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 OMP_NESTED is defined and set to true, or if OMP_NUM_THREADS or 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:

omp_set_max_active_levels – Limits the number of active parallel regions, OMP_NESTED – Nested parallel regions

Reference:

OpenMP specification v4.5, Section 4.9