DESCRIPTION
 Thread attributes are used to specify parameters to  pthread_create. One attribute object can be used in multiple calls to  pthread_create, with or without modifications between calls.  The  pthread_attr_init function initializes  attr with all the default thread attributes. 
 The  pthread_attr_destroy function destroys  attr. 
 The  pthread_attr_set* functions set the attribute that corresponds to each function name. 
 The  pthread_attr_get* functions copy the value of the attribute that corresponds to each function name to the location pointed to by the second function parameter.  
RETURN VALUES
 If successful, these functions return 0. Otherwise, an error number is returned to indicate the error.  
ERRORS
 The  pthread_attr_init function will fail if: