.. Copyright 1988-2022 Free Software Foundation, Inc. This is part of the GCC manual. For copying conditions, see the copyright.rst file. .. index:: Environment Variable .. _omp_max_active_levels: OMP_MAX_ACTIVE_LEVELS -- Set the maximum number of nested parallel regions ************************************************************************** Description: Specifies the initial value for the maximum number of nested parallel regions. The value of this variable shall be a positive integer. If undefined, then if :envvar:`OMP_NESTED` is defined and set to true, or if :envvar:`OMP_NUM_THREADS` or :envvar:`OMP_PROC_BIND` are defined and set to a list with more than one item, the maximum number of nested parallel regions will be initialized to the largest number supported, otherwise it will be set to one. See also: :ref:`omp_set_max_active_levels`, :ref:`OMP_NESTED` Reference: :openmp:`4.5`, Section 4.9