Uncaught ReferenceError: cve_entrada is not defined at HTMLSpanElement.onclick

I am using Datatable’s ServerSide, in which I need to put a modal for the “update” option but it does not execute the function to obtain the data, the data through the serverside if I bring it but the update I do not retrieve.

function consultar(){
    $(document).ready(function() {
    $('#tableMatPrima').DataTable( {
        "processing": true,
        "serverSide": true,
        "ajax": "serverSideentradas.php",
        "lengthMenu": [[15, 30, 45], [15, 30, 45]],
        "order": [3, 'desc'],
        "searching": true,
        "bDestroy": true,
        "columnDefs":[
                        {
                            "targets": [1, 2, 3, 4],
                            "className": 'dt-body-center'
                        },
                        {
                            "targets": 4,
                            "render": function(data, type, row, meta){
                                const cve_entrada = data;
                                return '<span class= "btn btn-warning" onclick= "obtenerDatos(cve_entrada)" data-toggle="modal" data-target="#modalMatPrimaUpdate" data-whatever="@getbootstrap"><i class="fas fa-edit"></i> </span>'
                            }
                        }
                    ],

     "language": {
         "lengthMenu": "Mostrar _MENU_ registros por página.",
         "zeroRecords": "No se encontró registro.",
         "info": "  _START_ de _END_ (_TOTAL_ registros totales).",
         "infoEmpty": "0 de 0 de 0 registros",
         "infoFiltered": "(Encontrado de _MAX_ registros)",
         "search": "Buscar: ",
         "processing": "Procesando...",
                  "paginate": {
             "first": "Primero",
             "previous": "Anterior",
             "next": "Siguiente",
             "last": "Último"
         }

     }

    } );
} );
}

function obtenerDatos(cve_entrada) {
    $.getJSON("modelo_entradas.php?consultar="+cve_entrada, function(registros){

        $('#comb_idu').val(registros[0]['cve_entrada']);
        $('#comb_mat_primau').val(registros[0]['nombre']);
        $('#comb_cantidadu').val(registros[0]['cantidad_entrada']);
    });
}