tis_key_create(3)tis_key_create(3)NAMEtis_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
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 argu‐
ment 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 initial‐
ization 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 num‐
ber of keys per process (PTHREAD_KEYS_MAX) has been exceeded. Insuffi‐
cient memory exists to create the key. Invalid argument.
ERRORS
None
SEE ALSO
Functions: tis_getspecific(3), tis_key_delete(3), tis_once(3), tis_set‐
specific(3)
Manuals: Guide to DECthreads and Programmer's Guide
tis_key_create(3)
