dap4/d4lib/src/main/java/dap4/dap4lib/netcdf/Nc4DMRCompiler.java
int[]
    getGroups(int gid)
            throws DapException
    {
        int ret, n;
        IntByReference ip = new IntByReference();
        errcheck(ret = nc4.nc_inq_grps(gid, ip, null));
        n = ip.getValue();
        int[] grpids = null;
        if(n > 0) {
            grpids = new int[n];
            errcheck(ret = nc4.nc_inq_grps(gid, ip, grpids));
        } else
            grpids = new int[0];
        return grpids;
    }
int[]
    getGroups(int gid)
            throws DapException
    {
        int ret, n;
        IntByReference ip = new IntByReference();
        errcheck(ret = nc4.nc_inq_grps(gid, ip, null));
        n = ip.getValue();
        int[] grpids = null;
        if(n > 0) {
            grpids = new int[n];
            errcheck(ret = nc4.nc_inq_grps(gid, ip, grpids));
        } else
            grpids = new int[0];
        return grpids;
    }
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