/sys$common/syshlp/helplib.hlb CC, Run-time functions, decc$set_reentrancy  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Controls the type of reentrancy that reentrant Compaq C RTL
  routines will exhibit.

  Syntax:

       #include <reentrancy.h>

       int decc$set_reentrancy(int type);

  Use one of the following values for type:

   o  C$C_AST (AST)

      Uses the _BBSSI builtin to perform simple locking around
      critical sections of RTL code, and it may additionally disable
      asynchronous system traps (AST)s in locked regions of code.
      This type of locking should be used when AST code contains
      calls to Compaq C RTL I/O routines.

   o  C$C_MULTITHREAD (multithread)

      Designed to be used in conjunction with the DECthreads product.
      It performs DECthreads locking and never disables ASTs.
      DECthreads must be available on your system to use this form of
      reentrancy.

   o  C$C_TOLERANT (tolerant)

      Uses the _BBSSI builtin to perform simple locking around
      critical sections of RTL code, but ASTs are not disabled.  This
      type of locking should be used when ASTs are used and must be
      delivered immediately.  TOLERANT is the default reentrancy
      type.

   o  C$C_NONE (none)

      Gives optimal performance in the Compaq C RTL, but does
      absolutely no locking around critical sections of RTL code.  It
      should only be used in a single-threaded environment when there
      is no chance that the thread of execution will be interrupted
      by an AST that would call the Compaq C RTL.