Guide

Index for Section 3

Alphabetical listing for T

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