pthread_cond_init(3T)													     pthread_cond_init(3T)

NAME

       pthread_cond_init(), pthread_cond_destroy() - initialize or destroy a condition variable

SYNOPSIS

PARAMETERS

	      cond	Pointer to the condition variable to be initialized or destroyed.

	      attr	Pointer  to  the  attributes  object that defines the characteristics of the condition variable to be initialized.  If the
			pointer is NULL, default attributes are used.

DESCRIPTION

       The function initializes the condition variable cond with the attributes attr.  If attr is NULL, the default condition variable	attributes
       are  used  to  initialize  the  attributes  object.  See pthread_condattr_init(3T) for a list of the default condition variable attributes.
       After successful initialization, the condition variable may be used in condition variable operations.  A condition variable should be  ini-
       tialized  only  once  or the resulting behavior is undefined.  The function provides a way to ensure that a condition variable is only ini-
       tialized once.

       The macro can be used to initialize condition variables that are statically allocated.  These condition variables will be initialized  with
       default attributes.  The function does not need to be called for statically initialized condition variables.

       If the process-shared attribute in the condition variable attributes object referenced by attr is defined as the condition variable must be
       allocated such that the processes sharing the condition variable have access to it.  This may be done through the memory-mapping  functions
       (see mmap(2)) or the shared memory functions (see shmget(2)).

       destroys  the condition variable cond.  This function may set cond to an invalid value.	The destroyed condition variable can be reinitial-
       ized using the function If the condition variable is used after destruction in any condition variable call, the resulting behavior is unde-
       fined.

       A  condition  variable should be destroyed only when there are no threads currently blocked on it.  Destroying a condition variable that is
       currently in use results in undefined behavior.

RETURN VALUE

       Upon successful completion, and return zero.  Otherwise, an error number is returned to indicate the error (the variable is not set).

ERRORS

       If any of the following occur, the function returns the corresponding error number:

	      The system does not have the available resources (other than memory)
			     to initialize the condition variable.

	      The specified condition variable is an already initialized condition
			     variable.	However, getting for reinitializing the condition variable cannot be  expected	all  the  time	since  the
			     behavior of reinitializing the condition variable is undefined.

	      The	     cond parameter points to an illegal address.

	      The value specified by
			     cond or attr is invalid.

	      There is insufficient memory available in which to initialize
			     the condition variable.

       If any of the following occur, the function returns the corresponding error number:

	      An attempt to destroy
			     cond while it is in use by another thread.

	      cond	     is not a valid condition variable.

WARNINGS

       The space for condition variable must be allocated before calling Undefined behavior will result if the process-shared attribute of attr is
       and the space allocated for the condition variable is not accessible to cooperating threads.

AUTHOR

       and were derived from the IEEE POSIX P1003.1c standard.

SEE ALSO

       pthread_cond_signal(3T), pthread_cond_wait(3T).

STANDARDS CONFORMANCE

								  Pthread Library					     pthread_cond_init(3T)