Contents

• NAME
• SYNOPSIS
  • F95 INTERFACE
  • C INTERFACE
• PURPOSE

NAME

     use_threads - Sets the number of threads to use  for  subse-
     quent parallel regions

SYNOPSIS

     SUBROUTINE USE_THREADS(NTHREADS)

     INTEGER NTHREADS

     SUBROUTINE USE_THREADS_64(NTHREADS)

     INTEGER*8 NTHREADS

  F95 INTERFACE
     SUBROUTINE USE_THREADS(NTHREADS)

     INTEGER :: NTHREADS

     SUBROUTINE USE_THREADS_64(NTHREADS)

     INTEGER(8) :: NTHREADS

  C INTERFACE
     #include <sunperf.h>

     void use_threads(int nthreads);

     void use_threads_64(long nthreads);

PURPOSE

     USE_THREADS(NTHREADS)  sets  the  number   of   threads   to
     MAX(1,NTHREADS)  to  use  for subsequent parallel regions by
     calling library routine OMP_SET_NUM_THREADS which is part of
     the  OpenMP Fortran Application Program Interface.  From the
     OpenMP Fortran Application Program Interface  which  can  be
     found      at      the      official     OpenMP     website,
     http://www.openmp.org/,
     OMP_SET_NUM_THREADS(scalar_integer_expression),        where
     scalar_integer_expression = MAX(1,NTHREADS), is described as
     follows:   "The  effect  of this function depends on whether
     dynamic adjustment of the number of threads is enabled.   If
     dynamic   adjustment   is   disabled,   the   value  of  the
     scalar_integer_expression is used as the number  of  threads
     for  all  subsequent parallel regions prior to the next call
     to this function; otherwise, the value is used as  the  max-
     imum number of threads that will be used.  This function has
     effect only when called from serial portions of the program.
     If  it  is  called  from  a portion of the program where the
     OMP_IN_PARALLEL function returns  .TRUE.,  the  behavior  of
     this function is unspecified."