Description

   This routine initializes the condition variable attributes object
   specified by the attr argument with a set of default attribute
   values.

   When an attributes object is used to create a condition
   variable, the values of the individual attributes determine the
   characteristics of the new condition variable. Attributes objects
   act as additional arguments to condition variable creation.
   Changing individual attributes in an attributes object does not
   affect any condition variables that were previously created using
   that attributes object.

   You can use the same condition variable attributes object in
   successive calls to pthread_condattr_init(), from any thread.
   If multiple threads can change attributes in a shared attributes
   object, your program must use a mutex to protect the integrity of
   that attributes object.

   Results are undefined if this routine is called and the attr
   argument specifies a condition variable attributes object that is
   already initialized.

   Currently, on OpenVMS systems, no attributes affecting condition
   variables are defined; you cannot change any attributes in the
   condition variable attributes object. On Tru64 UNIX systems, the
   PSHARED attribute is defined.

   The pthread_condattr_init() and pthread_condattr_destroy()
   routines are provided for future expandability of the pthread
   interface and to conform with the POSIX.1 standard. These
   routines serve no useful function, because there are no pthread_
   condattr_set*() type routines available at this time.