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

  The _BBSSI function performs the following functions in interlocked
  fashion:

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

   o  Sets the bit specified by the two arguments

  Syntax:

       typedef enum {_bbssi_oldval_0, _bbcci_oldval_1} _BBSSI_STATUS;

       _BBSSI_STATUS _BBSSI(int __position, void *__address);