Fixed OpenMP version such that omp_set_nested is not deprecated

[hfp]

No description provided.

[mgates3]

What's the motivation here? Please provide a description of what problem this is fixing.

[hfp]

GNU OpenMP and other OpenMP runtimes are warning about omp_set_nested being deprecated. The code suggests omp_set_max_active_levels is only available since OpenMP 5.0, which is not true.

[mgates3]

What compiler versions are you using? What is the value of the _OPENMP macro? Details help to reproduce issues. The compiler and execution output from the below code may help.

omp_set_nested was deprecated in OpenMP 5.0, which is what the comment in the code refers to.

Sample code

#include <stdio.h>
#include <omp.h>

int main( int argc, char** argv )
{
    //--------------------
    #if __clang__
        printf( "clang %d.%d.%d\n",
                __clang_major__, __clang_major__, __clang_patchlevel__ );
    #elif __GNUC__
        printf( "gcc %d.%d.%d\n",
                __GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__ );
    #else
        printf( "unknown compiler\n" );
    #endif

    //--------------------
    #if _OPENMP
        printf( "OpenMP %d\n", _OPENMP );
    #else
        printf( "no OpenMP available\n" );
    #endif

    //--------------------
    // Test if omp_set_nested generates deprecated warning.
    printf( "try omp_set_nested\n" );
    omp_set_nested( 1 );

    printf( "try omp_set_nested with guard\n" );
    #if _OPENMP && _OPENMP < 201811
        omp_set_nested( 1 );
    #endif

    return 0;
}

Sample output (gcc)

sh methane openmp> module load gcc/14
sh methane openmp> $CXX --version; $CXX -fopenmp -Wall -o versions versions.cc; echo; ./versions
g++ (Spack GCC) 14.1.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

gcc 14.1.0
OpenMP 201511
try omp_set_nested
try omp_set_nested with guard

No deprecation warnings are generated.

Sample output (clang)

sh methane openmp> module load llvm/11
sh methane openmp> $CXX --version; $CXX -fopenmp -Wall -o versions versions.cc; echo; ./versions
clang version 11.1.0 (https://github.com/spack/spack d82c9e7f2a2f4a59c4e80e7219f57b82dcb87b5d)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /apps/spacks/2024-07-19/opt/spack/linux-rocky9-x86_64/gcc-11.4.1/llvm-11.1.0-qrng5w6wli4jtuxygcjdplglvjlmqkhq/bin

clang 11.11.0
OpenMP 201811
try omp_set_nested
OMP: Info #270: omp_set_nested routine deprecated, please use omp_set_max_active_levels instead.
try omp_set_nested with guard

The unguarded call generates a deprecation warning, but the guarded call does not.