VMS Help CC, Language topics, Builtin Functions, Branch on Bit Clear-Clear Interlocked  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The _BBCCI function performs the following functions in interlocked
  fashion:

   o  Returns the complement of the bit specified by the two
      arguments

   o  Clears the bit specified by the two arguments

  Syntax:

       typedef enum {_bbcci_oldval_1, _bbcci_oldval_0} _BBCCI_STATUS;

       _BBCCI_STATUS _BBCCI(int __position, void *__address);